
==== Front
Medicine (Baltimore)
Medicine (Baltimore)
MD
Medicine
0025-7974
1536-5964
Lippincott Williams & Wilkins Hagerstown, MD

39029037
MD-D-24-04869
00039
10.1097/MD.0000000000038832
3
6900
Research Article
Observational Study
Relationship of psoriatic arthritis with nail and scalp involvement in Turkish psoriasis patients: Multicentered cross-sectional study
https://orcid.org/0000-0003-1413-9436
Askin Ozge MD a*
Engin Burhan MD burhanengin2000@yahoo.com
a
Ozdede Ayse MD ayseozdede@gmail.com
b
Kartal Selda Pelin MD pelin@dr.com
c
Ugurlu Serdal MD serdalugurlu@gmail.com
b
Akbulut Tugba Ozkok MD tugbaozkokablulut@gmail.com
d
Ekinci Algun Polat MD algunekinci@yahoo.com
e
Aydogdu İbrahim Halil MD aydogduibrahimhalil@gmail.com
e
Ozden Muge Guler MD mgulerozden@hotmail.com
f
Kok Huseyin MD khuseyinyfl@gmail.com
f
Dogan Sibel MD sibel.dogan@hacettepe.edu.tr
g
Ozturkcan Serap MD seralbercan@yahoo.com
h
Borlu Murat MD muratborlu@erciyes.edu.tr
i
Baskan Emel Bulbul MD bbemel@hotmail.com
j
Yilmaz Nazan MD dr.nazanyilmaz@hotmail.com
k
Ak Tumay MD tumayyakk@gmail.com
l
Topkarci Zeynep MD ztopkarci@yahoo.com
m
Serdaroglu Server MD serverserdaroglu@yahoo.com
a
a Deparment of Dermatology, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
b Department of Internal Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Division of Rheumatology, Istanbul, Turkey
c Department of Dermatology, University of Health Sciences, Etlik City Research and Education Hospital, Ankara, Turkey
d Department of Dermatology, Haseki Training and Research Hospital, Istanbul, Turkey
e Department of Dermatology, Istanbul University, Faculty of Medicine, Istanbul, Turkey
f Department of Dermatology, Ondokuzmayis University, Faculty of Medicine, Samsun, Turkey
g Department of Dermatology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
h Department of Dermatology, Celal Bayar University, Faculty of Medicine, Manisa, Turkey
i Department of Dermatology, Erciyes University, Faculty of Medicine, Kayseri, Turkey
j Department of Dermatology, Uludag University, Faculty of Medicine, Bursa, Turkey
k Department of Dermatology, Liv Hospital Ulus, Istanbul, Turkey
l Department of Internal Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
m Department of Dermatology, Bakirköy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey.
* Correspondence: Ozge Askin, Deparment of Dermatology, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul 34098, Turkey (e-mail: ozgee_karakus@hotmail.com).
19 7 2024
19 7 2024
103 29 e3883206 5 2024
13 6 2024
14 6 2024
Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial License 4.0 (CCBY-NC), where it is permissible to download, share, remix, transform, and buildup the work provided it is properly cited. The work cannot be used commercially without permission from the journal.

Psoriasis is a common multisystem inflammatory disease, and arthritis is an essential component of the disorder, requiring early diagnosis and prompt treatment for successful management. In this study, we aimed to investigate the relationship between nail and scalp involvement and other covariates with psoriatic arthritis (PsA). This cross-sectional study, conducted from June 2021 through December 2021, included 763 patients from 11 different centers in Turkey. The severity of involvement was evaluated using psoriasis area severity index (PASI), nail psoriasis severity index (NAPSI), and psoriasis scalp severity index (PSSI) scores. Predictors for PsA were evaluated using univariate and multivariate logistic regression models. PsA (n = 155, 21.5%) was significantly more common in patients having a family history of psoriasis (43.2% vs 30.9%, P = .004), nail involvement (68.4% vs 52.3%, P < .001), and coexistence of nail and scalp involvement (53.7% vs 39.6%, P = .002). Furthermore, patients with PsA had considerably higher PASI (7 vs 5.6, P = .006), NAPSI (5 vs 2, P < .001), and PSSI scores (7 vs 4, P = .002) and longer disease duration (months) (126 vs 108, P = .009). In multivariate analysis, female gender [OR: 3.01, 95% CI (1.861–4.880), P < .001], nail involvement [OR: 2.06, 95% CI (1.293–3.302), P = .002)], and body mass index (BMI) [OR: 1.06, 95% CI (1.017–1.100), P = .005] were identified as independent predictors for PsA. Female gender, nail involvement, and high BMI are significant predictors for PsA and warrant detailed rheumatological assessment. Notably, being female is the strongest predictor of increased risk of PsA in our survey. Scalp involvement appears not to be associated with PsA. Also, the presence of PsA seems related to a more severe skin involvement phenotype.

arthritis
interdisciplinary communication
nail diseases
psoriasis
psoriatic
scalp
OPEN-ACCESSTRUE
==== Body
pmc1. Introduction

