
==== Front
J Diabetes
J Diabetes
10.1111/(ISSN)1753-0407
JDB
Journal of Diabetes
1753-0393
1753-0407
Wiley Publishing Asia Pty Ltd Melbourne

38169157
10.1111/1753-0407.13523
JDB13523
Original Article
Original Article
Kidney function trajectories, associated factors, and outcomes in multiethnic Asian patients with type 2 diabetes
Feng et al.
Feng Liang https://orcid.org/0000-0002-0252-0136
1
Bee Yong Mong 2
Fu Xiuju 3
Kwek Jia Liang 4
Chan Choong Meng 4
Jafar Tazeen H. https://orcid.org/0000-0001-7454-8376
1 5 tazeen.jafar@duke-nus.edu.sg

1 Program in Health Services & Systems Research Duke‐NUS Medical School Singapore Singapore
2 Department of Endocrinology Singapore General Hospital Singapore Singapore
3 Institute of High Performance Computing A*STAR Singapore Singapore
4 Department of Renal Medicine Singapore General Hospital Singapore Singapore
5 Duke Global Health Institute Durham North Carolina USA
* Correspondence
Tazeen H. Jafar, Program in Health Services & Systems Research, Duke NUS Medical School, Singapore, 8 College Road, 169857, Singapore.
Email: tazeen.jafar@duke-nus.edu.sg

02 1 2024
9 2024
16 9 10.1111/jdb.v16.9 e1352302 11 2023
04 5 2023
05 12 2023
© 2024 The Author(s). Journal of Diabetes published by Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.
https://creativecommons.org/licenses/by/4.0/ This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

We examined the trajectory of estimated glomerular filtrate rate (eGFR), associated risk factors, and its relationship with end‐stage kidney disease (ESKD) among a multiethnic patient population with type 2 diabetes in Singapore.

Methods

A follow‐up study included 62 080 individuals with type 2 diabetes aged ≥18 years in a multi‐institutional SingHealth Diabetes Registry between 2013 and 2019. eGFR trajectories were analyzed using latent class linear mixed models. Factors associated with eGFR trajectories were evaluated using multinomial logistic regression. The association of eGFR trajectories with ESKD was assessed via competing risk models.

Results

Trajectory of kidney function, determined by eGFR, was nonlinear. The trajectory pattern was classified as stable initially then gradual decline (75%), progressive decline (21.9%), and rapid decline (3.1%). Younger age, female sex, Malay ethnicity, lower‐income housing type, current smoking, higher glycated hemoglobin, lower low‐density lipoprotein, higher triglyceride, uncontrolled blood pressure, albuminuria, cardiovascular disease, hypertension, and higher eGFR levels each were associated with progressive or rapid decline. Compared with the trajectory of stable initially then gradual eGFR decline, progressive decline increased the hazard of ESKD by 6.14‐fold (95% confidence interval [CI]: 4.96–7.61)) and rapid decline by 82.55 folds (95% CI: 55.90–121.89).

Conclusions

Three nonlinear trajectory classes of kidney function were identified among multiethnic individuals with type 2 diabetes in Singapore. About one in four individuals had a progressive or rapid decline in eGFR. Our results suggest that eGFR trajectories are correlated with multiple social and modifiable risk factors and inform the risk of ESKD.

Highlights

Three estimated glomerular filtration rate (eGFR) trajectories were identified among Asian individuals with type 2 diabetes: stable initially then gradual decline (75%), progressive decline (21.9%), and rapid decline (3.1%)

Multiple factors were associated with progressive or rapid eGFR decline (eg, women, low socioeconomic status, high hemoglobin A1c, and albuminuria)

Progressive and rapid eGFR decline were associated with a higher risk of end‐stage kidney disease (ESKD)

Our results highlight the gender and social disparities in renal function decline and also underscore the potential benefit of multifactorial intervention targeting the modifiable risk factors to postpone ESKD.

albuminuria
estimated glomerular filtration rate
latent class linear mixed models
risk factors
trajectories
type 2 diabetes
Industry Alignment Fund‐Pre‐Positioning Programme (IAF‐PP)H19/01/a0/023 Agency for Science, Techonology and Research (A*STAR)Singapore General Hospital 10.13039/501100001469 Singapore Cardiac Data BankNational Heart Center Singapore source-schema-version-number2.0
cover-dateSeptember 2024
details-of-publishers-convertorConverter:WILEY_ML3GV2_TO_JATSPMC version:6.4.8 mode:remove_FC converted:23.09.2024
Feng L , Bee YM , Fu X , Kwek JL , Chan CM , Jafar TH . Kidney function trajectories, associated factors, and outcomes in multiethnic Asian patients with type 2 diabetes. Journal of Diabetes. 2024;16 (9 ):e13523. doi:10.1111/1753-0407.13523
==== Body
pmc1 INTRODUCTION

The global prevalence of diabetes mellitus (DM) has increased greatly in the past few decades 1 and has been projected to increase by about 17% (237 million) between 2019 and 2045, 2 which will lead to a substantial growth of diabetic kidney disease (DKD) and associated end‐stage kidney disease (ESKD). Asians are known to be more susceptible to diabetes than Western populations, 3 and much of the increase in DM has been in Asia. 1 In many Asian countries such as Singapore, South Korea, and Japan, >40% of ESKD is attributable to DM. 4 However, the chronic trajectory of kidney function among patients with diabetes is not well established.

Considerable variations in the patterns or trajectories of estimated glomerular filtration rate (eGFR) have been reported among patients with diabetes. 5 , 6 , 7 , 8 , 9 , 10 , 11 The heterogeneity in kidney function trajectory in patients with diabetes highlights the need for risk stratification of those at risk of accelerated loss of renal function, early institution of preventive therapy, and close monitoring. However, very few studies have been conducted among Asians with diabetes on longitudinal kidney function trajectories. 9 , 11 , 12 Also, previous studies were restricted to patients with preserved baseline renal function 9 or included mostly males. 12

We used trajectory modeling to describe trajectories of kidney function in patients with type 2 diabetes based on data from SingHealth Diabetes Registry (SDR), 13 a multi‐institutional diabetes registry in Singapore, from 2013 to 2019. We aimed to (a) characterize the different trajectories of eGFR changes over time before the occurrence of ESKD, (b) identify risk factors associated with various patterns of eGFR decline, and (c) define the relationship of the trajectories to ESKD.

2 METHODS

2.1 Population

Our data on individuals with type 2 diabetes were selected from SDR. 13 The SDR was established in 2015 and has been populated with data retrospectively and prospectively to cover the period from 2013 to 2019. It is updated annually, with patient data from electronic medical records across the primary and hospital‐based care continuum within SingHealth‐the largest healthcare cluster in Singapore. SingHealth comprises four acute hospitals, five national specialty centers, three community hospitals, and eight primary care clinics (SingHealth Polyclinics), 14 which cumulatively provide health services to ~50% of the population of Singapore. Individuals with diabetes were identified through diagnosis codes (International Classification of Diseases, Ninth Revision [ICD‐9], ICD‐10, Systematized Nomenclature of Medicine [SNOMED], and SingHealth Polyclinic Working Diagnosis Code [SHWKC]), prescription records for diabetes medications, or laboratory tests (fasting plasma glucose, oral glucose tolerance test, hemoglobin A1c [HbA1c]). 13 The SDR includes data on patient demographics, prescribed and dispensed medications, comorbidities, anthropometrics, laboratory tests, and health services utilization.

