Synergism of an Urgent Care Walk-in Clinic With an Emergency Department

A Pre–Post Comparative Study

Background: The overutilization of hospital emergency departments by low-urgency patients is seen as a growing problem in health-care delivery, and a variety of solutions are under discussion. We studied the change in utilization of a hospital emergency department (ED) by low-urgency patients after an urgent care walk-in clinic (WIC) was opened in the immediate vicinity.

Methods: A prospective, single-center pre–post comparative study was carried out at the University Medical Center Hamburg-Eppendorf (UKE). The ED patient collective consisted of adult walk-in patients who presented to the ED between 4 pm and midnight. The “pre” period consisted of August and September 2019, and the “post” period was from November 2019 (after the opening of the WIC) to January 2020.

Results: The study patients consisted of 4765 ED walk-in patients and 1201 WIC patients. 956 (80.5%) of the WIC patients had been referred onward to the WIC after initially presenting to the ED; from this group, 790 patients (82.6%) received definitive care in the WIC. The number of outpatients treated in the ED fell by 37.3% (95% confidence interval [30.9; 43.8]), from 851.5 to 536.7 per month. The most marked decreases were in the areas of dermatology (from 62.5 to 14.3 patients per month), neurology (45.5 to 25), ophthalmology (115 to 64.7), and trauma surgery (211 to 128.7). No decrease was seen in urology, psychiatry, or gynecology. For patients presenting without any referral document, the mean length of stay fell by a mean of 17.6 [7.4; 27.8] minutes from its “pre” value of 172.3 minutes. The rate of patients who left during treatment fell from 76.5 to 28.3 patients per month (p < 0.001).

Conclusion: A GP-led urgent care walk-in clinic next door to an interdisciplinary hospital emergency department is a resource-saving treatment option for walk-in patients who present to the emergency department. Most of the patients referred from the ED to the WIC were able to receive definitive care there.

Many emergency departments worldwide are seeing a steady rise in patient numbers (1) (e1), which can lead to overcrowded waiting areas, long treatment times, and an increase in premature discontinuation of treatment. Increased mortality among emergency department patients as a result of delays in urgent care or treatment errors have been described to be consequences of this rise (1, 2, 3, 4, e1, e2, e3, e4).

International studies assume inappropriate utilization of emergency departments, with the reported figures varying significantly between countries (3, 5, 6, e5, e6). It has been suggested that a large proportion of emergency department patients with low-urgency health problems could be treated by office-based physicians or a primary care emergency service (3, 4, 5, 6, 7, 8, e6, e7, e8). In particular the complaints of patients presenting on their own initiative and without prior contact with a physician (referred to as self-referrals) often fall within the treatment spectrum of primary care. Expanding the treatments offered in emergency departments by general practitioners has been discussed as a solution aimed at reducing inappropriate visits (9, 10, e9). Similarly in the German health care context, low-urgency patients have been identified as an important factor in the overutilization of emergency departments (7, 8, 11, 12, 13).

International studies have already shown that the integration of general practitioners into emergency departments or co-located urgent care walk-in clinics that operate out of hours and, in particular, treat low-urgency patients reduces the proportion of self-referring patients as well as the overutilization of emergency departments and results in greater cost efficiency, lower treatment and waiting times, and higher patient satisfaction (14, 15, 16, 17, 18, 19, 20, 21, e10).

On the other hand, it has been postulated that this type of provision of care could generate provider-induced demand, meaning that the intended easing of utilization either fails to materialize or declines over time (17, 22, 23). Not all studies published to date show positive effects for general practitioners on emergency department utilization. However, differences between health care systems in the various countries make a comparative assessment challenging (23, 24, 25, 26, e11).

At the University Medical Center Hamburg-Eppendorf (UKE), Germany, general practitioners have been deployed since 2012 in the hospital emergency department (ED) at the UKE to treat low-urgency patients (9, e12). In October 2019, an urgent care walk-in clinic (WIC) belonging to the German National Association of Statutory Health Insurance Physicians (Kassenärztliche Vereinigung, KV) was opened in the immediate vicinity of the ED. This enabled the provision of general medical care to low-urgency patients between 4 pm and midnight. Since then, it has been possible to refer patients there from the ED registration desk during WIC operating hours without the patients being admitted to the ED.

This study investigated the following research questions: To what extent does the low-threshold option to refer patients onwards to a WIC located in the hospital building result in changes to case numbers and treatment times in an ED? What are the patient flows between ED and WIC in this setting?

Methods

Study design and setting

We conducted a prospective, monocentric pre–post comparative study on the utilization of a WIC located in rooms next door to the ED. As a maximum-care hospital, the UKE annually provides care to a total of more than 70,000 adult patients in its ED. The physicians on duty in the ED are assigned by the respective medical departments. ED patients (ED-Ps) are primarily assigned to a speciality.

