==== Front BMC Emerg Med BMC Emerg Med BMC Emergency Medicine 1471-227X BioMed Central London 387 10.1186/s12873-020-00387-y Research Article Characteristic patterns of emergency ambulance assignments for older adults compared with adults requiring emergency care at home in Sweden: a total population study http://orcid.org/0000-0002-5758-7610Hjalmarsson Anna anna.hjalmarsson@mdh.se 1 Holmberg Mats 234 Asp Margareta 1 Östlund Gunnel 1 Nilsson Kent W. 15 Kerstis Birgitta 1 1 grid.411579.f0000 0000 9689 909XSchool of Health, Care and Social Welfare, Mälardalen University, Eskilstuna Västerås, Sweden 2 grid.8148.50000 0001 2174 3522Faculty of Health and Life Sciences, Linneaus University, Växjö, Sweden 3 grid.8993.b0000 0004 1936 9457Centre for Clinical Research Sörmland, Uppsala University, Eskilstuna, Sweden 4 Department of Ambulance Service, Region Sörmland, Eskilstuna, Sweden 5 grid.8993.b0000 0004 1936 9457Centre for Clinical Research Västerås, Uppsala University, Västmanland County Hospital, Västerås, Sweden 2 12 2020 2 12 2020 2020 20 942 6 2020 16 11 2020 © The Author(s) 2020Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.Background Since the vast majority of older adults in Sweden live in their private homes throughout life, the emergency medical services need to adapt accordingly. Hence, we aimed to describe characteristic patterns of dyadic staffed emergency ambulance assignments for older adults aged > 70 years compared with adults aged 18–69 years requiring emergency care at home in Sweden. Methods A descriptive retrospective study was performed using anonymized registry data from the emergency medical services in a region of Sweden during 2017–2018. One-sample χ2 test, one-way analysis of variance, and binary logistic regression models were used for investigating group differences. Variables for analysis were age, gender, clinical assessments, on-scene time, priority levels, result of response, and temporal patterns. Results Of all included emergency ambulance assignments (n = 28,533), 59.9% involved older adults, of which 53.8% were women. The probability for older adults to receive the highest priority was decreased for both dispatch (p < 0.001, odds ratio [OR] 0.63, 95% confidence interval [CI] 0.59–0.66), and transport priorities (p < 0.001, OR 0.74, 95% CI 0.68–0.80). Older adults were more likely to receive dispatch priority levels 2 (p < 0.001, OR 1.48, 95% CI 1.40–1.56), and 3 (p < 0.001, OR 1.73, 95% CI 1.46–2.06). The older adults were similarly more likely to receive transport priority level 3 (p < 0.001, OR 1.40, 95% CI 1.28–1.52) compared with adults. Age had a small but additive effect in relation to on-scene time (p < 0.001, R2 = 0.01, F = 53.82). Distinguishing initial clinical assessments for older adults were circulatory, respiratory, trauma, infection, and nonspecific assessments. Emergency ambulance assignments for older adults were more frequently occurring on Mondays (p < 0.001, χ2 = 232.56), and in the 08:00–11:59 interval (p < 0.001, χ2 = 1224.08). Conclusion The issues of the lower priority level preponderance, and the decreased probability for receiving the highest priority warrant further attention in future research and clinical practice. Keywords AmbulanceCharacteristicsEmergency medical servicesOlder adultsissue-copyright-statement© The Author(s) 2020 ==== Body Background There is an ongoing shift in population demographics worldwide, from younger to older age [1]. Therefore, the World Health Organization strongly recommends that health care systems globally redesign their services to better fulfill older people’s needs and to promote their independence [1]. Older age entails prevalence of cognitive and physical impairments, chronic medical conditions, and frailty, thus increasing the need for emergency ambulance care [2–6]. Currently, approximately 1.5 million people in Sweden are aged > 70 years [7], a population that is estimated to rise by 25% over the next 15 years [8]. In addition, the population of the current 0.5 million people aged > 80 years [7] is estimated to rise by 61% in the same period [8]. Life expectancy in Sweden is high compared with many other countries. A global ranking places Sweden 11th [9] with an average life expectancy of 84.7 years for women and 81.3 years for men [10]. By 2060, the life expectancies of Swedish women and men are estimated to reach 89.1 and 86.7 years respectively [11]. Due to targeted political governance, the vast majority of older adults live in their own private homes throughout life, only about 80,000 older adults live in nursing homes [12]. Hence, the emergency needs of the older adult population living at home will substantially impact future ambulance care. The Swedish emergency medical services (EMS) providing emergency ambulance care are regulated by law, which states that high-quality care is to be provided to all, assuring safety, equality, and patient participation [13, 14]. Swedish EMS personnel are the frontline providers of this stated care and include primarily registered nurses with a bachelor’s degree and specialist nurses with postgraduate education within, for example, prehospital, anesthetic, or intensive care (henceforth, registered and specialist nurses are referred to as RNs). The Swedish EMS RNs have an autonomous prehospital medical and caring responsibility, requiring specialist competence [15]. The context of prehospital emergency care is complex, and the RNs need to adjust to organizational requirements of rapid responses and available care options in relation to the patient’s medical or personal needs, and safety [15]. The prehospital assessment is based on very limited background information, and entails considerations of risks versus benefits influenced by the EMS RN’s competence, experience, organizational support, and guidelines [16, 17]. The EMS RNs carry out an initial clinical assessment of the patient’s symptoms and emergency need on scene, to determine the adequate level of emergency care and transport priority if conveyance to hospital is deemed necessary. The options for level of care are limited in