Using data from SDR, we identified 94 145 individuals with type 2 diabetes aged ≥18 years in 2013 (baseline of the study) and 81 329 of them had eGFR measurements at baseline. The study was approved by the National University of Singapore Institutional Review Board and SingHealth Centralised Institutional Review Board. Informed consent was not sought because the study analyzed anonymized datasets from the SDR in a sandbox environment. No human or animal studies involved or no ethical statement for the study.

2.2 Measurement

2.2.1 Study outcomes

The primary study outcome was the chronic eGFR trajectories evaluated by quarterly average eGFR. GFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation based on levels of serum creatinine, age at the time of serum creatinine measurement, race, and gender. 15 The secondary outcome was ESKD. Data on ESKD between 2013 and 2019 were traced in the Singapore Renal Disease Registry.

2.2.2 Covariates

The study baseline was 2013. Covariates included baseline age (18 to 65 years and ≥ 65 years), gender, ethnicity (Chinese, Indian, Malay, and others), socioeconomic status (SES), body mass index (BMI), smoking, HbA1c (<7.0%, ≥7 and ≤9%, and >9.0%), blood pressure (BP) control status, low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein cholesterol (HDL‐C), triglyceride, albuminuria, eGFR, cardiovascular disease (CVD), hypertension, and use of lipid‐lowering medication. SES was evaluated by housing type (one‐ to two‐room House Development Board [HDB] flats, three‐ to five‐room HDB flats, and condo or landed houses). BMI was calculated as weight in kilograms divided by the square of height in meters. Smoking was defined as current smoking (yes/no). Uncontrolled BP was defined as systolic BP ≥ 140 mm Hg or diastolic BP ≥ 90 mm Hg. Albuminuria was defined as either urine albumin and creatinine ratio (UACR) ≥30 mg/g or positive results for microalbuminuria by Micral strip test (Roche Diagnostics, Singapore). CVD was defined as the presence of coronary heart disease, heart failure, or stroke, which were identified by ICD‐10, SNOMED, and SHWKC. Hypertension was defined as the use of any antihypertensive drugs.

2.2.3 Statistical analysis

Continuous variables were described using mean ± SD or median and interquartile range (IQR), as appropriate. We compared means (or medians) and proportions between eGFR trajectory groups using analysis of variance (Kruskal–Wallis test, if appropriate), or the χ 2 test.

2.2.4 eGFR trajectories

eGFR trajectories were analyzed by modeling quarterly average eGFR using latent class linear mixed models. 16 We considered for each individual the eGFR measurements until ESKD, death, or the end of 2019. The number of quarters since baseline was considered as time of this data point in modeling and was converted to months when creating figures. Polynomial terms for follow‐up time, including linear, quadratic, and cubic terms, were specified to model the nonlinear trajectories. The random intercept term was specified in the model to account for individual departures from the mean trajectory of each class. At model convergence, each individual was assigned posterior likelihoods of belonging to each eGFR trajectory. Individuals were assigned to the class to which they had the highest likelihood of belonging. eGFR trajectories were evaluated in models controlling for baseline age, gender, and albuminuria. Missing data on baseline albuminuria were replaced by the next available follow‐up observation for the same individual. Information on albuminuria was still missing on 13 965 individuals after single imputation. We fitted the models with one to five classes and selected the optimal number by considering Bayesian information criterion (BIC), Akaike information criterion (AIC), posterior probability of membership (an average posterior probability >0.85 for all latent classes), sample size of each class (no less than 1% participants in any single trajectory class), and interpretability of patterns. 17 , 18 BIC and AIC values to the models adjusted for age, gender, and baseline albuminuria decreased with the increasing number of hypothesized classes of respective models and no models had a class of <1% of individuals (Table S1). Thus, neither BIC nor AIC nor sample size of an individual class was informative for the model selection. Of all the five models, only models with two and three classes had a mean posterior probability of >85% for all classes of the same model. We finally selected the model with three classes instead of two classes because it is more clinically interpretable.

As a comparison, we also applied traditional linear mixed‐effects regression to quarterly average eGFR and obtained the slope, assuming a linear decline in eGFR. Sensitivity analysis was also done by constructing unadjusted trajectory models and adjusted trajectory models where all missing baseline albuminuria was singly imputed via predictive mean matching (PMM) method.

2.2.5 Factors associated with eGFR trajectories

Factors associated with eGFR trajectories were evaluated using multinomial logistic regression. The baseline covariates were chosen based on previous studies 11 , 19 including age, gender, ethnicity, housing type, smoking, Hb1Ac, LDL‐C, HDL‐C, triglyceride, albuminuria, eGFR, BP control, CVD, hypertension, and lipid‐lowering medication use. Two models were constructed. Model 1 included age, gender, ethnicity, and housing type, and model 2 was a fully adjusted model including all aforementioned covariates. Because the majority of BMI data at baseline were missing, sensitivity analysis was done by adding baseline BMI into model 2. Available baseline BMI (n = 23 540) or baseline BMI imputed using the next available follow‐up value of the same individual (n = 60 541) was controlled for, respectively.

2.2.6 Association of eGFR trajectories with ESKD

Death before occurrence of ESKD and ESKD were considered as competing risks. Competing risk analysis was thus performed using Fine and Gray models 20 to evaluate the risk of ESKD associated with eGFR trajectories. Covariates in the models were the same as those in the fully adjusted logistic regression model. Due to missing data on covariates (Table 1), we conducted sensitivity analysis by repeating multinomial logistic regression and competing risk analysis based on multiply‐imputed data. We used multivariate imputation by chained equations to create 10 imputed datasets with the predictive mean matching method. Variables used in each imputation model were all the covariates plus trajectory class and ESKD except for those with a minimum proportion of usable cases of <25%. All imputations were done through the R package “mice.” 21

TABLE 1 Baseline (year 2013) characteristics and incident events of individuals with type 2 diabetes by eGFR trajectory groups (n = 62 080).