Psoriasis is a chronic inflammatory disease primarily affecting the skin and the joints. Psoriasis may present with different clinical involvements that can progress from an erythematous squamous small plaque in the skin to erythroderma. It can also involve special areas, such as the scalp and the nails. Studies have shown that nail involvement is observed in 47.4% to 78.3% of the patients with psoriasis, more frequently in men.[1–4] The 4th finger and 1st toe are most commonly affected by the nail involvement of psoriasis.[4] While pitting and onycholysis are the most prevalent patterns in fingernails, onycholysis, and crumbling are the most frequent toenail changes.[5] It has also been demonstrated that cutaneous psoriasis begins earlier in patients with nail involvement.[4] In most patients, nail involvement occurs after the onset of or simultaneously with skin symptoms. Occasionally, nail involvement can be the only symptom of the disease.[6,7] One of the most commonly used parameters in determining nail psoriasis severity is the Nail Psoriasis Severity Index (NAPSI).[8]

Similar to other areas, psoriasis manifests itself in the form of erythematous squamous plaques on the scalp. However, hair loss is hardly expected even though the pilosebaceous unit is affected.[9–11] Characteristically, the lesions cross the hairline and end with a sharp border.[12] Also, scalp psoriasis can cause severe itching that impairs patients’ quality of life.[13] The Psoriasis Scalp Severity Index (PSSI) is used to determine the severity of scalp involvement.[14]

Psoriatic arthritis (PsA) is considered one of the most critical components of psoriatic disease and significantly affects the disease course. PsA accompanies 6% to 41% of psoriasis patients and usually occurs several years after the onset of skin involvement.[15] Enthesitis, one of the characteristic features of PsA, is seen in 35% of the patients.[16] Dactylitis is another characteristic of PsA and has been encountered in 48% of patients with PsA.[17] Knee, finger, and hip joints are among the most commonly involved joints. In addition, it was demonstrated in a study that 52% of the patients with psoriasis did not have PsA but had arthralgia.[18] Diagnosis of PsA is essential as it might cause irreversible joint damage (e.g., arthritis mutilans) when left untreated. The delay in diagnosis is 5 years on average; thus, it is crucial to have full knowledge of the PsA cues and timely direct the right patient to the comprehensive assessment for arthritis.[18] In this study, we primarily aimed to evaluate whether nail and/or scalp involvements are associated with the presence of PsA and deserve more attention to refer a patient for rheumatological assessment in Turkish psoriasis patients. Also, we wanted to see the prevalence of PsA in Turkish psoriasis patients having nail and/or scalp involvement. Besides nail and scalp involvement, we evaluated the relationship of other covariates with PsA and compared the severity of skin, scalp, and/or nail involvement across the patient groups.

2. Materials and methods

This multicentered cross-sectional study included 763 patients from 11 different centers in Turkey between June 2021 and December 2021. Patients with psoriasis aged ≥ 12 who were not on systemic therapy for 3 months, i.e., at least 3 months after the cessation of the latest systemic drug, and were not actively using topical agents were included. Patients were included in the study regardless of their clinical subtype of psoriasis. Patients who were not provided informed consent were excluded.

The severity of psoriasis involvement of the patients was evaluated using the Psoriasis Area and Severity Index (PASI), PSSI, and NAPSI. The following parameters were also recorded: age, sex, disease duration, family history of psoriasis, body mass index (BMI) (kg/m2), presence/absence of metabolic syndrome, duration without medication, and latest systemic treatment. After an initial assessment in the dermatology department, all patients who describe joint symptoms such as arthralgia, morning stiffness, or swelling were referred to the rheumatology department for evaluation for arthritis. While adult patients were assessed by adult rheumatologists, pediatric rheumatologists assessed pediatric patients. Patients who fulfilled CASPAR criteria were diagnosed as PsA.[19] The primary outcome of this study was the presence of arthritis. The Ethics Committee of Cerrahpasa Faculty of Medicine approved the study (approval number: 178305), and it was conducted per the Declaration of Helsinki. Informed consent was obtained from all patients participating in the study. For patients aged < 18 years, informed consent was received from the parents of patients.

Statistical analyses were performed using the SPSS version 23.0 (IBM Corp., Armonk). The required sample size was calculated for logistic regression analysis at the alpha error level of 0.05 for 80% statistical power (https://www.psychologie.hhu.de/arbeitsgruppen/allgemeine-psychologie-und-arbeitspsychologie/gpower). Descriptive statistics were expressed as numbers and percentages for categorical variables and mean, median, minimum, and maximum for continuous variables. The normality of continuous variables was tested using visual (histogram and probability graphs) and analytical methods (Kolmogorov-Smirnov/Shapiro–Wilk tests). Two group comparisons for categorical variables were performed using the Chi-Square or Fisher’s exact tests where appropriate. Two group comparisons for non-normally distributed continuous variables were performed using the Mann–Whitney U test. Spearman’s rho test was used to test the relationship between continuous variables. The size of the correlation 0.3–0.5 was regarded as a low positive (negative) correlation, 0.5–0.7 moderate positive (negative) correlation, 0.7–0.9 high positive (negative) correlation, and 0.9–1 very high positive (negative) correlation.[20] Univariate and multivariate binary logistic regression analysis was performed to investigate independent factors associated with PsA. Independent variables for regression analysis were determined as age, gender, disease duration, family history of psoriasis (presence/absence), BMI, metabolic syndrome (presence/absence), PASI score, nail involvement (presence/absence), and scalp involvement (presence/absence). Variables found statistically significant in univariate analysis were evaluated by multivariate analysis using forward stepwise method. The statistical significance level was accepted as a P value of < .05.