Sweden, and generally include conveyance to hospital or leaving the older adult at home. Older adults are challenging to clinically assess, often displaying low acuity conditions [18, 19] or atypical or masked symptoms due to conditions such as polypharmacy, dementia, or chronic diseases [20]. The prehospital assessment and the level of care provided, plays a paramount role for the health outcome of older adults. Previous research focusing on older adults receiving ambulance care reported such assignments to be prolonged compared with those for younger adults [21], and that conveyance rates were high [5, 21]. An Australian study reporting temporal patterns of ambulance demand for community dwelling older adults, found that such calls peaked on Mondays around 11:00 and were more frequent in the Australian winter and spring [5]. A Swedish study of EMS assignments for older adults found that such adults were more frequently assessed as having nonspecific conditions, and that age and gender influenced the assessments [22]. Swedish EMS research targeting specific emergency needs of the increasing population of older adults living at home is however scarce. This study provides an understanding of prevalent emergency ambulance assignments for older adults living at home in Sweden. Since the Swedish EMS is a statutory welfare service, defined to be safe, equal, and of high quality for all, it is of likewise importance to describe potential inequalities between populations. Such knowledge would further enable interventions beneficial for older adults, in accordance with the legislative liability of the EMS. To identify characteristics representative of assignments for older adults, we performed a comparative analysis between older adults and the general adult population. Hence, the overall study aim was to describe characteristic patterns of dyadic staffed emergency ambulance assignments for older adults aged > 70 years compared with adults aged 18–69 years requiring emergency care at home. Age group differences in the following were investigated: age and gender frequency; result of response; priority levels; clinical assessments; on-scene time; and temporal patterns. Methods Study design The present study had a descriptive 2-year range retrospective design. Registry data from the Swedish EMS in the region of Sörmland was analyzed, comprising all EMS assignments from January 2017 to December 2018. Ethical approval was obtained by the Swedish Ethical Review Authority (Dnr: 2019–02027), and access permission to anonymized registry data was provided by the manager of the EMS in the region. Study setting The region included in this study is one of 21 regions in Sweden. This medium-sized region (ca. 6000 km2) is situated southwest of Stockholm, and consists of nine municipalities covering rural and urban areas. The region has a population of approximately 300,000 inhabitants, with 85% of them living in urban areas [23]. Approximately 17% of the inhabitants are older adults aged > 70 years, of which 54% are women [24]. The EMS of the region cover six ambulance stations, each located in one of the six largest municipalities. On weekdays, the EMS have at their disposal 16 daytime (08:00–18:00) emergency ambulance vehicle units and 11 nighttime (18:00–08:00) units. At weekends, 13 and 10 vehicles are available, respectively. Swedish EMS personnel mainly work in dyads, and besides RNs, emergency medical technicians (EMTs) mainly trained as assistant nurses are a common part of the team [25]. All dyadic staffed emergency ambulances in Sweden are considered advanced life support (ALS) units [15], and the RNs are licensed for drug administration [25]. Single responder ambulances have been implemented in the Swedish EMS, managed by one RN alone and not used for conveyance [26]. The Swedish EMS utilize the Rapid Emergency Triage and Treatment System (RETTS©) as an instrument for triage [27]. EMS physicians mainly serve as medical advisors, and are not part of the ambulance team [25]. Three descending levels of emergency are used for prioritizing EMS assignments by the emergency medical communication centers (EMCC) receiving medical emergency calls: 1) life-threatening or possibly life-threatening; 2) not life-threatening, requiring advanced care and conveyance; and 3) not life-threatening, advanced care and conveyance required within a reasonable time [28]. Level 1 is a high priority level indicating unstable vital signs, and levels 2 and 3 are considered lower priority levels indicating stable vital signs. Swedish health care is part of a welfare system financed by the regions through income taxes and government support. The cost for EMS responses is settled by the regions. In the region of the present study, ambulance responses are free of charge for citizens aged 0–19 and > 85 years and subsidized for other citizens (ca. €37/US$41 per response). Study population The data comprise all assignments performed by the EMS (N = 75,088) in 2017–2018. The final sample (n = 28,533) for analysis represents primary dyadic staffed ALS emergency ambulance assignments for adults requiring emergency care at home, resulting in conveyance or nonconveyance, with entries made in clinical records for possible calculation of on-scene time (Fig. 1). In the present study, older adults are defined as those aged > 70 years, and adults as aged 18–69 years. This age cutoff has been previously used in similar research [29]. Fig. 1 Flow chart of final sample. The sample (n = 28,533) represents primary dyadic staffed emergency ambulance assignments for adults and older adults requiring emergency care at home, resulting in conveyance or nonconveyance Variables for analysis A total of seven assignment variables were processed for analysis: age, gender, result of response, priority levels, on-scene time, clinical assessments, and temporal patterns. Age was analyzed as a continuous variable or stratified into two age groups: adults (18–69 years) and older adults (70–104 years). Age was additionally stratified into eight age groups for one-way analysis of variance, and for visual display of