Variables	Total (n = 62 080)	Class 1 (n = 46 572)	Class 2 (n = 13 586)	Class 3 (n = 1922)	p value	
Baseline characteristics	
Age at entry (years), mean (SD)	64.1 (11.4)	64.2 (11.6)	64.5 (10.3)	60.4 (11.0)	<.001	
18 to 65, n (%)	31 509 (50.8)	23 566 (50.6)	6711 (49.4)	1232 (64.0)	<.001	
≥65, n (%)	30 571 (49.2)	23 006 (49.4)	6875 (50.6)	690 (35.9)		
Female	31 644 (51.0)	22 999 (49.4)	7549 (55.6)	1096 (57.0)	<.001	
Housing type, n (%)	
1 to 2 rooms HDB	4663 (7.9)	3328 (7.5)	1135 (8.7)	200 (11.0)	<.001	
3 to 5 rooms HDB	48 254 (81.2)	36 086 (80.9)	10 675 (82.2)	1493 (82.4)		
Condo or landed house	6478 (10.9)	5179 (11.6)	1180 (9.1)	119 (6.6)		
Missing, n	2685	1979	596	110		
Ethnicity, n (%)					<.001	
Chinese	44 702 (72.0)	33 985 (73.0)	9536 (70.1)	1181 (61.5)		
Indian	6311 (10.2)	4924 (10.6)	1190 (8.8)	197 (10.3)		
Malay	8558 (13.8)	5823 (12.5)	2299 (16.9)	436 (22.7)		
Others	2509 (4.0)	1840 (4.0)	561 (4.1)	108 (5.6)		
Body mass index (kg/m2)						
Mean (SD)	26.4 (4.5)	26.3 (4.5)	26.7 (4.6)	26.5 (4.9)	<.001	
Missing, n	38 540	29 071	8301	1168		
HbA1c (%)	
Median (IQR)	7.1 (6.5, 7.8)	7.0 (6.5, 7.7)	7.2 (6.6, 8.0)	7.8 (6.8,9.8)	<.001	
<7.0%, n (%)	27 373 (44.8)	21 580 (47.1)	5292 (39.5)	501 (26.6)	<.001	
≥7 and ≤ 9%, n (%)	27 254 (44.6)	20 110 (43.9)	6377 (47.6)	767 (40.7)		
>9.0%, n (%)	6466 (10.6)	4123 (9.0)	1725 (12.9)	618 (32.8)		
Missing, n	987	759	192	116		
Systolic blood pressure (mm Hg)	
Mean (SD)	131.0 (12.9)	130.2 (12.6)	133.0 (13.1)	135.7 (15.5)	<.001	
Missing, n	3742	2728	724	290		
Diastolic blood pressure (mm Hg)	
Mean (SD)	70.0 (8.0)	69.9 (7.9)	70.3 (8.0)	72.2 (9.0)	<.001	
Missing, n	3742	2728	724	290		
Uncontrolled BP a , n (%)	12 654 (21.7)	8703 (19.9)	3395 (26.4)	556 (34.1)	<.001	
Missing, n	3742	2728	724	290		
HDL cholesterol (mg/dl)						
Mean (SD)	51.6 (13.7)	51.7 (13.8)	51.3 (13.6)	49.4 (13.4)	<.001	
Missing, n	2305	1687	490	128		
LDL cholesterol (mg/dl)	
Mean (SD)	91.7 (27.5)	91.8 (27.1)	90.4 (27.6)	97.8 (33.2)	<.001	
Missing, n	2647	1885	591	171		
Triglyceride (mg/dl)	
Median (IQR)	115.1 (88.6, 159.4)	115.1 (88.6, 159.4)	124.0 (88.6, 168.3)	132.4 (97.4, 186)	<.001	
Ln (triglyceride), mean (SD)	4.8 (0.45)	4.8 (0.44)	4.8 (0.45)	4.9 (0.49)	<.001	
Missing, n	2247	1637	483	127		
Albuminuria b , n (%)	34 173 (55.1)	24 349 (52.3)	8459 (62.3)	1365 (71.0)	<.001	
eGFR (ml/min/1.73 m2), mean (SD)	82.4 (22.5)	82.4 (23.2)	81.5 (20.3)	87.7 (18.6)	<.001	
CVD, n (%)	14 349 (23.1)	10 517 (22.6)	3319 (24.4)	513 (26.7)	<.001	
Hypertension c , n (%)	53 734 (86.6)	39 550 (84.9)	12 464 (91.7)	1720 (89.5)	<.001	
ACEI or ARB, n (%)	43 573 (70.2)	31 549 (67.4)	10 537 (77.6)	1487 (77.4)	<.001	
Oral antidiabetic drugs, n (%)	50 204 (80.9)	36 613 (78.6)	11 775 (86.7)	1816 (94.5)	<.001	
Insulin use, n (%)	5265 (8.5)	3535 (7.6)	1319 (9.7)	411 (21.4)	<.001	
Lipid‐lowering medication use, n (%)	52 317 (84.3)	39 065 (83.9)	11 657 (85.8)	1595 (83.0)	<.001	
Incident events	
ESKD, n (%)	885 (1.4)	270 (0.6)	316 (2.3)	299 (15.6)	<.001	
CVD d , n (%)	7199 (15.1)	4912 (13.6)	1856 (18.1)	431 (30.6)	<.001	
CVD mortality, n (%)	1926 (3.1)	1388 (3.0)	428 (3.2)	110 (5.7)	<.001	
All‐cause mortality, n (%)	5733 (9.2)	4403 (9.5)	1022 (7.5)	308 (16.0)	<.001	
Abbreviations: ACEI, angiotensin‐converting enzyme inhibitor; ARB, angiotensin‐receptor blocker; BP, blood pressure; CVD, cardiovascular disease; eGFR, estimated glomerular filtration rate; ESKD, end‐stage kidney disease; HbA1c: hemoglobin A1c; HDB, Housing Development Board; HDL, high‐density lipoprotein; IQR, interquartile range; LDL, low‐density lipoprotein.

a Systolic BP > 140 mm Hg or diastolic BP > 90 mm Hg.

b Urine albumin creatinine ratio >30 mg/g or abnormal dipstick test, missing values of baseline albuminuria (n = 17 004) were imputed using next observation carried backward.

c Defined as use of any antihypertensive medication.

d Patients with CVD at baseline were excluded, and the denominator for the total samples and classes 1 to 3 were 47 731, 36 055, 10 267, and 1409, respectively.

Trajectory analyses was performed using ‘LCMM’ packages in R 4.1.0. Multinomial logistic regression and competing risk analysis were done using SAS, version 9.4 (SAS Institute, Inc, Cary, NC). A p value of <.05 was considered to indicate statistical significance.

3 RESULTS

3.1 Study population

A total of 81 329 individuals with type 2 diabetes in the SDR had eGFR at baseline. Of them, we excluded those who had ESKD or died at baseline (n = 2727), had only one average eGFR measurement between 2013 and 2019 (n = 2557) or had no baseline albuminuria (n = 13 965); thus final sample size was 62 080 individuals for adjusted trajectory analysis (Figure 1) The mean (SD) age of the 62 080 individuals was 64 (11.4) years, about half (51.0%) were women, 72% were Chinese, and 55% had albuminuria (30 mg/g or higher) (Table 1). Table S2 compares the characteristics of the 62 080 individuals with those excluded from the adjusted trajectory analysis (n = 13 965).

FIGURE 1 Flow chart showing the selection and follow‐up of study participants. eGFR, estimated glomerular filtration rate; ESKD, end‐stage kidney disease.

Of the cohort of 62 080 individuals with diabetes, 885 (1.4%) had incident ESKD during a median follow‐up period of 72 months (IQR: 69–78). The incident rate of ESKD was 2.24 (95% CI: 2.10–2.40) per 1000 person‐years during follow‐up.