3. Results

Baseline characteristics of patients are summarized in Table 1. Of these patients, 372 (48.8%) were female and 391 (51.2%) were male. Also, 33 (4%) patients were in the pediatric age group (<18 years old). In all patients with psoriasis, the rate of nail involvement was 55.5%, the rate of scalp involvement was 78.4%, and the rate of both scalp and nail involvement was 42.4%. Among all patients with psoriasis, the proportion of patients with PsA was 21.5% (n = 155), peripheral arthritis being the most common (n = 112, 72.2%). Around half (n = 334, 48.3%) of patients had no systemic therapy, and methotrexate was the most frequent treatment (n = 181, 26.2%) used (Table 2).

Table 1 Baseline characteristics of patients

Features	
Female sex, n (%)	372 (48.8)	
Age, Median (min–max)	39 (13–80)	
BMI, Median (min–max)	25,8 (15.9–59)	
Obesity, n (%)	147 (19.7)	
Family history of psoriasis, n (%)	259 (33.9)	
Metabolic syndrome, n (%)	109 (16.5)	
Disease duration (months), Median (min–max)	120 (1–720)	
Duration without medication (months), Median (min–max)	24 (3–480)	
PASI score, Median (min–max)	6 (0–60)	
NAPSI score, Median (min–max)	3 (0–111)	
Nail involvement (NAPSI > 0), n (%)	415 (55.5)	
PSSI score, Median (min–max)	4 (0–60)	
Scalp involvement (PSSI > 0), n (%)	588 (78.4)	
Nail and scalp involvement (NAPSI > 0&PSSI > 0), n (%)	314 (42.4)	
Arthritis, n (%)	155 (21.5)	
BMI = body mass index, NAPSI = Nail Psoriasis Severity Index, PASI = Psoriasis Area Severity Index, PSSI = Psoriasis Scalp Severity Index.

Table 2 Latest therapies.

Therapies	N (%)	
No systemic therapy	334 (48.3)	
Acitretin	46 (6.7)	
Acitretin + dbUVB	2 (0.3)	
Phototherapy	13 (1.8)	
Isotretinoin	1 (0.1)	
Local injection	1 (0.1)	
Adalimumab	28 (4.1)	
Etanercept	9 (1.3)	
Infliximab	1 (0.1)	
Certolizumab	3 (0.4)	
Corticosteroid	1 (0.1)	
Methotrexate	181 (26.2)	
Methotrexate + Adalimumab	2 (0.3)	
Methotrexate + Acitretin	2 (0.3)	
Methotrexate + Golimumab	1 (0.1)	
Methotrexate + Infliximab	1 (0.1)	
Methotrexate + Ixekizumab	1 (0.1)	
Methotrexate + Cyclosporine	4 (0.6)	
Secukinumab	10 (1.4)	
Ixekizumab	6 (0.9)	
Cyclosporine	22 (3.2)	
Ustekinumab,	21 (3)	
Cyclosporine + Ustekinumab	1 (0.1)	
nbUVB = narrow-band ultraviolet B.

The frequency of PsA was significantly higher in females (63.2% vs 36.8%, P < .001), in patients with a family history of psoriasis (43.2% vs 30.9%, P = .004), and in patients with nail involvement (68.4% vs 52.3%, P < .001). Although the presence of scalp involvement alone was not associated with the increase in the frequency of PsA, the frequency of PsA was found to be significantly higher in the patients with both scalp and nail involvement (53.7 vs 39.6, P = .002). Median disease duration (months) was significantly longer in patients with PsA (126 vs 108, P = .009). Patients with PsA had substantially higher PASI (7 vs 5.6, P = .006), NAPSI (5 vs 2, P < .001), and PSSI scores (7 vs 4, P = .002) (Table 3). In univariate analysis, female gender [OR: 2.41, 95% CI (1.634–3.567), P < .001], family history of psoriasis [OR: 1.87, 95% CI (1.280–2.734), P = .001], BMI [OR: 1.06, 95% CI (1.020–1.102), P = .003], PASI score [OR: 1.03, 95% CI (1.011–1.054), P = .003], and presence of nail involvement [OR: 2.04, 95% CI (1.372–3.032), P < .001] were significant predictors for PsA. Multivariate analysis yielded 3 significant models for predicting PsA; the first: female gender [OR: 2.7, 95% CI (1.719–4.397), P < .001], the second: female gender [OR: 3.05, 95% CI (1.891–4.926), P < .001] and nail involvement [OR: 2.05, 95% CI (1.289–3.263), P = .002], the third:female gender [OR: 3.01, 95% CI (1.861–4.880), P < .001], nail involvement [OR: 2.06, 95% CI (1.293–3.302), P = .002], and BMI [OR: 1.06, 95% CI (1.017–1.100), P = .005] (Table 4).