responses in relation to age (18–29, 30–39, 40–49, 50–59, 60–69, 70–79, 80–89, and 90–104 years). The dichotomous age group variable is used as the main predictor in the logistic regression models. Result of response is denoted as conveyance (transport to hospital) or nonconveyance (remain at home). The variable is used as outcome, and as predictor in other logistic regression models. Dispatch priority denotes the priority level assigned to the EMS response by the EMCC receiving the medical emergency call. Transport priority denotes the priority level assigned to the patient by the EMS RNs when conveyed to hospital. The three priority levels were dichotomized for binary logistic regression modeling: level 1/level 2 or 3, level 2/level 1 or 3, and level 3/level 1 or 2. The level 1/level 2 or 3 variable is used as predictor in other logistic regression models. The clinical assessments in the registry data encompassed 134 assessments entered by the EMS RNs. These assessments were clustered into 14 categories in accordance with the emergency signs and symptoms (ESS) grouping used by the EMS in the region [27]. Of the 14 categories, two were without any clinical assessment (transfer, other) and therefore presented as missing cases. For analysis using binary logistic regression, the assessments were dichotomized (assessment/all other assessments). The variable is used as outcome, and as predictor in other logistic regression models. Ambulance on-scene time denotes the time in minutes spent in the home of the adults and older adults or in the ambulance on the scene, ranging from 1 to 235 min. The variable was calculated by subtracting ambulance arrival time from departure time, in consensus with the registry manager of the EMS. The variable is used for one-way analysis of variance and as predictor in the logistic regression models. Temporal patterns were categorized into three time periods: diurnal, weekly, and seasonal. The diurnal variable was further divided into two or six periods of time: 08:00–17:59 (daytime) and 18:00–07:59 (nighttime) in accordance with the EMS ambulance disposition, and in 4-h intervals: 00:00–03:59, 04:00–07:59, 08:00–11:59, 12:00–15:59, 16:00–19:59, and 20:00–23:59. The weekly variables were stratified into two or seven time periods: weekdays (Monday–Friday) and weekend (Saturday–Sunday), and each day of the week. The seasonal variable was stratified into four categories: winter (December–February), spring (March–May), summer (June–August), and autumn (September–November). The variable is used in one-sample χ2 test, and the dichotomous daytime/nighttime variable is used as predictor in the logistic regression models, referred to as time of day. Statistical analysis Descriptive statistics are presented using frequencies and percentages for categorical variables and using means and standard deviations for continuous variables. Nonparametric variable correlations were analyzed using one-sample χ2 test, and one-way analysis of variance was used for age and on-scene time correlations, with supplementary Scheffe’s post hoc for between group multiple comparison. Binary logistic regression models were used to analyze the dichotomized outcome variables priority level, result of response, and initial clinical assessment. The chosen predictor variables were discussed among the researchers, and considered to be of importance for the outcome variables. A p-value < 0.05 was considered statistically significant. All analyses were performed using IBM SPSS Statistics (version 24.0; IBM SPSS, Armonk, NY, USA). Results Of the 28,533 included dyadic staffed emergency ambulance assignments to private homes in the region during 2017–2018, 17,097 (59.9%) involved older adults aged > 70 years (mean = 81.3, standard deviation = 7.0, range = 70–104 years), of which 53.8% were women. In relation to age, there was a considerable increase in assignments for older adults aged 70–79 and 80–89 years (Fig. 2). Fig. 2 Dyadic staffed emergency ambulance assignments to private homes in the region of Sörmland in Sweden 2017–2018, stratified by age groups Older adults were more likely to be conveyed to hospital compared to the adult population (p < .001, adjusted odds ratio [adjOR] 1.79, 95% confidence interval [CI] 1.33–2.40) (Table 2), the conveyance rate being 89.4% within the older adult age group compared with 82.6% in the adult age group (Table 1). In the adult population, 46.0% received the highest priority, in contrast to only 37.3% in the older adult group (Table 1). The likelihood for older adults to receive the highest priority level was reduced for both dispatch (p < .001, adjOR 0.63, 95% CI 0.59–0.66), and transport priorities (p < .001, adjOR 0.74, 95% CI 0.68–0.80) (Table 2). The probability for receiving a dispatch priority level 2 (p < .001, adjOR 1.48, 95% CI 1.40–1.56) or 3 (p < .001, adjOR 1.73, 95% CI 1.46–2.06) was increased for the older adults (Table 2), constituting 59.9 and 2.7% of the older adults compared with 52.1 and 1.9% in the adult population (Table 1). The older adult group were similarly more likely to receive a transport priority level 3 (p < .001, adjOR 1.40, 95% CI 1.28–1.52) compared with the adults (Table 2). The proportion of transport priority level 2 were similar in both age groups, 72.9% of the adults and 73.1% of the older adults received priority level 2, and there was no difference in odds ratio (Table 2). Table 1 Characteristics of emergency ambulance assignments for adults and older adults at home in Sweden Age group Adults (18–69) n = 11,436 Older adults (70–104) n = 17,097 Age (years)  Mean (SD) 48.9 (15.3) 81.3 (7.0)  Male (SD) 50.5 (14.9) 80.5 (6.6)  Female (SD) 47.5 (15.5) 81.9 (7.3)  Median 52 81  Male 54 80  Female 49 82 Gender n (% within group)a  Male 5364 (47.0) 7901 (46.2)  Female 6041 (53.0) 9191 (53.8) Result of response n (% within group)  Conveyance 9443 (82.6) 15,279 (89.4)  Non-conveyance 1993 (17.4) 1818 (10.6) Priority level n (% within group)b  Dispatch priority level 1 5256 (46.0) 6382 (37.3)  Dispatch priority level 2 5961 (52.1) 10,247 (59.9)  Dispatch priority level 3 219 (1.9) 