There was a median of 11 (IQR: 8–19) serum creatinine (or eGFR) measurements per individual, and 1 045 769 measurements in total. This number was reduced to 9 (IQR:7–12) eGFR per individual and altogether 633 208 measurements after merging serial eGFR within a quarter (3 months) into a mean value, which was used in the trajectory modeling.

3.2 Trajectory of eGFR

Figure 2 represents the trajectories with three classes for a hypothetical man who is 65 years old and has no albuminuria at baseline. Similar trajectories were observed for a woman aged 65 years with no albuminuria at baseline (Figure S1). We named trajectory classes from adjusted models as follows: class 1, stable initially then gradual decline; class 2, progressive decline; and class 3 rapid decline. The majority of the individuals were in class 1 (n = 46 572, 75.0%), followed by those in class 2 (n = 13 586, 21.9%) and in class 3 (n = 1922,3.1%). Parameter estimates are reported for the adjusted three‐class model in Tables S3 to S5. Also, a plot of estimated mean trajectory in combination with the observed individual trajectories of 100 randomly selected individuals from each class indicated that individual variability was generally explained by latent group trajectories (Figure S2). According to the results from traditional linear mixed model, the rates of eGFR decline with adjustment for age were −1.06 (−1.07, −1.05), −4.54 (−4.57, 4.52), and − 9.93 (−9.99, 9.86) mL/min/1.73 m2 per year for individuals in classes 1 to 3, respectively (Table 2).

FIGURE 2 GFR trajectories and 95% confidence intervals (CI) defined by trajectory modeling adjusted for age, gender, and albuminuria at baseline (n = 62 080). Single imputation was done using next observation carried backward method for missing values of baseline albuminuria. Gray band denotes 95% CIs. The trajectory plot was derived from a three‐class model for a hypothetical 65‐year‐old man with no albuminuria at baseline. Trajectory class 1 (stable initially then gradual decline). Trajectory class 2 (progressive decline). Trajectory class 3 (rapid decline). eGFR, estimated glomerular filtration rate.

TABLE 2 Age‐adjusted annual change in eGFR in different trajectories.

	% of sample	Mean (SD) baseline eGFR (mL/min/1.73 m2)	Slope (95% CI) (mL/min/1.73 m2/year)	p value	
Class 1	76.0	82.4 (23.2)	−1.06 (−1.07, −1.05)	<.001	
Class 2	20.6	81.5 (20.3)	−4.54 (−4.57, −4.52)	<.001	
Class 3	3.4	87.7 (18.6)	−9.93 (−9.99, −9.86)	<.001	
Abbreviations: eGFR, estimated glomerular filtration rate; 95% CI, 95% confidence interval.

3.3 Baseline characteristics and incident events by adjusted eGFR trajectories

The baseline characteristics by adjusted eGFR trajectories are shown in Table 1. A higher proportion of individuals with unfavorable cardiovascular profiles were found in the rapid decline (class 3) and progressive decline (class 2) groups compared with those in the group with initially stable eGFR followed by gradual decline (class 1). Similarly, higher proportions incident events were observed in class 2 and class 3 as compared with class 1.

3.4 Association of baseline clinical variables with kidney function trajectories

Table 3 summarized the association of baseline factors with eGFR trajectories from multinomial logistic regression with trajectory class 1 (stable initially then gradual decline) being the reference group. In model 1, female (vs male) sex, Malay ethnicity (vs Chinese), and lower‐cost housing type each were associated with increased odds of being in class 2 or 3. With adjustment for additional covariates in model 2, the associations remained significant. In model 2, female sex, Malay ethnicity, lower‐cost housing type, current smoking, higher Hb1Ac, higher triglyceride, albuminuria, higher eGFR levels, uncontrolled BP, CVD, and hypertension each were associated with a higher likelihood of being in both class 2 and class 3 as compared with class 1. For most factors, the association was stronger with class 3 than with class 2. Moreover, age ≥65 years was associated with a lower chance of belonging to class 3, with no impact on class 2. Indian ethnicity compared with Chinese ethnicity and higher LDL‐C levels were associated with a decreased chance of belonging to class 2, without affecting class 3. In contrast, no significant association was identified for HDL‐C and use of lipid‐lowering medication.

TABLE 3 Factors of being in class 2 or 3 versus class 1 by multinomial logistic regression.

Variables	Model 1 (n = 59 395)	Model 2 (n = 57 176)	
Class 2	Class 3	Class 2	Class 3	
Adjusted OR (95% CI)	p	Adjusted OR (95% CI)	p	Adjusted OR (95% CI)	p	Adjusted OR (95% CI)	p	
Age ≥ 65 years (vs 18 to 65 years)	1.05 (1.01, 1.09)	.025	0.60 (0.55, 0.67)	<.001	1.04 (0.99, 1.09)	.13	0.87 (0.76, 0.99)	.045	
Gender, women	1.26 (1.21,1.31)	<.001	1.38 (1.25,1.52)	<.001	1.31 (1.25, 1.37)	<.001	1.53 (1.35, 1.73)	<.001	
Ethnicity	
Chinese	1.00		1.00		1.00		1.00		
Indian	0.85 (0.80, 0.91)	<.001	1.05 (0.90, 1.23)	.52	0.85 (0.78, 0.91)	<.001	0.88 (0.73, 1.06)	.18	
Malay	1.36 (1.28,1.43)	<.001	1.83 (1.62, 2.06)	<.001	1.35 (1.27,1.44)	<.001	1.62 (1.40, 1.87)	<.001	
Others	1.08 (0.98, 1.19)	.13	1.61 (1.31, 1.98)	<.001	1.07 (0.96, 1.20)	.23	1.46 (1.14, 1.87)	.003	
Housing type	
Condo or landed house	1.00		1.00		1.00		1.00		
1 to 2 rooms HDB	1.41 (1.29,1.56)	<.001	2.20 (1.74,2.78)	<.001	1.26 (1.14,1.40)	<.001	1.40 (1.08,1.83)	.012	
3 to 5 rooms HDB	1.26 (1.17, 1.34)	<.001	1.56 (1.29, 1.88)	<.001	1.18 (1.10, 1.27)	<.001	1.22 (0.99, 1.50)	.062	
Current smoking (vs not)					1.08 (1.00,1.18)	.065	1.60 (1.33, 1.92)	<.001	
HbA1C	
<7.0%					1.00		1.00		
≥7 and ≤ 9%					1.28 (1.22, 1.34)	<.001	1.43 (1.25,1.63)	<.001	
>9.0%					1.81 (1.67, 1.95)	<.001	4.41 (3.76, 5.18)	<.001	
LDL cholesterol, per 10 mg/dL increase					0.97 (0.96, 0.98)	<.001	1.00 (0.98, 1.02)	.63	
HDL cholesterol, per 10 mg/dL increase					0.99 (0.97, 1.01)	.25	0.97 (0.92, 1.02)	.20	
Ln (triglyceride cholesterol)					1.18 (1.12, 1.25)	<.001	1.26 (1.09, 1.46)	.002	
Albuminuria a					1.37 (1.31, 1.43)	<.001	2.17 (1.92, 2.45)	<.001	
Baseline eGFR, per 10 mL/min/1.73 m2 increase					1.03 (1.02, 1.04)	<.001	1.15 (1.12,1.18)	<.001	
Uncontrolled BP b					1.33 (1.26, 1.40)	<.001	1.72 (1.52, 1.94)	<.001	
Cardiovascular disease					1.07 (1.02, 1.13)	.009	1.38 (1.21, 1.57)	<.001	
Hypertension c					1.77 (1.64, 1.92)	<.001	1.91 (1.56, 2.33)	<.001	
Lipid‐lowering medication					1.02 (0.96, 1.09)	.46	0.90 (0.78, 1.05)	.18	
Note: Trajectory classes were based on covariate‐adjusted trajectory analysis controlling for baseline age, gender, and albuminuria. Missing values of baseline albuminuria were imputed using next observation carried backward method. Class 1 was the reference group. All variables were baseline measurements in 2013. Because of missing data on covariates 51 716 out of 62 080 were retained for analysis in model 2.