Table 3 Comparison of baseline features according to presence of psoriatic arthritis.

	Psoriatic arthritis, n = 155	
Present, n (%)	Absent, n (%)	P value	
Female sex, n (%)	98 (63.2)	256 (45.1)	<.001*	
Age, Median (min–max)	41 (13–79)	38 (13–80)	.065	
BMI, Median (min–max)	25.6 (17–59)	25.8 (15.9–47.1)	.255	
Obesity, n (%)	35 (22.7)	105 (18.7)	.262	
Family history of psoriasis, n (%)	67 (43.2)	175 (30.9)	.004*	
Metabolic syndrome, n (%)	26 (20.5)	80 (16.2)	.253	
Disease duration (mo), Median (min–max)	126 (1.5–480)	108 (1–720)	.009*	
Duration without medication (mo), Median (min–max)	24 (1–480)	18 (1.5–480)	.422	
PASI score, Median (min–max)	7 (0.6–60)	5.6 (0–58.5)	.006*	
NAPSI score, Median (min–max)	5 (0–102)	2 (0–111)	<.001*	
Nail involvement (NAPSI > 0), n (%)	104 (68.4)	290 (52.3)	<.001*	
PSSI score, Median (min–max)	7 (0–60)	4 (0–60)	.002*	
Scalp involvement (PSSI > 0), n (%)	117 (78)	443 (79.2)	.739	
Nail and scalp involvement (NAPSI > 0&PSSI > 0), n (%)	80 (53.7)	218 (39.6)	.002*	
BMI = body mass index, NAPSI = Nail Psoriasis Severity Index, PASI = Psoriasis Area Severity Index, PSSI = Psoriasis Scalp Severity Index.

*P < .05.

Table 4 Analysis of predictors for psoriatic arthritis.

Variables	Univariate model	Multivariate model	
Model 1	P value	Model 2	P value	Model 3	P value	
OR	95% CI	P value	OR (95% CI)	OR (95% CI)	OR (95% CI)	
Age	1.01	0.999–1.023	.086	–	–	–	–	–	–	
Gender (female)	2.41	1.634–3.567	<.001***	2.7 (1.719–4.397)	<.001***	3.05 (1.891–4.926)	<.001***	3.01 (1.861–4.880)	<.001***	
Disease duration				–	–	–	–	–	–	
Family history of psoriasis	1.87	1.280–2.734	.001**	–	–	–	–	–	–	
BMI	1.06	1.020–1.102	.003**	–	–	–	–	1.06 (1.017–1.100)	.005**	
Metabolic syndrome	1.58	0.959–2.627	.072	–	–	–	–	–	–	
PASI score	1.03	1.011–1.054	.003**	–	–	–	–	–	–	
Nail involvement	2.04	1.372–3.032	<.001***	–	–	2.05 (1.289–3.263)	.002**	2.06 (1.293–3.302)	.002**	
Scalp involvement	0.95	0.604–1.510	.845	–	–	–	–	–	–	
BMI = body mass index, CI = confidence interval, OR = odds ratio, PASI = psoriasis area severity index.

** P < .01,

*** P < .001.

Subgroup analysis of patients with nail involvement revealed that the frequency of nail involvement was higher in males than in females (56.6% vs 43.4%, P < .001). Patients with nail involvement were significantly older (41 vs 37, P = .009) and had longer disease duration (months) (120 vs 84, P < .001). Also, patients with nail involvement had considerably higher PASI scores than patients without nail psoriasis (8.35 vs 4.85, P < .001) (Table 5). In the subgroup analysis of patients with scalp involvement, it was found that those with scalp involvement were significantly younger (37 vs 45, P < .001) and had higher PASI scores (6.9 vs 4.5, P < .001) (Table 6). Furthermore, the coexistence of nail and scalp involvement was more frequent among males (57.3% vs 42.7, P = .003), and these patients had substantially longer disease duration (132 vs 90, P < .001) and higher PASI scores (10 vs 4.8, P < .001) (Table 7). The difference between PASI, NAPSI, and PSSI scores in the patients with and without a family history of psoriasis was not significant (6,25 vs 6, P = 554, 2 vs 3, P = 970, and 4 vs 5, P = .943, respectively).

Table 5 Comparison of baseline features according to presence of nail involvement.