468 (2.7)  Transport priority level 1 1391 (14.6) 2045 (13.3)  Transport priority level 2 6956 (72.9) 11,239 (73.1)  Transport priority level 3 1199 (12.6) 2098 (13.6) aMissing cases: gender; adults 31, older adults 5 bPatients receiving transport priority without recorded entries of conveyance; adults 103, older adults 103 Descriptive statistics presented for age, gender, result of response, and priority level variables. Percentage in brackets display within group proportion Table 2 Priority levels and result of response for older adults at home in Sweden Adults (18–69) n = 11,436 Older adults (70–104) n = 17,097 Unadjusted Adjusted Priority level Age group (% within group) p OR (95% CI) p OR (95% CI) Dispatch Priority level 1 Adults (46.0) Ref Ref Older adults (37.3) < .001 0.70 (0.67–0.74) < .001 0.63 (0.59–0.66) Dispatch priority level 2 Adults (52.1) Older adults (59.9) < .001 1.37 (1.31–1.44) < .001 1.48 (1.40–1.56) Dispatch priority level 3 Adults (1.9) Older adults (2.7) < .001 1.44 (1.23–1.70) < .001 1.73 (1.46–2.06) Transport priority level 1 Adults (14.6) Older adults (13.3) .005 0.90 (0.84–0.97) < .001 0.74 (0.68–0.80) Transport priority level 2 Adults (72.9) Older adults (73.1) .740 1.01 (0.95–1.07) .820 0.99 (0.93–1.06) Transport priority level 3 Adults (12.6) Older adults (13.6) .016 1.10 (1.02–1.19) < .001 1.40 (1.28–1.52) Result of response Conveyance Adults (82.6) Older adults (89.4) < .001 1.77 (1.66–1.90) < .001 1.79 (1.33–2.40) Binary logistic regression models for priority level and result of response variables presented as unadjusted, and adjusted odds ratios (OR) with 95% confidence interval (CI). Independent variables adjusted for in the priority level models are gender, initial clinical assessment, on-scene time, result of response and time of day. Independent variables adjusted for in the result of response model are gender, initial clinical assessment, on-scene time, priority level and time of day. Percentage in brackets displays proportion within age group. Significant adjusted odds ratios differentiating the older adult group are highlighted in bold text Circulatory, respiratory, trauma, infection, and nonspecific assessments were predominant in the older adult age group, and the probability for all assessments but circulatory and trauma were more than doubled (Table 3). Eye, ear, nose and throat assessments had a similar increased likelihood, but represented only 1.1% of the assessments within the age group. Table 3 Initial clinical assessments for adults and older adults at home in a region of Sweden Adults (18–69) n = 11,436 Older adults (70–104) n = 17,097 Unadjusted Adjusted Initial clinical assessmenta Age group n (%) p OR (95% CI) p OR (95% CI) Circulatory (e.g. chest pain, cardiac arrest/dysrhythmia, hypertension) Adults 1997 (17.5) .240 Ref Ref Older adults 2894 (16.9) 0.96 (0.91–1.03) .023 1.09 (1.01–1.17) Eye, ear, nose, throat (e.g. bleeding, pain, foreign body) Adults 64 (0.6) Older adults 190 (1.1) < .001 2.00 (1.50–2.65) < .001 2.60 (1.86–3.65) Genital (gynecology, urology) Adults 194 (1.7) Older adults 292 (1.7) .941 1.01 (0.84–1.21) 302 1.11 (0.91–1.36) Infection Adults 581 (5.1) Older adults 1732 (10.1) < .001 2.11 (1.91–2.32) < .001 2.05 (1.84–2.27) Medical (e.g. anemia, diabetic symptoms, Addison’s disease, immune deficiency) Adults 1109 (9.7) Older adults 1189 (7.0) < .001 0.70 (0.64–0.76) < .001 0.63 (0.57–0.70) Neurology (e.g. stroke, headache, seizure, loss of consciousness, dizziness) Adults 1952 (17.1) Older adults 2727 (16.0) .012 0.92 (0.87–0.98) .120 0.95 (0.88–1.01) Nonspecific Adults 216 (1.9) Older adults 673 (3.9) < .001 2.13 (1.83–2.49) < .001 2.08 (1.73–2.50) Orthopedic (e.g. musculoskeletal pain) Adults 585 (5.1) Older adults 824 (4.8) .255 0.94 (0.84–1.05) < .001 0.71 (0.63–0.81) Psychiatric (e.g. psychiatric disorders, suicidality, anxiety, drug abuse) Adults 520 (4.5) Older adults 194 (1.1) < .001 0.24 (0.20–0.29) < .001 0.21 (0.17–0.26) Respiratory (e.g. respiratory distress, dyspnea, hyperventilation) Adults 731 (6.4) Older adults 2232 (13.1) < .001 2.20 (2.02–2.40) < .001 2.41 (2.19–2.66) Surgical (e.g. gastrointestinal hemorrhage, abdominal pain, nausea/vomiting) Adults 1740 (15.2) Older adults 1654 (9.7) < .001 0.60 (0.55–0.64) < .001 0.58 (0.54–0.68) Trauma (physical injury) Adults 1075 (9.4) Older adults 1998 (11.7) < .001 1.28 (1.18–1.38) .023 1.10 (1.01–1.20) aPatients not receiving initial clinical assessment; adults 672, older adults 498 Binary logistic regression models for each assessment presented as unadjusted, and adjusted odds ratios (OR) with 95% confidence interval (CI). Independent variables adjusted for in the models are gender, on-scene time, priority level, result of response and time of day. Adjusted odds ratios characterizing initial clinical assessments for older adults are highlighted in bold text. The proportion of adults and older adults receiving the assessment within the age group is displayed as n (%) Figure 3 displays the impact of age on emergency ambulance on-scene time. Age had a small although additive effect in relation to on-scene time (p < 0.001, R2 = 0.01, F = 53.82). The p-values displayed in Fig. 3, indicate age groups with significantly longer on-scene time. Fig. 3 Mean and 95% confidence interval for emergency ambulance on-scene time using one-way analysis of variance, and Scheffe’s post hoc. Age groups having significant longer on-scene time are displayed with p-values in the figure Age group differences were found in all temporal variables (Table 4). Compared to the adult population, emergency ambulance assignments for older adults were more frequent during daytime, and in the 08:00–11.59 interval (Fig. 4). An older adult preponderance was additionally found on weekdays, on Mondays (Fig. 4), and in the winter. Table 4 Temporal patterns of emergency ambulance assignments for adults and older adults at home in Sweden Age group Adults (18–69) n = 11,436 Older adults (70–104) n = 17,097 p χ2 Diurnal patterns n (% within group)  00:00–03.59 1661 (14.5) 1547 (9.0) .044 4.05  04:00–07.59 1182 (10.3) 1882 (11.0) < .001 159.92  