Abbreviations: 95% CI, 95% confidence interval; BP, blood pressure; eGFR, estimated glomerular filtration rate; HbA1c: hemoglobin A1c; HDB, Housing and Development Board; HDL, high‐density lipoprotein; LDL, low‐density lipoprotein; OR, odds ratio.

a Urine albumin creatinine ratio >30 mg/g or abnormal dipstick test, missing values of baseline albuminuria (n = 17 004) were imputed using next observation carried backward method.

b Systolic BP > 140 mm Hg or diastolic BP > 90 mm Hg.

c Defined as use of any antihypertensive.

3.5 Association of trajectories with ESKD

Table 4 shows the association between eGFR trajectory and the risk of ESKD from competing risk analysis. Proportional hazard assumption was examined via plots of Schoenfeld residuals versus time, and no violation was found. Relative to class 1 in the unadjusted model, class 2 raised the hazard of ESKD by 4.07 times (95% CI: 3.46–4.79), whereas class 3 increased it by 29.15 times (95% CI: 24.72–34.38). The associations were even stronger after controlling for confounding factors (hazard ratio [HR]: 6.14, 95% CI: 4.96–7.61 for class 2; HR: 82.55, 95% CI: 55.90–121.89 for class 3). After baseline eGFR was excluded from the model, the resulting adjusted HRs became markedly smaller (class 2: HR: 3.22, 95% CI: 2.65–3.92; Class 3: HR: 15.92, 95% CI: 12.66–20.03).

TABLE 4 Association of eGFR trajectory group with ESKD from 2013 to 2019.

Class	No. of events	Events per 1000 person‐year	Unadjusted	Adjusted a	
HR (95% CI)	p value	HR (95% CI)	p value	
1	270	0.91	1.00		1.00		
2	316	3.6	4.07 (3.46, 4.79)	<.001	6.14 (4.96,7.61)	<.001	
3	299	26.5	29.15 (24.72, 34.38)	<.001	82.55 (55.90, 121.89)	<.001	
Note: 51 716 out of 62 080 were retained for adjusted analysis because of missing data on covariates.

Abbreviations: eGFR, estimated glomerular filtration rate; ESKD, end‐stage kidney disease; HR, hazard ratio; 95% CI, 95% confidence interval.

a Adjusted for baseline characteristics including age, gender, ethnicity, housing type, smoking, hemoglobin A1c, low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol, triglyceride, blood pressure control status, albuminuria, cardiovascular disease, hypertension (ie, any antihypertensive drugs use), lipid‐lowering medication use, and eGFR.

3.6 Sensitivity analysis

We further conducted unadjusted trajectory analysis and adjusted trajectory analysis with missing baseline albuminuria imputed by PMM method. A similar pattern of change and class size were identified from both unadjusted (Figure S3) and adjusted models (Figure S4), suggesting the robustness of our trajectory analysis results.

Also, additional adjustment of baseline BMI or analysis of multiply imputed data yielded comparable results on factors associated with eGFR trajectories (Tables S6 and S7). The association of eGFR trajectories with ESKD was not materially changed in the analysis of multiply imputed data (Table S8).

4 DISCUSSION

Our analysis of longitudinal eGFR trajectories on 62 080 patients with type 2 diabetes before the onset of ESKD identified three distinct nonlinear trajectory patterns showing that eGFR in the majority remained stable initially then declined gradually (class 1), or one in five patients showed a progressive decline (class 2), and a small minority had a rapid decline (class 3) in eGFR. We observed that female sex, Malay ethnicity, lower‐cost housing type, current smoking, higher Hb1Ac, higher triglyceride, albuminuria, higher eGFR levels, uncontrolled BP, CVD, and hypertension each were positively associated with both progressive and rapid decline in eGFR. Notably, age ≥ 65 years was exclusively related to a reduced chance of rapid eGFR decline, whereas Indian ethnicity and higher LDL‐C were solely associated with a decreased chance of progressive decline. Progressively and rapidly declining eGFR trajectories were both associated with ESKD. To our knowledge, this is the largest study of its kind examining eGFR trajectories in patients with type 2 diabetes. Understanding trajectories of kidney function before the onset of ESKD may help risk stratification of the patients for close monitoring. Sharing the trajectories can facilitate provider‐patient discussions on the prognosis, and shared decision making about therapies. Additionally, our results highlight the gender and social disparities in renal function decline and also underscore the potential benefit of multifactorial intervention targeting the modifiable risk factors to postpone ESKD.

Our findings of three distinct change patterns of trajectory classes (stable then gradual decline, progressive decline, and rapid decline) are consistent with an earlier, albeit much smaller, study of 6330 Chinese individuals with type 2 diabetes and preserved baseline renal function (eGFR>60 mL/min/1.73 m2). 9 By contrast, another study of 24 723 Chinese participants with prediabetes or diabetes showed that most (about 86%) of the participants had either stable or increasing eGFR trajectories. 12 A few explanations are possible for the observed differences. First, it has been shown that prediabetes does not predict eGFR decline in the general population. 22 Second, study participants were mostly men (84%) whose kidney function was reported to be less negatively affected by hyperglycemia than women. 23 Further data are required to elucidate the longitudinal eGFR trajectories among Asians with diabetes and prediabetes.

We observed that older age (age ≥ 65 years) was associated with a lower risk of rapid eGFR decline. This can be explained by the fact that older patients may pass away due to other diseases before experiencing a rapid eGFR decline. Our results concur with earlier studies showing a higher likelihood of progressive or rapid decline in kidney function among women vs men 24 , 25 and patients with low SES, 26 , 27 the latter defined as those living in low‐income housing type. The association of women with faster eGFR decline is somewhat controversial. However, estrogen loss could play an important role in explaining the gender disparity observed. Kidney function has been reported to decrease faster in postmenopausal women as compared with men of similar age. 28 Moreover, women with diabetes seem to lose the protective effects of estrogen on the cardiovascular bed, even before menopause. 24 Additionally, the unfavorable CVD risk profiles in women with type 2 diabetes might also contribute to their higher risk of kidney function decline. 29 We have previously shown that living in smaller public housing is associated with an increased risk of type 2 diabetes, and that residing in smaller public housing is likely to be a useful surrogate for lower SES in Singapore. 30 We now show that living in small public houses is also associated with a faster decline in kidney function. Our findings have implications that although the underlying social determinants of kidney disease in patients with type 2 diabetes need to be addressed, more health care resources for better access to health care could be provided in the areas with more public housing to eliminate the health disparities in the risk of ESKD.