	Nail involvement, n = 415	
Present, n (%)	Absent, n (%)	P value	
Female sex, n (%)	180 (43.4)	185 (55.6)	.001*	
Age, Median (min–max)	41 (13–80)	37 (13–79)	.009*	
BMI, Median (min–max)	25.6 (16.6–44.54)	25,91 (15.9–47.1)	.823	
Obesity, n (%)	82 (20)	61 (18.9)	.709	
Family history of psoriasis, n (%)	142 (34.2)	114 (34.2)	.996	
Metobolic syndrome, n (%)	68 (18.7)	40 (13.5)	.074	
Disease duration (months), Median (min–max)	120 (3–720)	84 (1–480)	<.001*	
Duration without medication (months), Median (min–max)	24 (3–480)	15 (1–480)	.056	
PASI score, Median (min–max)	8.35 (0–60)	4.85 (0–39)	<.001*	
PSSI score, Median (min–max)	4 (0–60)	4 (0–54)	.618	
Scalp involvement, (PSSI > 0), n (%)	314 (76.8)	265 (79.8)	.318	
BMI = body mass index, PASI = Psoriasis Area Severity Index, PSSI = Psoriasis Scalp Severity Index.

*P < .05.

Table 6 Comparison of baseline features according to presence of scalp involvement.

	Scalp involvement, n = 588	
Present, n (%)	Absent, n (%)	P value	
Female sex, n (%)	285 (48.5)	81 (50)	.730	
Age, Median (min–max)	37 (13–80)	45 (13–78)	<.001*	
BMI, Median (min–max)	25.6 (15.9–59)	26 (15.9–47.1)	.267	
Obesity, n (%)	112 (19.4)	32 (20.4)	.793	
Family history of psoriasis, n (%)	201 (34.2)	54 (33.3)	.840	
Metobolic syndrome, n (%)	83 (16.2)	25 (17.1)	.786	
Disease duration (months), Median (min–max)	120 (1–720)	120 (1.5–600)	.895	
Duration without medication (months), Median (min–max)	24 (1–480)	24 (1–480)	.895	
PASI score, Median (min–max)	6.9 (0.1–60)	4.5 (0–38.7)	<.001*	
NAPSI score, Median (min–max)	3 (0–111)	4 (0–78)	.648	
BMI = body mass index, NAPSI = Nail Psoriasis Severity Index, PASI = Psoriasis Area Severity Index.

*P < .05.

Table 7 Comparison of baseline features according to nail and scalp involvement.

	Nail and scalp involvement, n = 314	
Present, n (%)	Absent, n (%)	P value	
Female sex, n (%)	134 (42.7)	229 (53.6)	.003*	
Age, Median (min–max)	38.5 (13–80)	39 (13–79)	.527	
BMI, Median (min–max)	25.55 (17–42)	26 (15.9–47.1)	.475	
Obesity, n (%)	57 (18,4)	83 (20)	.601	
Family history of psoriasis, n (%)	109 (34.7)	144 (33.7)	.779	
Metobolic syndrome, n (%)	50 (17.7)	57 (15.2)	.376	
Disease duration (mo), Median (min–max)	132 (3–720)	90 (1–600)	<.001*	
Duration without medication (mo), Median (min–max)	24 (3–480)	13 (1–480)	.049*	
PASI score, Median (min–max)	10 (0.5–60)	4.8 (0–39)	<.001*	
BMI = body mass index, PASI = Psoriasis Area Severity Index.

*P < .05.

A significant but weak positive correlation existed between PASI score, disease duration, and BMI (r = 0.158, P < .001 and r = 0.099, P = .013, respectively). BMI and disease duration were weakly correlated with NAPSI score (r = 0.094, P = .024 and r = 0.147, P < .001, respectively). Also, age showed a weak positive correlation with PASI (r = 0.141, P < .001) and NAPSI (r = 0.135, P < .001) scores and a weak negative correlation with PSSI score (r = −0.087, P = .017).

4. Discussion

In this study, it was found that the prevalence of PsA was significantly higher in psoriasis patients who had nail involvement and coexistence of nail and scalp involvement. Female gender, the presence of nail involvement, and high BMI were significant independent predictors for PsA in multivariate analysis. Female gender has been identified as the strongest predictor for PsA in the Turkish psoriasis patient population. Also, psoriasis patients with joint involvement showed substantially higher skin and nail involvement scores, i.e., PASI, NAPSI, and PSSI.

Accurate prediction of PsA based on skin involvement patterns and demographic characteristics will facilitate clinical decision-making and lead to studies on the prevention of PsA. Furthermore, prediction of the PsA is vital for the patient’s quality of life as PsA will cause irreversible joint deformity and various comorbidities when left untreated for a long time.[21]

PsA may affect male and female patients in different ways and may show sex-related differences in clinical presentation, disease course, and response to treatment. Most studies demonstrate that peripheral PsA is more common in females. In contrast, axial PsA, radiographic arthritis, and severe psoriasis are more common among males, highlighting the need for specific sex-gender considerations in diagnosis and treatment selection. On the other hand, female patients with PsA have worse quality of life, functional status, and compliance with treatment.[22] In our study, PsA was more prevalent in females, and being female was the most important factor in increasing the probability of being diagnosed with PsA. To our knowledge, no study has shown that the female gender is an independent and significant predictor of PsA. This condition may be related to the genetic characteristics of Turkish society and the fact that the disease has become more dominant in females in recent years.[22] However, our study did not examine gender differences regarding PsA subtypes and severity.