08:00–11.59 2074 (18.1) 5021 (29.4) < .001 1224.08  12:00–15.59 2002 (17.5) 3480 (20.4) < .001 398.48  16:00–19.59 2167 (18.9) 2904 (17.0) < .001 107.11  20:00–23.59 2350 (20.5) 2263 (13.2) .200 1.64  08:00–17.59 (daytime) 5087 (44.5) 9887 (57.8) < .001 1538.67  18:00–07.59 (nighttime) 6349 (55.5) 7210 (42.2) < .001 54.67 Weekly patterns n (% within group)  Monday 1631 (14.3) 2626 (15.4) < .001 232.56  Tuesday 1629 (14.2) 2483 (14.5) < .001 177.36  Wednesday 1580 (13.8) 2455 (14.4) < .001 189.75  Thursday 1579 (13.8) 2390 (14.0) < .001 165.72  Friday 1575 (13.8) 2473 (14.5) < .001 199.21  Saturday 1678 (14.7) 2268 (13.3) < .001 88.22  Sunday 1764 (15.4) 2382 (13.9) < .001 97.71  Weekday 7994 (69.9) 12,427 (72.7) < .001 962.32  Weekend 3442 (30.1) 4670 (27.3) < .001 185.90 Seasonal patterns n (% within group)  Winter (Dec-Feb) 2845 (24.9) 4428 (25.9) < .001 344.55  Spring (Mars-May) 2860 (25.0) 4284 (25.1) < .001 283.84  Summer (June-Aug) 3093 (27.0) 4287 (25.1) < .001 193.18  Autumn (Sep-Nov) 2638 (23.1) 4098 (24.0) < .001 316.45 One-sample χ2 test investigating age group proportion in relation to number of assignments. Percentage in brackets display within group proportion. The χ2 values highlighted in bold text are the variables displaying the highest differences between the age groups Fig. 4 Temporal patterns of emergency ambulance assignments for adults and older adults at home, in the region of Sörmland in Sweden 2017–2018 The differences were similarly found in a one-sample χ2 test of within group variations (not shown in table). Assignments for adults were increasing in the afternoon, being most frequent in the evening between 20:00–23.59 (p < 0.001, χ2 = 465.32). Assignments within the older adult group were found less than expected in all intervals apart from 08:00–11.59, 12:00–15.59, and 16:00–19.59, the greatest difference found in the forenoon (p < 0.001, χ2 = 2839.96). Assignments for the older adults were found more than expected during daytime (p < 0.001, χ2 = 419.16) and in weekdays (p < 0.001, χ2 = 3519.39), compared to the adults that were found more than expected during nighttime (p < 0.001, χ2 = 139.27), and in the weekends (p < 0.001, χ2 = 1811.88). Assignments for older adults were found more than expected in all days of the week, apart from Thursdays, Saturdays and Sundays, and most frequent on Mondays (p < 0.001, χ2 = 29.17). In contrast, assignments for the adult population were less than expected all week apart from Saturdays and Sundays, most frequently occurring on Sundays (p = 0.008, χ2 = 17.32). In the seasonal variable, assignments for the older adults were more frequent in the winter, spring, and summer, being most frequent in the winter (p = 0.005, χ2 = 12.859). Assignments for the adult population were most frequent in the summer (p < 0.001, χ2 = 36.30). Discussion The aim of the present study was to describe characteristic patterns of dyadic staffed emergency ambulance assignments for older adults aged > 70 years compared with adults aged 18–69 years requiring emergency care at home. The main finding was the preponderance of lower priority levels in the older adult group, in addition to a decreased probability of them receiving the highest priority compared with the adult age group. The reason for this finding might be indicative of the complexity and challenges related to assessing the emergency needs of older adults. Masked symptoms due to polypharmacy, cognitive decline or even natural bodily changes clouds the clinical picture, and make critical conditions hard to detect [20]. In addition, underlying societal tendencies of ageism might be a contributing factor, which are currently being addressed by the World Health Organization to increase the knowledge and competence of health care providers worldwide [1]. Furthermore, the RETTS©, based on vital signs and cutoff points, has been criticized for not being able to differentiate between stable and unstable patients [30]. Swedish EMS RNs report feeling alone in the assessment process, being uncertain about making the right decision, in fear of harming the patient [31]. Another Swedish study similarly concluded that decisions of nonconveyance were difficult and involved a great responsibility [32]. The lack of organizational support, and the risk of being held liable if the wrong decision is made are factors influencing EMS personnel’s decisions [16, 33]. However, a recent review by Yeung et al. [34] found decisions of nonconveyance to be relatively safe for patients. Further attention needs to be paid to why older adults receive lower priorities. In the present study, 89.4% of the older adults were conveyed to hospital. Conveyance is however not always a suitable option. A major reason for conveyance is the lack of options that results in inadequate transportations to overcrowded emergency departments (EDs) [18, 35]. Frail older adults, being physically intolerant and vulnerable to acute illnesses, do not adapt well to the busy environment at the ED [36]. Moreover, older adults are more likely to have longer waiting times in an ED than younger adults [37, 38]. ED admittance also implies an increased risk for missed diagnoses, delirium, infection [39], pressure ulcers [40], and defaulted care [41–43]. Conveyance of older adults assessed as having low or no acuity might however also be representative of patient participation, the EMS personnel being responsive to the patient’s requests and preferences when deciding about care [17, 44]. In perceived emergency situations, an individual is authorized to call for an ambulance, even for low acuity conditions [45]. Similar to the present case, the problem of a lack of options apart from ED conveyance exists in many countries. A Japanese study [18] suggested focusing on primary care and expanding primary clinic office hours. An Australian study evaluating the establishment of an “acute geriatric outreach service” reported positive results regarding patient safety [46]. In Sweden, older adults expressed satisfaction when offered admittance to a geriatric ward instead of traditional conveyance to EDs when