In our study, high HbA1c (>9.0%) was the strongest correlate of progressive and rapid kidney function decline. Higher level of HbA1c has been consistently shown to be a risk factor for rapid kidney function decline among patients with diabetes. 9 , 11 , 19 , 31 The relationship has been suggested to be possibly mediated by hyperfiltration 31 and a higher risk of microvascular complications including retinopathy and neuropathy. 32 , 33 Lowering HbA1c slows DKD progression. 32 , 33 , 34 , 35

Higher levels of LDL‐C were associated with a reduced likelihood of progressive eGFR decline in the study. Conflicting results have been reported on their association. 9 , 36 , 37 The reasons for the seemingly counterintuitive relationship are unclear. Of note, low LDL has been associated with high mortality by others probably reflecting comorbid states including malnutrition and inflammation. 38 It is also possible that patients with lower LDL‐C levels were more likely to use statins and had more risk factors for progression. Although the association persisted with adjustment of relevant confounders, residual confounding or unmeasured confounders that could not be adjusted for may also contribute to our findings. On the other hand, our study identified no significant relationship between LDL‐C and a rapid eGFR decline as previously reported. 39 Notably, both positive 37 and negative associations 9 have been documented in other research, indicating the need for additional data to clarify the relationship between LDL‐C and various patterns of eGFR decline.

Albuminuria is a known predictor of faster eGFR decline 9 , 40 and CVD mortality. 41 Several therapies including renin‐angiotensin‐aldosterone system (RAAS) blockers and sodium‐glucose cotransporter‐2 inhibitors are effective in slowing DKD progression and recommended by the recent 2020 Kidney Disease Improving Global Outcomes guidelines for management of DKD. 42 The association between elevated baseline eGFR and subsequent steeper eGFR decline was reported in other studies. 8 , 37 It probably reflects some patients with hyperfiltration and others who are malnourished from a concurrent illness, both of whom are more likely to have progressive kidney function decline. 43 , 44 Concurrent illness maybe associated with decreased muscle mass which could overestimate true GFR.

We found that both hypertension and uncontrolled BP were associated with a progressive and rapid decline in kidney function. Several epidemiological studies demonstrate a bidirectional relationship of hypertension with kidney disease 45 , 46 , 47 and hypertension is an established risk factor for ESKD. 48 , 49 Uncontrolled hypertension accelerates the loss of nephrons and hence GFR. 50 Sodium and water expansion, upregulated RAAS, sympathetic overactivity, endothelial damage, and other cellular mechanisms are some mediators of CKD‐induced hypertension. 50 Several trials including the UK Prospective Diabetes Study show the benefit of lowering elevated BP in patients with diabetes in slowing progression to ESKD. 51 , 52 This study revealed that classes 2 and 3 individuals had greater RAAS blockers usage than class 1, indicating more severe disease and appropriate treatment for the two classes. This underscores the role of renoprotective agents in influencing eGFR trajectory differences. Current smoking and higher triglycerides are potentially modifiable risk factors for faster decline in kidney function in our study and are known predictors of CVD as well. 53

As noted in earlier studies, 54 , 55 we found that both progressive and rapid eGFR decline were associated with a higher risk of ESKD. The decline in kidney function may act as a biological biomarker of adverse vascular conditions 56 and might also cause decreased appetite and reduced physical function, thereby indirectly contributing to higher ESKD risk. 57 Furthermore, adjusting for covariates notably strengthened the correlation between eGFR trajectories and ESKD, indicating the presence of potential negative confounders. This negative confounding effect primarily stems from baseline eGFR. It is well established that GFR has a negative association with ESKD, 58 and our study revealed a positive association between baseline eGFR and subsequent eGFR decline. Moreover, removing baseline eGFR from the multivariable model lead to HRs for ESKD associated with eGFR trajectories smaller than unadjusted HRs, further supporting the role of baseline eGFR as a potential negative confounder. Our data highlight the necessity of earlier intervention based on GFR trajectories to delay the detrimental decline in kidney function and the progression to adverse clinical outcomes such as ESKD.

The main strengths of this study are the largest sample size of multiethnic Asian patients with type 2 diabetes examining eGFR trajectories, a large number of eGFR measurements for most patients over a 7‐year follow‐up, complete follow‐up data on ESKD from a comprehensive diabetes registry, and consistent results on sensitivity analysis. There are several limitations in this study. First, informed presence bias with more frequent analysis of the sicker population leading to potentially spurious associations is always a possibility in the analysis of electronic health record data. 59 However, the majority of patients with data in SDR visited polyclinics proactively on regularly scheduled appointments and thereby minimizing selection bias. Second, we fitted the model by using mean eGFR value of each follow‐up quarter rather than using all available measurements. Changes in eGFR within a very short period (ie, within a quarter) would be neglected and potentially introduce bias. However, our primary interest was in subacute or chronic changes in eGFR over a longer duration and not short‐term variations, which are more likely to be transient and results of hydration status, side effects of medication, or acute systemic illness. Third, residual confounding cannot be eliminated. Due to a significant proportion of missing data on UACR (92%), we define albuminuria based on UACR and dipstick tests, the latter without being a semiquantitative test, even though small changes in urine albumin can carry distinct risks for ESKD. 60 However, this approach has been used in previous studies. 61 , 62 Also, duration of diabetes was not accounted for in our analysis. Finally, some characteristics of the excluded individuals were different from the included. The excluded, compared with the included, had higher systolic BP, LDL‐C, triglyceride levels, lower eGFR, and a higher proportion of CVD, indicating a worse prognosis. But the analysis results based on data from multiple imputations were consistent. Thus, we believe our findings are robust.

In conclusion, our study revealed three distinct eGFR trajectories of patients with type 2 diabetes in Singapore: (a) stable initially then gradual decline (class 1), (b) progressive decline (class 2), and (c) rapid decline (class 3). Younger age, female sex, Malay (vs Chinese) ethnicity, lower‐cost housing type, current smoking, higher HbA1c, lower LDL‐C, higher triglyceride, albuminuria, higher eGFR levels, uncontrolled BP, CVD, and hypertension, each, were associated with a progressive or rapid decline in kidney function. Both progressive decline and rapid decline vs stable initially then gradual decline were associated with a greater risk of ESKD. More studies are needed to explore strategies to reduce the risk of ESKD among patients with diabetes in class 2 and 3.

CONFLICT OF INTEREST STATEMENT

All the authors declared no competing interests.

Supporting information

Data S1. Supporting Information.