The study period was from August to September 2019 (“pre” period) and November 2019 to January 2020 (inclusive) (“post” period following the opening of the WIC). In view of the fact that October 2019 was the WIC’s first month in operation, it was considered as a run-in phase and not included in the analysis.

The existing treatment services that had been offered by general practitioners in the ED since 2012 (daily 10 am–6 pm; weekends/public holidays 10 am–4 pm) were extended to 6 pm–midnight (weekends/public holidays 4 pm to midnight) when the WIC was opened. Since then, it has been possible for nursing staff at the ED registration desk to refer low-urgency patients onwards to the WIC.

During its opening hours, the WIC uses the unused rooms of an outpatient clinic (registration desk, three treatment rooms) in the same hospital building and located 25 m away from the ED. The WIC is manned exclusively by general practitioners as well as medical assistants. The available instrument-based tests include ECG, urine test strips, and point-of-care rapid tests (troponin, D-dimers, C-reactive protein [CRP]). If necessary, patients can be referred to the ED.

Participant recruitment

Recruitment took place daily between 4 pm and midnight. Adult walk-in patients capable of giving consent who had been admitted for treatment to the ED were included, as were adult patients of the WIC that had either been referred from the ED or who presented directly to the WIC. Patients that had been brought to the ED by emergency services or internal hospital transport, as well as minors, were excluded. Other reasons for exclusion included, for example, a significant language barrier (for recruitment history, see Figure 1).

Figure 1

Recruitment history in the hospital emergency department and in the urgent care walk-in clinic

All patients that were suitable for inclusion received written study information and the study consent form in either German or English. ED-Ps that required prompt treatment following an initial assessment were asked at a later point in the course of their treatment to participate. Participants recruited in the ED gave their written consent for their treatment data from the UKE electronic medical records to be evaluated.

Data collection

On admission to the WIC, sociodemographic and procedural data (transferral from the ED versus direct presentation, length of stay) were recorded using a pseudonymized questionnaire. Treatment diagnoses and referrals to the ED were additionally obtained with a pseudonymized medical questionnaire.

On admission to the ED, triage level (Manchester triage system) as well as the type of presentation (self-referral or referral by office-based physicians or walk-in clinic belonging to the KV) were noted. Following the completion of treatment, sociodemographic and procedural data (type of presentation, treatment times, level of urgency, treating specialties), as well as data on treatment course (inpatient admission, outpatient treatment, premature treatment discontinuation, discharge diagnoses), were extracted from patients’ medical records and pseudonymized.

The ED specialties general surgery, neurosurgery, oral and maxillofacial surgery, vascular surgery, as well as cardiothoracic surgery were grouped under the category “surgical specialties.” As the specialty with the most patients, trauma surgery was dealt with separately. We defined treatment time as the time from ED admission to the time of printing out the medical discharge letter from the electronic medical records, which as a rule defines the completion of treatment of ED-Ps.

ICD-10 discharge diagnoses were converted to the International Classification of Primary Care (ICPC), second edition, using online translation tables (e13). Equivocal classifications (< 2% of cases) were re-coded by two study authors (BB and JHO) by consensus after a review of the discharge reports. Furthermore, anonymized secondary data on ED patient numbers from previous years (2016‒2020) were evaluated.

Statistical analysis was performed using SPSS26. Data were analyzed by inferential statistics using unpaired t-tests and Chi square tests. The study was reviewed by the Ethics Committee of the Hamburg Medical Association (Ärztekammer Hamburg) on 23.07.2019 (No. PV-7035).

Results

Figure 1 shows the recruitment history. In the “pre” and “post” period, a total of 10,176 ED-Ps were recorded, of which 5528 met the inclusion criteria. Of the walk-in ED-Ps, 4765 (86.2%) consented to participate in the study. In all, 3313 (69.5%) patients received outpatient treatment and were discharged from the ED following treatment completion, while 1189 (24.7%) were admitted as inpatients from the ED. A total of 238 (5.0%) patients prematurely terminated their treatment on their own volition. In the “post” period, 1643 WIC patients (WIC-Ps) were recorded, of which 1201 (73.1%) consented to participate in the study. Of these, 956 (80.5%) had been referred from the ED registration desk. Overall, 197 (16.4%) patients were referred from the WIC to the ED; of those originally referred onwards from the ED, 790 (82.6%) received definitive care in the WIC, while 166 (17.4%) were referred back to the ED from the WIC.