possible, due to previous negative experiences of ED admittance [41]. Shared decision-making was similarly pointed out as beneficial for improving EMS care for older adults in the US [47]. In addition, a possibility for the EMS personnel to consult a physician decreased unnecessary conveyance for low acuity patients in Sweden [48]. In Sweden, mortality is high due to circulatory diseases such as heart failure [11], with the cause of death primarily being related to prior morbidity. The predominance of circulatory clinical assessments in both age groups, provides further support for this finding, implying a future substantial impact on the EMS. Respiratory as well as trauma and nonspecific clinical assessments are reported as being distinctive to older adults worldwide [5, 18, 49, 50]. In the present study, psychiatric assessments were highly associated with the adult age group. This finding is in accordance with Vloet et al. [51], who related behavioral, mental, and neurodevelopmental disorders more frequently to younger nonconveyed patients. However, it can be speculated that psychiatric conditions in older adults become more obscure, meaning that more salient chronic physical conditions are easier to assess. A US study of older adults (aged 55–93 years) found that chronic conditions such as heart or respiratory diseases relate to higher self-reports of depressive symptoms [52]. A recent review focusing on suicidal behavior in older adults concluded that functional disabilities and somatic illness were contributing factors [53]. Concerning the extended on-scene time, research indicates that the clinical complexity of older adults prolongs the overall EMS response time [35, 54]. Harmsen et al. [55] related prolonged on-scene time to more comprehensive care, and additionally suggested a future emphasis on prehospital emergency care, rather than focusing on rapid transportation to EDs. The clinical implications of our findings require further investigation. The actual difference in on-scene time between the youngest and oldest adult groups of patients was around 4.5 min. This finding raises the question whether it is representative of more comprehensive care, or merely a representation of cognitive and functional impairments of older adults prolonging the on-scene time. The present study found that emergency ambulance assignments for older adults at home were more frequently occurring on Mondays and in the 08:00–11:59 time interval, in accordance with Australian studies [5, 56]. The frequency of assignments on Mondays might be related to home care visits. Fewer visits on the weekends, as well as a greater number of temporary personnel, might prevent the detection of emerging acuity needs. Another reason for this finding may be knowledge about less resources being available on the weekends, making waiting until Monday an option to optimize care. More research is necessary to elucidate the causes underlying this pattern. Limitations Although the relatively large population used for analysis in the present study implies greater statistical power and trustworthiness, some limitations should be noted. The data processed for analysis are dependent on the accuracy of the medical records entered by the EMS RNs. Some relevant data might therefore have been missed due to some inconsistencies in medical records. Because all registry data were anonymized, the possibility of recognizing repeated ambulance transports of the same individual was excluded. It was also not possible to cross-reference community records to identify the number of older adults requiring ambulance care who also utilized home care service, which would have strengthened this study. Another limitation is the lack of causality of the frequent level 2 priorities. This will be further explored in upcoming studies, based on interviews with EMS personnel and older adults. Since the initial clinical assessment is primarily based on symptoms and vital signs, the assessment might not be consonant with the final ED diagnose. The potential divergence might result in inaccurate clinical data. However, the assessments are anchored in the everyday reality of EMS RNs, and are the results of existing prerequisites, limitations, and competence. Another limitation concerns the evaluation of the logistic regression analysis, and the models’ goodness of fit. In large datasets, the Hosmer-Lemeshow statistics displays deficits. However, the large sample size per se and the robustness of binary logistics might verify the models. Finally, the results of the present study might not be generalizable to other countries, populations, or age groups, although the use of a relatively large sample from the general population allows for broad generalizability to similar contexts. Conclusion Emergency ambulance assignments for older adults at home in a region of Sweden were characterized by a lower priority level preponderance, and a decreased probability for receiving the highest priority. Older adults were more likely to be conveyed, and differentiating initial clinical assessments were circulatory, respiratory, trauma, infection, and nonspecific assessments. Age had an additive effect in relation to on-scene time, and assignments for older adults at home were more frequently occurring during weekdays, on Mondays, and in the 08:00–11:59 interval. Considering the projected increase in the older adult population, the identified patterns may be of use in EMS resource allocation. Health care policy makers need to acknowledge the complex reality of the context, and design adequate and flexible levels of emergency care beneficial to older adults. The issue of the identified priority level divergence warrant further attention in future research, education and clinical practice. Abbreviations adjORAdjusted odds ratio ALSAdvanced life support CIConfidence interval EDEmergency department EMCCEmergency medical communication center EMSEmergency medical services EMTEmergency medical technician OROdds ratio RETTSRapid emergency triage and treatment system RNRegistered nurse Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Acknowledgements