There are different results regarding PsA predictors in the literature, and the focus is on the relationship between nail and scalp involvement and PsA. Patrizi et al[23] proposed that nail psoriasis is a suggestive feature of PsA, whereas scalp psoriasis and intergluteal/perianal psoriatic lesions are less associated with PsA. An extensive retrospective analysis of 4146 patients from 3 independent national cross-sectional studies revealed that nail involvement and inpatient hospital treatment were the strongest predictors for PsA.[24] In a study by Yan et al, while age, nail involvement, scalp involvement, skin fold involvement, elbow/knee involvement, psoriasis severity, hypertension, and type 2 diabetes were found positively associated with PsA, nail involvement, type 2 diabetes, and pustular psoriasis remained significantly associated with PsA in multivariate analysis.[25] In a survey of 1633 patients followed for 30 years, scalp lesions, nail dystrophy, and intergluteal/perianal lesions were found to be associated with a higher risk of PsA.[26] A systematic review investigating the prevalence of psoriasis and PsA across and within specific regions of Italy showed that PsA prevalence was highest in patients with nail and/or scalp psoriasis and/or intergluteal/perianal region involvement.[27] A recent meta-analysis of 26 cohort studies demonstrated that psoriasis severity, nail pitting, high categories of BMI, and family history of PsA were predictors for PsA.[21] Also, a systematic review and meta-analysis of 16 observational studies showed that the risk of PsA was higher in obese and overweight people, with an OR of 1.75 (95% CI, 1.42–2.16) and OR 1.50 (95% CI, 1.08–2.09), respectively.[28] In our research, nail involvement and high BMI were significant predictors of PsA, consistent with the literature. However, we found no significant relationship between the severity of psoriasis and PsA. PASI scores may have been lower than expected in some patients due to the prolonged effect of systemic therapies beyond 3 months in our study.

Additionally, our study did not find scalp involvement as a factor associated with PsA. On the other hand, a randomized controlled study evaluating the relationship between scalp psoriasis and PsA severity concluded that scalp involvement was not associated with PsA severity and did not affect treatment response.[29] We attribute the association of scalp involvement with PsA in some of the studies mentioned above primarily to the effect of racial and environmental factors and the difference in study designs.[23,26,27] Therefore, conducting studies involving patients from different nations would be helpful in understanding the issue better.

It has recently been suggested that there is interconnection between the systemic inflammation caused by metabolic syndrome and PsA.[30,31] Considering the effect of nutritional styles on psoriatic disease, we think that the reason we did not find PsA to be associated with metabolic syndrome in our study may be related to the dietary habits of Turkish society.[32–34] On the other hand, in our study, there was a significant positive correlation between PASI scores and BMI, which was consistent with the literature.[32] Furthermore, our study showed that a family history of psoriasis was positively associated with PsA in univariate analysis. Similar to our research, some studies link the family history of psoriasis with PsA.[35,36] It is important to note, unlike our study, these studies scrutinized the effects of family history of psoriasis on psoriasis and PsA characteristics rather than evaluating family history as a predictor of PsA.[35,36] A recent systematic review and meta-analysis showed that a family history of PsA was a predictor for PSA but did not include a family history of skin psoriasis in the analysis.[21]

The present study has some limitations. Since this is a multicentric study, different physicians evaluated the patients. The heterogeneous group includes not only different centers but also patients of different ages, and this is the most important limitation. Because data from a sufficient number of patients could not be obtained, information about the human leukocyte antigen alleles of the patients could not be reported. Additionally, stratification according to PsA severity and clinical subtypes of psoriasis/PsA could not be made. Nevertheless, this study includes a large number of patients from the same nation. Therefore, it reflects the general status of Turkish psoriasis patients.

5. Conclusion

In this study, female gender, nail involvement, and high BMI were determined to be independent PsA predictors, with the female gender being the strongest predictor. Therefore, patients carrying one or more of these risk factors warrant comprehensive rheumatological assessment. Moreover, PsA is associated with more severe skin involvement scores (PASI, NAPSI, and PSSI). Understanding underlying pathogenesis leading to associations between skin and musculoskeletal findings of psoriatic disease is a subject of future study, possibly paving the way for developing better and wiser therapeutic strategies.

Acknowledgments

The authors disclose that they did not have any writing assistance. The authors would like to thank Omega Contact Research Organization for their assistance with statistical analysis.

Author contributions

Conceptualization: Ozge Askin, Burhan Engin, Server Serdaroglu.

Data curation: Tumay Ak.

Formal analysis: Tumay Ak.

Investigation: Ozge Askin, Burhan Engin, Ayse Ozdede, Selda Pelin Kartal, Serdal Ugurlu, Tugba Ozkok Akbulut, Algun Polat Ekinci, İbrahim Halil Aydogdu, Muge Guler Ozden, Huseyin Kok, Sibel Dogan, Serap Ozturkcan, Murat Borlu, Emel Bulbul Baskan, Nazan Yilmaz, Zeynep Topkarci.