Table 1 lists the characteristics of all walk-in patients presenting to the ED in the “pre” and “post” periods. Following the opening of the WIC, the average age rose by 2.6 years (42.9 ± 17.9 vs. 45.5 ± 18.7; p < 0.001). The percentage of ED walk-in patients classified as low-urgency (triage level 5) went down from 21.4% to 9.0% (p < 0.001), while the percentage of inpatient admissions rose from 21.9% to 28.3% (p < 0.001) following the opening of the WIC. Premature treatment discontinuation in the ED went down from 6.4% to 3.6% (p < 0.001). The percentage of self-referring patients reduced from 78.6% to 61.2% (p < 0.001). Compared to ED walk-in patients treated as outpatients in the “post” period (eTable 1), WIC patients were younger, with a mean age of 38.8 ± 15.3, and more female, with 55.2% women (compared with 51.8% in the ED). The mean length of stay in the WIC was 90.7 ± 64.1 min (eTable 2).

Table 1

Characteristics of emergency department walk-in patients (4 pm to midnight)

eTable 1

Characteristics of emergency department walk-in patients receiving outpatient care

eTable 2

Characteristics of patients at the urgent care walk-in clinic (4 pm to midnight)

The changes in the population of ED walk-in patients treated as outpatients were further investigated below. We observed a reduction in these patients following the opening of the WIC, whereas the number of patients in the ED admitted as inpatients remained constant (Figure 2). Routine UKE data for the same months in the period 2016–2018 showed no changes in daily case numbers. It was not until the WIC opened in October 2019 that a reduction was seen (eFigure).

Figure 2

Number of walk-in patients at the hospital emergency department (ED) receiving outpatient and inpatient care before and after the introduction of the urgent care walk-in clinic (4 pm to midnight)

eFigure

Trend in monthly case numbers per day compared to previous years

Table 2 shows the reduction in walk-in ED-Ps receiving outpatient care, broken down according to specialties and diagnosis groups. The total number of daily patients fell by 37.3% (95% confidence interval [30.9%; 43.8%]). We saw a decline in seven of 10 specialties in the ED. No specialty experienced an increase in ED-Ps. A reduction in case numbers was observed in all diagnosis groups.

Table 2

Reduction in ED walk-in patients receiving outpatient care according to specialties (4 pm to midnight)

Table 3 shows the mean length of stay of walk-in ED-Ps receiving outpatient care. No change was seen in length of stay between the “pre” and “post” period. However, in the subgroup of self-referring patients, the length of stay fell by 17.6 min ([7.4; 27.8]; p = 0.02) from a mean length of 172 min in the “pre” period. After considering specialties separately, the length of stay among trauma surgery patients went down by 18.3 min; [4.8; 31.9]; p = 0.008. Among dermatology patients, on the other hand, the mean length of stay increased by 35.1 min; [−65.4; −4.9]; p = 0.024. On weekends and public holidays, the length of stay among all walk-in ED-Ps receiving outpatient care went down by 18.8 min ([3.7; 33.8]; p = 0.014).

Table 3

Change in length of stay of ED walk-in patients receiving outpatient treatment (4 pm to midnight)

Discussion

Following the opening of the WIC, the number of walk-in ED-Ps receiving outpatient care fell by 37.3%. The relevance of this reduction in case numbers is evident in the observed shortening of treatment time for self-referring patients that “remained” in the ED. In the overall assessment of ED-Ps that “remained” and WIC-Ps, there was no change in the mean monthly throughput, and hence no evidence of “provider-induced demand” was found. Of the patients referred onwards to the WIC, 82.6% received definitive care there from general practitioners using the available resources (ECG, urine test strips, and point-of-care rapid tests; no laboratory-based diagnostic tests/X-ray diagnosis/ultrasound). In addition, the mean length of stay in the WIC was approximately 50% shorter compared to the ED, suggesting that WICs are a resource-saving treatment option.

The effects of general practitioner cooperatives co-located with emergency departments has already been investigated for a number of European countries. However, there was significant variance in the extent to which these led to a reduction in case numbers (16, 19, 26, 27, 28, 29, 30) (e6, e10, e14). This highlights the need for studies in the country-specific care context.

The 37.3% reduction in the number of walk-in ED-Ps receiving outpatient care recorded in our study confirms estimates for the German health care context that, for medical and economic reasons, statutory health insurance-accredited out-of-hours urgent care would be more appropriate for approximately 30% of outpatients treated in emergency departments (31). Comparable results were reported in Austria following the launch of hospital-integrated general practitioner walk-in clinic (32).

The literature puts the percentage of patients prematurely discontinuing treatment in emergency departments at 2–5% (33, 34). The 6.4% rate of patients discontinuing treatment (“pre” observation period) in our study can be explained by the size of the ED and the study population (walk-in patients), in which the likelihood of leaving during treatment is higher.