We wish to thank Patric Bränderson at the Department of Ambulance Services, Region Sörmland, for his excellent support in providing access to registry data. Authors’ contributions Study design (AH, MH, MA, GÖ, BK). Data collection (AH, MH). Data-analysis (AH, KN, BK). Manuscript preparation (AH, MH, MA, GÖ, KN, BK). All authors read and approved the final manuscript. Funding There was no funding body involved. Open Access funding provided by Malardalen Hogskola. Availability of data and materials The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. Ethics approval and consent to participate Ethical approval was obtained by the Swedish Ethical Review Authority (Dnr: 2019–02027), and access permission to anonymized registry data was provided by the manager of the EMS of the region. Consent for publication Not applicable. Competing interests The authors declare that they have no competing interests. ==== Refs References 1. World Health Organization. World report on ageing and health 2015: https://www.who.int/ageing/events/world-report-2015-launch/en/. Accessed 30 Mar 2020. 2. Platts-Mills TF Leacock B Cabanas JG Shofer FS McLean SA Emergency medical services use by the elderly: analysis of a statewide database Prehosp Emerg Care 2010 14 3 329 333 10.3109/10903127.2010.481759 20507220 3. Jones CMC Wasserman EB Li T Amidon A Abbott M Shah MN The effect of older age on EMS use for transportation to an emergency department Prehosp Disaster Med 2017 32 3 261 268 10.1017/S1049023X17000036 28190410 4. Dwyer R Gabbe B Tran TD Smith K Lowthian JA Patterns of emergency ambulance use, 2009-13: a comparison of older people living in residential aged care facilities and the community Age Ageing 2018 47 4 615 619 10.1093/ageing/afy056 29688243 5. Cantwell K Morgans A Smith K Livingston M Dietze P Differences in emergency ambulance demand between older adults living in residential aged care facilities and those living in the community in Melbourne, Australia Australas J Ageing 2017 36 3 212 221 10.1111/ajag.12413 28480623 6. Evans CS Platts-Mills TF Fernandez AR Grover JM Cabanas JG Patel MD Repeated emergency medical services use by older adults: analysis of a comprehensive statewide database Ann Emerg Med 2017 70 4 506 515.e503 10.1016/j.annemergmed.2017.03.058 28559037 7. Statistics Sweden. Population by age and sex: http://www.statistikdatabasen.scb.se/pxweb/sv/ssd/START__BE__BE0101__BE0101A/BefolkningR1860/. Accessed 23 Mar 2020. 8. Statistics Sweden. Population by region of birth, age and sex. Year 2019–2120: http://www.statistikdatabasen.scb.se/pxweb/sv/ssd/START__BE__BE0401__BE0401A/BefolkprognRevN/. Accessed 30 Mar 2020. 9. Infoplease Life expectancy for countries 2020 10. Statistics Sweden Medellivslängden i Sverige [life expectancy in Sweden] 2020 11. Statistics Sweden Hög medellivslängd i Sverige [high life expectancy in Sweden] 2017 12. Swedish National Board of Health and Welfare Statistik om socialtjänstinsatser till äldre [statistics about social services to older adults] 2018 13. SFS 2017:30. Hälso- och sjukvårdslagen [the health and medical services care act]. 2017. Stockholm: Socialdepartementet [Ministry of health and social affairs].. 14. SFS 2014:821. Patientlagen [the patient safety act]. 2014. Stockholm: Socialdepartementet [Ministry of health and social affairs]. 15. Suserud BO Lundberg L Prehospital akutsjukvård [Prehospital emergency care] 2016 2 Stockholm Liber 16. Ebben RHA Vloet LCM Speijers RF Tönjes NW Loef J Pelgrim T A patient-safety and professional perspective on non-conveyance in ambulance care: a systematic review Scand J Trauma Resusc Emerg Med 2017 25 1 71 10.1186/s13049-017-0409-6 28716132 17. Jones CMC Cushman JT Lerner EB Fisher SG Seplaki CL Veazie PJ Prehospital trauma triage decision-making: a model of what happens between the 9-1-1 call and the hospital Prehosp Emerg Care 2016 20 1 6 14 10.3109/10903127.2015.1025157 26017368 18. Horibata K Takemura Y Inappropriate use of ambulance services by elderly patients with less urgent medical needs Tohoku J Exp Med 2015 235 2 89 95 10.1620/tjem.235.89 25742927 19. Durant E Fahimi J Factors associated with ambulance use among patients with low-acuity conditions Prehosp Emerg Care 2012 16 3 329 337 10.3109/10903127.2012.670688 22494108 20. Shenvi CL Platts-Mills TF Managing the elderly emergency department patient Ann Emerg Med 2019 73 3 302 307 10.1016/j.annemergmed.2018.08.426 30287120 21. Duong HV Herrera LN Moore JX Donnelly J Jacobson KE Carlson JN National characteristics of emergency medical services responses for older adults in the United States Prehosp Emerg Care 2018 22 1 7 14 10.1080/10903127.2017.1347223 28862480 22. Magnusson C Herlitz J Axelsson C Patient characteristics, triage utilisation, level of care, and outcomes in an unselected adult patient population seen by the emergency medical services: a prospective observational study BMC Emerg Med 2020 20 1 7 10.1186/s12873-020-0302-x 32000684 23. Statistics Sweden Urban areas (localities) 2018 24. Statistics Sweden. Population by region, marital status, age and sex. Year 1968–2019: http://www.statistikdatabasen.scb.se/pxweb/en/ssd/START__BE__BE0101__BE0101A/BefolkningNy/.Accessed 17 Apr 2020. 25. Lindström V Bohm K Kurland L Prehospital care in Sweden Notfall + Rettungsmedizin 2015 18 2 107 109 10.1007/s10049-015-1989-1 26. Carlström E Fredén L The first single responders in Sweden – evaluation of a pre-hospital single staffed unit Int Emerg Nurs 2017 32 15 19 10.1016/j.ienj.2016.05.003 27282963 27. Widgren BR Jourak M Medical emergency triage and treatment system (METTS): a new protocol in primary triage and secondary priority decision in emergency medicine J Emerg Med 2011 40 6 623 628 10.1016/j.jemermed.2008.04.003 18930373 28. SOSFS 2009:10. Socialstyrelsens författningssamling. Ambulanssjukvård. [the national board of health and welfare. Code of statues. Prehospital emergency care]. 2009. Stockholm: Socialstyrelsen. 