Methodology: Ozge Askin, Server Serdaroglu.

Project administration: Ayse Ozdede, Server Serdaroglu.

Resources: Ozge Askin.

Supervision: Burhan Engin, Server Serdaroglu.

Writing – review & editing: Tumay Ak.

Abbreviations:

BMI body mass index

CI confidence interval

NAPSI Nail Psoriasis Severity Index

OR odds ratio

PASI Psoriasis Area Severity Index

PsA psoriatic arthritis

PSSI Psoriasis Scalp Severity Index

The authors have no funding and conflicts of interest to disclose.

The datasets generated during and/or analyzed during the current study are not publicly available, but are available from the corresponding author on reasonable request.

How to cite this article: Askin O, Engin B, Ozdede A, Kartal SP, Ugurlu S, Akbulut TO, Ekinci AP, Aydogdu İH, Ozden MG, Kok H, Dogan S, Ozturkcan S, Borlu M, Baskan EB, Yilmaz N, Ak T, Topkarci Z, Serdaroglu S. Relationship of psoriatic arthritis with nail and scalp involvement in Turkish psoriasis patients: Multicentered cross-sectional study. Medicine 2024;103:29(e38832).
==== Refs
References

[1] Salomon J Szepietowski JC Proniewicz A . Psoriatic nails: a prospective clinical study. J Cutan Med Surg. 2003;7 :317–21.12879333
[2] Armesto S Esteve A Coto-Segura P . Nail psoriasis in individuals with psoriasis vulgaris: a study of 661 patients. Actas Dermosifiliogr. 2011;102 :365–72.21514549
[3] Rachakonda TD Schupp CW Armstrong AW . Psoriasis prevalence among adults in the United States. J Am Acad Dermatol. 2014;70 :512–6.24388724
[4] Augustin M Reich K Blome C Schäfer I Laass A Radtke MA . Nail psoriasis in Germany: epidemiology and burden of disease. Br J Dermatol. 2010;163 :580–5.20456340
[5] Brazzelli V Carugno A Alborghetti A . Prevalence, severity and clinical features of psoriasis in fingernails and toenails in adult patients: Italian experience. J Eur Acad Dermatol Venereol. 2012;26 :1354–9.21973119
[6] Rigopoulos D Tosti A eds. Nail Psoriasis: From A to Z. Springer; 2014.
[7] Jiaravuthisan MM Sasseville D Vender RB Murphy F Muhn CY . Psoriasis of the nail: anatomy, pathology, clinical presentation, and a review of the literature on therapy. J Am Acad Dermatol. 2007;57 :1–27.17572277
[8] Mease PJ . Measures of psoriatic arthritis: Tender and Swollen Joint Assessment, Psoriasis Area and Severity Index (PASI), Nail Psoriasis Severity Index (NAPSI), Modified Nail Psoriasis Severity Index (mNAPSI), Mander/Newcastle Enthesitis Index (MEI), Leeds Enthesitis Index (LEI), Spondyloarthritis Research Consortium of Canada (SPARCC), Maastricht Ankylosing Spondylitis Enthesis Score (MASES), Leeds Dactylitis Index (LDI), Patient Global for Psoriatic Arthritis, Dermatology Life Quality Index (DLQI), Psoriatic Arthritis Quality of Life (PsAQOL), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), Psoriatic Arthritis Response Criteria (PsARC), Psoriatic Arthritis Joint Activity Index (PsAJAI), Disease Activity in Psoriatic Arthritis (DAPSA), and Composite Psoriatic Disease Activity Index (CPDAI). Arthritis Care Res (Hoboken). 2011;63 (Suppl 11 ):S64–85.22588772
[9] Headington JT Gupta AK Goldfarb MT . A morphometric and histologic study of the scalp in psoriasis. Paradoxical sebaceous gland atrophy and decreased hair shaft diameters without alopecia. Arch Dermatol. 1989;125 :639–42.2637673
[10] Shuster S . Psoriatic alopecia. Br J Dermatol. 1972;87 :73–7.5043203
[11] Rittié L Tejasvi T Harms PW . Sebaceous gland atrophy in psoriasis: an explanation for psoriatic alopecia? J Invest Dermatol. 2016;136 :1792–800.27312025
[12] Chuong CM Dhouailly D Gilmore S . What is the biological basis of pattern formation of skin lesions? Exp Dermatol. 2006;15 :547–64.16761964
[13] Farber EM Nall L . Natural history and treatment of scalp psoriasis. Cutis. 1992;49 :396–400.1628504
[14] Alsenaid A Ezmerli M Srour J Heppt M Illigens BM Prinz JC . Biologics and small molecules in patients with scalp psoriasis: a systematic review. J Dermatolog Treat. 2022;33 :473–82.32406275
[15] Ogdie A Weiss P . The epidemiology of psoriatic arthritis. Rheum Dis Clin North Am. 2015;41 :545–68.26476218
[16] Terslev L Naredo E Iagnocco A .; Outcome Measures in Rheumatology Ultrasound Task Force. Defining enthesitis in spondyloarthritis by ultrasound: results of a Delphi process and of a reliability reading exercise. Arthritis Care Res (Hoboken). 2014;66 :741–8.24151222