ACKNOWLEDGEMENTS

This study was funded by Industry Alignment Fund‐Pre‐Positioning Programme (IAF‐PP) (grant number: H19/01/a0/023) from Agency for Science, Techonology and Research (A*STAR) in Singapore. We would like to thank the Health Service Research Unit (Singapore General Hospital) and the Singapore Cardiac Data Bank (National Heart Center Singapore) for their support. We would also like to express appreciation to the team from the National Registry of Diseases Office for providing ESKD data for this study.
==== Refs
REFERENCES

1 Zhou B , Lu Y , Hajifathalian K , et al. Worldwide trends in diabetes since 1980: a pooled analysis of 751 population‐based studies with 4· 4 million participants. Lancet. 2016;387 :1513‐1530.27061677
2 Saeedi P , Petersohn I , Salpea P , et al. Global and regional diabetes prevalence estimates for 2019 and projections for 2030 and 2045: results from the international diabetes federation diabetes atlas, 9(th) edition. Diabetes Res Clin Pract. 2019;157 :107843.31518657
3 Wulan SN , Westerterp KR , Plasqui G . Ethnic differences in body composition and the associated metabolic profile: a comparative study between Asians and Caucasians. Maturitas. 2010;65 :315‐319.20079586
4 United States Renal Data System . USRDS annual data report: epidemiology of kidney disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2021. 2021 Available from https://adr.usrds.org/2021/end-stage-renal-disease/11-international-comparisons. Accessed 13 Jan 2023.
5 Davis TM , Chubb SA , Davis WA . The relationship between estimated glomerular filtration rate trajectory and all‐cause mortality in type 2 diabetes: the Fremantle diabetes study. Eur J Endocrinol. 2016;175 :273‐285.27418062
6 Skupien J , Warram JH , Smiles AM , Stanton RC , Krolewski AS . Patterns of estimated glomerular filtration rate decline leading to end‐stage renal disease in type 1 diabetes. Diabetes Care. 2016;39 :2262‐2269.27647852
7 Peters KE , Davis WA , Ito J , et al. Identification of novel circulating biomarkers predicting rapid decline in renal function in type 2 diabetes: the Fremantle diabetes study phase II. Diabetes Care. 2017;40 :1548‐1555.28851702
8 Weldegiorgis M , de Zeeuw D , Li L , et al. Longitudinal estimated GFR trajectories in patients with and without type 2 diabetes and nephropathy. Am J Kidney Dis. 2018;71 :91‐101.29153995
9 Jiang G , Luk AOY , Tam CHT , et al. Progression of diabetic kidney disease and trajectory of kidney function decline in Chinese patients with type 2 diabetes. Kidney Int. 2019;95 :178‐187.30415941
10 Vistisen D , Andersen GS , Hulman A , Persson F , Rossing P , Jørgensen ME . Progressive decline in estimated glomerular filtration rate in patients with diabetes after moderate loss in kidney function‐even without albuminuria. Diabetes Care. 2019;42 :1886‐1894.31221677
11 Oshima M , Shimizu M , Yamanouchi M , et al. Trajectories of kidney function in diabetes: a clinicopathological update. Nat Rev Nephrol. 2021;17 :740‐750.34363037
12 Zuo Y , Wang A , Chen S , Tian X , Wu S , He Y . Distinct eGFR trajectories are associated with risk of myocardial infarction in people with diabetes or prediabetes. J Diabetes. 2021;13 :124‐133.32671918
13 Lim DYZ , Chia SY , Abdul Kadir H , Mohamed Salim NN , Bee YM . Establishment of the SingHealth diabetes registry. Clin Epidemiol. 2021;13 :215‐223.33762850
14 SingHealth key figures and statistics ; 2021. Available from: https://www.singhealth.com.sg/about‐singhealth/newsroom/Documents/SingHealth%20Duke‐NUS%20AR1920‐OVERVIEW_final.pdf. Accessed 20 Jan 2023.
15 Levey AS , Stevens LA , Schmid CH , et al. A new equation to estimate glomerular filtration rate. Ann Intern Med. 2009;150 :604‐612.19414839
16 Proust‐Lima C , Philipps V , Liquet B . Estimation of extended mixed models using latent classes and latent processes: the R package lcmm. Journal of Statistical Software. 2017;78 :1‐56.
17 Van De Schoot R , Sijbrandij M , Winter SD , et al. The GRoLTS‐checklist: guidelines for reporting on latent trajectory studies. Strucct Equ Modelling. 2017;24 :451‐467.
18 Nguena Nguefack HL , Pagé MG , Katz J , et al. Trajectory modelling techniques useful to epidemiological research: a comparative narrative review of approaches. Clin Epidemiol. 2020;12 :1205‐1222.33154677
19 Macisaac RJ , Ekinci EI , Jerums G . Markers of and risk factors for the development and progression of diabetic kidney disease. Am J Kidney Dis. 2014;63 :S39‐S62.24461729
20 Fine JP , Gray RJ . A proportional hazards model for the subdistribution of a competing risk. J Am Stat Assoc. 1999;94 :496‐509.
21 Van Buuren S , Groothuis‐Oudshoorn K . Mice: multivariate imputation by chained equations in R. J Stat Softw. 2011;45 :1‐67.
22 Furukawa M , Onoue T , Kato K , et al. Prediabetes is associated with proteinuria development but not with glomerular filtration rate decline: a longitudinal observational study. Diabet Med. 2021;38 :e14607.34031914
23 Cherney DZI , Sochett EB , Miller JA . Gender differences in renal responses to hyperglycemia and angiotensin‐converting enzyme inhibition in diabetes. Kidney Int. 2005;68 :1722‐1728.16164648
24 Giandalia A , Giuffrida AE , Gembillo G , et al. Gender differences in diabetic kidney disease: focus on hormonal, genetic and clinical factors. Int J Mol Sci. 2021;22 :5808.34071671
25 Kajiwara A , Kita A , Saruwatari J , et al. Sex differences in the renal function decline of patients with type 2 diabetes. J Diabetes Res. 2016;2016 :4626382.27247948
26 Ravid M , Brosh D , Ravid‐Safran D , Levy Z , Rachmani R . Main risk factors for nephropathy in type 2 diabetes mellitus are plasma cholesterol levels, mean blood pressure, and hyperglycemia. Arch Intern Med. 1998;158 :998‐1004.9588433
27 Dunkler D , Kohl M , Heinze G , et al. Modifiable lifestyle and social factors affect chronic kidney disease in high‐risk individuals with type 2 diabetes mellitus. Kidney Int. 2015;87 :784‐791.25493953
28 Jafar TH , Schmid CH , Stark PC , et al. The rate of progression of renal disease may not be slower in women compared with men: a patient‐level meta‐analysis. Nephrol Dial Transplant. 2003;18 :2047‐2053.13679479
29 Penno G , Solini A , Bonora E , et al. Gender differences in cardiovascular disease risk factors, treatments and complications in patients with type 2 diabetes: the RIACE Italian multicentre study. J Intern Med. 2013;274 :176‐191.23565931