29. Lowthian J Curtis A Stoelwinder J McNeil J Cameron P Emergency demand and repeat attendances by older patients Intern Med J 2013 43 554 560 10.1111/imj.12061 23279076 30. Wireklint SC Elmqvist C Parenti N Göransson KE A descriptive study of registered nurses´ application of the triage scale RETTS©; a Swedish reliability study Int Emerg Nurs 2018 38 21 28 10.1016/j.ienj.2017.12.003 29326039 31. Lederman J Löfvenmark C Djärv T Lindström V Elmqvist C Assessing non-conveyed patients in the ambulance service: a phenomenological interview study with Swedish ambulance clinicians BMJ Open 2019 9 e030203 10.1136/bmjopen-2019-030203 32. Höglund E Schröder A Möller M Andersson-Hagiwara M Ohlsson-Nevo E The ambulance nurse experiences of non-conveying patients J Clin Nurs 2018 00 1 10 10.1111/jocn.14626 33. Oosterwold J Sagel D Berben S Roodbol P Broekhuis M Factors influencing the decision to convey or not to convey elderly people to the emergency department after emergency ambulance attendance: a systematic mixed studies review BMJ Open 2018 8 e021732 10.1136/bmjopen-2018-021732 34. Yeung T Shannon B Perillo S Nehme Z Jennings P Olaussen A Review article: outcomes of patients who are not transported following ambulance attendance: a systematic review and meta-analysis Emerg Med Australas 2019 31 321 331 10.1111/1742-6723.13288 30943579 35. O'Hara R Johnson M Siriwardena AN Weyman A Turner J Shaw D A qualitative study of systemic influences on paramedic decision making: care transitions and patient safety J Health Serv Res Policy 2015 20 45 53 10.1177/1355819614558472 36. SBU [Swedish Council on Health Technology Assessment] Omhändertagande av äldre som inkommer akut till sjukhus – med fokus på sköra äldre 2013 Stockholm Statens beredning för medicinsk utvärdering (SBU) 37. Bunn JG Croft SJ O’Keeffe C Jacques RM Simpson RM Stone T Urgent care axis for the older adult: where is best to target interventions? Emerg Med J 2019 36 22 26 10.1136/emermed-2018-207505 30177504 38. Kennelly SP Drumm B Coughlan T Collins R O’Neill D Romero-Ortuno R Characteristics and outcomes of older persons attending the emergency department: a retrospective cohort study Q J Med 2014 107 977 987 10.1093/qjmed/hcu111 39. Hwang U Morrison RS The geriatric emergency department J Am Geriatr Soc 2007 55 11 1873 1876 10.1111/j.1532-5415.2007.01400.x 17916122 40. Dugaret E Videau MN Faure I Gabinski C Bourdel-Marchasson I Salles N Prevalence and incidence rates of pressure ulcers in an emergency department Int Wound J 2014 11 386 391 10.1111/j.1742-481X.2012.01103.x 23043304 41. Vicente V Castren M Sjöstrand F Wireklint SB Elderly patients' participation in emergency medical services when offered an alternative care pathway Int J Qual Stud Health Well-being 2013 8 20014 10.3402/qhw.v8i0.20014 23445898 42. Bridges J Flatley M Meyer J Older people's and relatives’ experiences in acute care settings: systematic review and synthesis of qualitative studies Int J Nurs Stud 2010 47 89 107 10.1016/j.ijnurstu.2009.09.009 19854441 43. Olofsson P Carlström ED Back-Pettersson S During and beyond the triage encounter: chronically ill elderly patients' experiences throughout their emergency department attendances Int Emerg Nurs 2012 20 207 213 10.1016/j.ienj.2012.03.006 23084509 44. Barrientos C Holmberg M The care of patients assessed as not in need of emergency ambulance care - registered nurses' lived experiences Int Emerg Nurs 2018 38 10 14 10.1016/j.ienj.2018.01.007 29433812 45. Booker MJ Purdy S Shaw ARG Seeking ambulance treatment for 'primary care' problems: a qualitative systematic review of patient, carer and professional perspectives BMJ Open 2017 7 e016832 10.1136/bmjopen-2017-016832 46. Chan DKY Liu FX Irwanto D Prasetyo D Ozorio G Li F Experience of establishing an acute geriatric outreach service versus subacute service to nursing homes Intern Med J 2018 48 1396 1399 10.1111/imj.14104 30387300 47. Hogan TM Richmond NL Carpenter CR Biese K Hwang U Shah MN Shared decision making to improve the emergency Care of Older Adults: a research agenda Acad Emerg Med 2016 23 12 1386 1393 10.1111/acem.13074 27561819 48. Larsson G Holmen A Ziegert K Early prehospital assessment of non-urgent patients and outcomes at the appropriate level of care: a prospective exploratory study Int Emerg Nurs 2017 32 45 49 10.1016/j.ienj.2017.02.003 28291697 49. Yip WL Fan KL Lui CT Leung LP Ng F Tsui KL Utilization of the Accident & Emergency Departments by Chinese elderly in Hong Kong World J Emerg Med 2015 6 283 288 10.5847/wjem.j.1920-8642.2015.04.006 26693263 50. Christensen EF Bendtsen MD Larsen TM Jensen FB Lindskou TA Holdgaard HO Trends in diagnostic patterns and mortality in emergency ambulance service patients in 2007-2014: a population-based cohort study from the North Denmark region BMJ Open 2017 7 e014508 10.1136/bmjopen-2016-014508 51. Vloet LCM de Kreek A van der Linden EMC van Spijk JJA Theunissen VAH van Wanrooij M A retrospective comparison between non-conveyed and conveyed patients in ambulance care Scand J Trauma Resusc Emerg Med 2018 26 91 10.1186/s13049-018-0557-3 30373652 52. Mills TL Comorbid depressive symptomatology: isolating the effects of chronic medical conditions on self-reported depressive symptoms among community-dwelling older adults Soc Sci Med 2001 53 569 578 10.1016/S0277-9536(00)00361-0 11478537 53. Fässberg MM Cheung G Canetto SS Erlangsen A Lapierre S Lindner R A systematic review of physical illness, functional disability, and suicidal behaviour among older adults Aging Ment Health 2016 20 166 194 10.1080/13607863.2015.1083945 26381843 54. Voss S Brandling J Taylor H Black S Buswell M Cheston R How do people with dementia use the ambulance service? A retrospective study in England: the HOMEWARD project BMJ Open 2018 8 e022549 10.1136/bmjopen-2018-022549 55. Harmsen AMK Giannakopoulos GF Moerbeek PR Jansma EP Bonjer HJ Bloemers FW The influence of prehospital time on trauma patients outcome: a systematic review Injury 2015 46 602 609 10.1016/j.injury.2015.01.008 25627482 56. Cantwell K Burgess S Morgans A Smith K Livingston M Dietze P Temporal trends in falls cases seen by EMS in Melbourne: the effect of residence on time of day and day of week patterns Injury 2016 47 266 271 10.1016/j.injury.2015.10.073 26626807