[17] Coates LC Hodgson R Conaghan PG Freeston JE . MRI and ultrasonography for diagnosis and monitoring of psoriatic arthritis. Best Pract Res Clin Rheumatol. 2012;26 :805–22.23273793
[18] Lebwohl MG Kavanaugh A Armstrong AW Van Voorhees AS Van Voorhees AS . US perspectives in the management of psoriasis and psoriatic arthritis: patient and physician results from the population-based Multinational Assessment of Psoriasis and Psoriatic Arthritis (MAPP) Survey. Am J Clin Dermatol. 2016;17 :87–97.26718712
[19] Taylor W Gladman D Helliwell P Marchesoni A Mease P Mielants H ; CASPAR Study Group. Classification criteria for psoriatic arthritis: development of new criteria from a large international study. Arthritis Rheum. 2006;54 :2665–73.16871531
[20] Mukaka MM . Statistics corner: a guide to appropriate use of correlation coefficient in medical research. Malawi Med J. 2012;24 :69–71.23638278
[21] Zabotti A De Lucia O Sakellariou G . Predictors, risk factors, and incidence rates of psoriatic arthritis development in psoriasis patients: a systematic literature review and meta-analysis. Rheumatol Ther. 2021;8 :1519–34.34596875
[22] Tarannum S Leung YY Johnson SR . Sex- and gender-related differences in psoriatic arthritis. Nat Rev Rheumatol. 2022;18 :513–26.35927578
[23] Patrizi A Venturi M Scorzoni R Pazzaglia M Malavolta N Bardazzi F . Nail dystrophies, scalp and intergluteal/perianal psoriatic lesions: risk factors for psoriatic arthritis in mild skin psoriasis? G Ital Dermatol Venereol. 2014;149 :177–84.24819637
[24] Langenbruch A Radtke MA Krensel M Jacobi A Reich K Augustin M . Nail involvement as a predictor of concomitant psoriatic arthritis in patients with psoriasis. Br J Dermatol. 2014;171 :1123–8.25040629
[25] Yan D Ahn R Leslie S Liao W . Clinical and genetic risk factors associated with psoriatic arthritis among patients with psoriasis. Dermatol Ther (Heidelb). 2018;8 :593–604.30343350
[26] Wilson FC Icen M Crowson CS McEvoy MT Gabriel SE Kremers HM . Incidence and clinical predictors of psoriatic arthritis in patients with psoriasis: a population-based study. Arthritis Rheum. 2009;61 :233–9.19177544
[27] Prignano F Rogai V Cavallucci E Bitossi A Hammen V Cantini F . Epidemiology of psoriasis and psoriatic arthritis in Italy – a systematic review. Curr Rheumatol Rep. 2018;20 :43.29846817
[28] Xie W Huang H Deng X Gao D Zhang Z . Modifiable lifestyle and environmental factors associated with onset of psoriatic arthritis in patients with psoriasis: A systematic review and meta-analysis of observational studies. J Am Acad Dermatol. 2021;84 :701–11.32827608
[29] De Vlam K Mallbris L Szumski A Jones H . Limited association between scalp psoriasis and psoriatic arthritis severity and treatment response. Clin Exp Rheumatol. 2017;35 :141–4.27606545
[30] Cigolini C Fattorini F Gentileschi S Terenzi R Carli L . Psoriatic arthritis: one year in review 2022. Clin Exp Rheumatol. 2022;40 :1611–9.36129799
[31] Caso F Chimenti MS Navarini L . Metabolic Syndrome and psoriatic arthritis: considerations for the clinician. Expert Rev Clin Immunol. 2020;16 :409–20.32149545
[32] Barros G Duran P Vera I Bermúdez V . Exploring the links between obesity and psoriasis: a comprehensive review. Int J Mol Sci . 2022;23 :7499.35886846
[33] Katsimbri P Korakas E Kountouri A . The effect of antioxidant and anti-inflammatory capacity of diet on psoriasis and psoriatic arthritis phenotype: nutrition as therapeutic tool? Antioxidants (Basel). 2021;10 :157.33499118
[34] Gisondi P Fostini AC Fossà I Girolomoni G Targher G . Psoriasis and the metabolic syndrome. Clin Dermatol. 2018;36 :21–8.29241748
[35] Liu H Lu C Yang F .; Chinese Registry of Psoriatic Arthritis (CREPAR). Associations between family history of psoriatic disease and clinical characteristics on patients with psoriatic arthritis: a nationwide study from the Chinese Registry of Psoriatic Arthritis (CREPAR II). Clin Exp Rheumatol. 2023;41 :1901–7.37199179
[36] Solmaz D Bakirci S Kimyon G . Impact of having family history of psoriasis or psoriatic arthritis on psoriatic disease. Arthritis Care Res (Hoboken). 2020;72 :63–8.30680951