30 Vanitha D , Porhcisaliyan O , Wang Y , et al. Socioeconomic status and ethnic variation associated with type 2 diabetes mellitus in patients with uncontrolled hypertension in Singapore. BMJ Open Diabetes Res Care. 2021;9 :e002064.
31 Low S , Zhang X , Wang J , et al. Long‐term prospective observation suggests that glomerular hyperfiltration is associated with rapid decline in renal filtration function: a multiethnic study. Diab Vasc Dis Res. 2018;15 :417‐423.29807475
32 Group UKPDS . Intensive blood‐glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet. 1998;352 :837‐853.9742976
33 Nathan DM , Genuth S , Lachin J , et al. The effect of intensive treatment of diabetes on the development and progression of long‐term complications in insulin‐dependent diabetes mellitus. N Engl J Med. 1993;329 :977‐986.8366922
34 Patel A , MacMahon S , Chalmers J , et al. Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes. N Engl J Med. 2008;358 :2560‐2572.18539916
35 Ismail‐Beigi F , Craven T , Banerji MA , et al. Effect of intensive treatment of hyperglycaemia on microvascular outcomes in type 2 diabetes: an analysis of the ACCORD randomised trial. Lancet. 2010;376 :419‐430.20594588
36 Seliger SL . Inflammation and dyslipidemia in nephropathy: an epidemiologic perspective. Kidney Int. 2006;69 :206‐208.16408107
37 Low S , Tai ES , Yeoh LY , et al. Onset and progression of kidney disease in type 2 diabetes among multi‐ethnic Asian population. J Diabetes Complications. 2016;30 :1248‐1254.27291338
38 Bowden RG , La Bounty P , Shelmadine B , et al. Reverse epidemiology of lipid‐death associations in a cohort of end‐stage renal disease patients. Nephron Clin Pract. 2011;119 :c214‐c219.21832847
39 Zoppini G , Targher G , Chonchol M , et al. Predictors of estimated GFR decline in patients with type 2 diabetes and preserved kidney function. Clin J Am Soc Nephrol. 2012;7 :401‐408.22282481
40 Turin TC , James M , Ravani P , et al. Proteinuria and rate of change in kidney function in a community‐based population. J Am Soc Nephrol. 2013;24 :1661‐1667.23833255
41 Fox CS , Matsushita K , Woodward M , et al. Associations of kidney disease measures with mortality and end‐stage renal disease in individuals with and without diabetes: a meta‐analysis. Lancet. 2012;380 :1662‐1673.23013602
42 de Boer IH , Caramori ML , Chan JCN , et al. Executive summary of the 2020 KDIGO diabetes management in CKD guideline: evidence‐based advances in monitoring and treatment. Kidney Int. 2020;98 :839‐848.32653403
43 Tonneijck L , Muskiet MH , Smits MM , et al. Glomerular Hyperfiltration in diabetes: mechanisms, clinical significance, and treatment. J Am Soc Nephrol. 2017;28 :1023‐1039.28143897
44 Su WY , Chu NS , Huang JC , et al. Low albumin, Low bilirubin, and high Alfa‐fetoprotein are associated with a rapid renal function decline in a large population follow‐up study. J Pers Med. 2021;11 :781.34442425
45 Bidani AK , Griffin KA . Pathophysiology of hypertensive renal damage: implications for therapy. Hypertension. 2004;44 :595‐601.15452024
46 Kestenbaum B , Rudser KD , De Boer IH , et al. Differences in kidney function and incident hypertension: the multi‐ethnic study of atherosclerosis. Ann Intern Med. 2008;148 :501‐508.18378946
47 Zhang M , Jiang Y , Zhang Q , et al. Bidirectional and temporal association between hypertension and microalbuminuria: a longitudinal study in Chinese adults. J Am Heart Assoc. 2018;7 :e010723.30571489
48 Reynolds K , Gu D , Muntner P , et al. A population‐based, prospective study of blood pressure and risk for end‐stage renal disease in China. J Am Soc Nephrol. 2007;18 :1928‐1935.17475822
49 Bae EH , Lim SY , Kim B , et al. Effects of blood pressure according to age on end‐stage renal disease development in patients with diabetes: a Nationwide population‐based cohort study. Hypertension. 2022;79 :1765‐1776.35607989
50 Ku E , Lee BJ , Wei J , Weir MR . Hypertension in CKD: Core curriculum 2019. Am J Kidney Dis. 2019;74 :120‐131.30898362
51 UK Prospective Diabetes Study Group . Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38. UK Prospective Diabetes Study Group. BMJ. 1998;317 :703‐713.9732337
52 Bakris GL , Toto RD , McCullough PA , et al. Effects of different ACE inhibitor combinations on albuminuria: results of the GUARD study. Kidney Int. 2008;73 :1303‐1309.18354383
53 Barrett‐Connor EWD , Wong N , Goldberg R . Heart disease and diabetes. In: Cowie CC , Casagrande SS , Menke A , et al., eds. Diabetes in America. 3rd ed. National Institute of Diabetes and Digestive and Kidney Diseases (US); 2018 Aug ch. 18. Available from: https://www-ncbi-nlm-nih-gov.libproxy1.nus.edu.sg/books/NBK568001/.
54 Oshima M , Toyama T , Haneda M , et al. Estimated glomerular filtration rate decline and risk of end‐stage renal disease in type 2 diabetes. PLoS One. 2018;13 :e0201535.30071057
55 Shimizu M , Furuichi K , Toyama T , et al. Decline in estimated glomerular filtration rate is associated with risk of end‐stage renal disease in type 2 diabetes with macroalbuminuria: an observational study from JDNCS. Clin Exp Nephrol. 2018;22 :377‐387.28889347
56 Turin TC , Coresh J , Tonelli M , et al. One‐year change in kidney function is associated with an increased mortality risk. Am J Nephrol. 2012;36 :41‐49.22699706
57 Rifkin DE , Shlipak MG , Katz R , et al. Rapid kidney function decline and mortality risk in older adults. Arch Intern Med. 2008;168 :2212‐2218.19001197
58 Levey AS , de Jong PE , Coresh J , et al. The definition, classification, and prognosis of chronic kidney disease: a KDIGO controversies conference report. Kidney Int. 2011;80 :17‐28.21150873
59 Goldstein BA , Bhavsar NA , Phelan M , Pencina MJ . Controlling for informed presence bias due to the number of health encounters in an electronic health record. Am J Epidemiol. 2016;184 :847‐855.27852603
60 Gansevoort RT , Matsushita K , van der Velde M , et al. Lower estimated GFR and higher albuminuria are associated with adverse kidney outcomes. A collaborative meta‐analysis of general and high‐risk population cohorts. Kidney Int. 2011;80 :93‐104.21289597
61 Tangri N , Grams ME , Levey AS , et al. Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta‐analysis. JAMA. 2016;315 :164‐174.26757465
62 Nagasu H , Yano Y , Kanegae H , et al. Kidney outcomes associated with SGLT2 inhibitors versus other glucose‐lowering drugs in real‐world clinical practice: the Japan chronic kidney disease database. Diabetes Care. 2021;44 :2542‐2551.34593566