Regarding the question of optimizing emergency department processes, particular focus lies on self-referring patients (15, 28, 35, 36), which are reported in the literature to account for 44.7–72.0% of emergency department patients (15, 28, 37) (e6, e15). The comparatively high percentage (78.6%) of self-referring patients (“pre” observation period) in our study can thus be explained by the fact that only patients presenting as outpatients were included. Referral by emergency services was an exclusion criterion, since these patients could not be referred onwards to the WIC. The percentage of self-referring patients went down to 61.2% as a result of the option to refer patients onwards, resulting in a 17-min shorter length of stay for the remaining self-referring patients. In comparable studies, no homogeneous picture could be seen with regard to a shortening of length of stay (23, 26, 38), with some even reporting a prolongation (28, 32). Only for the subgroup of dermatology patients did we record a prolongation of length of stay—despite a reduction in patient numbers. It is possible that as a result of the greatly reduced ED patient numbers, the dermatology physicians on duty concentrated more on the treatment of inpatients, which in turn may have led to longer treatment times in the ED.

Whether specialty-specific length of stay of outpatient ED patients is a suitable measure for process optimization should therefore be investigated, at least for interdisciplinary emergency departments with physicians from numerous specialties. Here, it is also evident that WICs cannot replace continuous process optimization in emergency departments. In order to overcome the problem of a strict separation into “competent” specialties, additional training in “clinical acute and emergency medicine” was, for example, introduced in Germany with the aim of enabling ED physicians to competently treat a multidisciplinary range of emergencies (39).

Trauma surgery, as the specialty with the highest throughput of walk-in patients, showed a significant reduction in length of stay for self-referring patients (18.3 min). In line with this, a recent survey conducted in Germany demonstrated that no inpatient admission took place in 94.5% of self-referring patients with “trauma” as the principal symptom. The authors concluded from this that treatment in the outpatient sector would be possible for these patients and called for alternative outpatient care options (37). A number of international studies have also demonstrated that general practitioner cooperatives co-located with emergency departments result in particular in a reduction in trauma and dermatology cases (20, 32).

Urgent care walk-in clinics in the immediate vicinity of emergency departments, as well as “integrated urgent care walk-in centers” (IWIC) were recommended by the German Advisory Council on “Health” as early on as in 2018 and called for by the German “government commission for needs-based hospital care” in 2023 (40). Our data show that alone the option to refer patients onwards to an adjacent urgent care walk-in center reduces case numbers and shortens waiting times in emergency departments. For > 80% of patients referred onwards, the diagnostic and personnel resources in the WIC were sufficient, at shorter length of stays (172 min in the ED vs. 91 min in the WIC).

Whether closer synergy between EDs and WICs in the form of IWICs with a shared reception desk optimizes the utilization of resources needs to be investigated in future studies.

Strengths and limitations

To the best of our knowledge, this is the first study in the German care context investigating the introduction of an urgent care walk-in clinic at a university hospital emergency department. Due to the comparatively high case numbers and response rate of over 86%, one can assume that the sample is representative with regard to emergency department walk-in patients. Our results enable individual specialties to be quantified and may be helpful in needs planning in an interdisciplinary emergency department from a quality assurance and health-economic perspective.

The study design makes it impossible for us to definitively exclude seasonal factors, such as more frequent injuries due to falls in winter months. However, we saw a clear trend towards a reduction in outpatient ED-Ps in the “post” period, while inpatient admissions remained unchanged (Figure 2). Anonymized routine data from previous years (2016–2018) also revealed no evidence of seasonal factors (eFigure). Organizational adjustments such as boosting staffing levels in the ED were not made during the survey period.

The lack of a control group represents a further limitation. It is possible that these results can be extrapolated to only a limited extent to emergency departments in non-maximum care hospitals outside large cities.

Summary

A general practitioner-led urgent care walk-in clinic co-located with a university hospital emergency department can lead to a reduction in patients receiving outpatient care, shorter treatment times, and fewer treatment discontinuations in the emergency department. Most of the patients referred onwards to the WIC were able to receive definitive care there. Further multicenter studies to quantify the burden-reducing potential of urgent care walk-in centers (including those outside urban/university settings) should follow.

Acknowledgments

The study was financed by own funds of the Institute and Outpatient Clinic for General Practice and the hospital emergency department of the UKE. We would like to thank the Case Management and admissions nurses at the UKE ED and the urgent care walk-in clinic for their assistance in

recruitment. We would also like to thank all participating patients.

Conflict of interest statement
The authors declare that no conflict of interest exists.

Manuscript submitted on 16 December 2022, revised version accepted on 11 May 2023.

Translated from the original German by Christine Rye.

Corresponding author
Dr. med. Jan Hendrik Oltrogge-Abiry
Institut und Poliklinik für Allgemeinmedizin
Universitätsklinikum Hamburg-Eppendorf
Martinistraße 52, 20246 Hamburg, Germany

Cite this as
Bessert B, Oltrogge-Abiry JH, Peters PS, Schmalstieg-Bahr K, Bobardt-Hartshorn JS, Pohontsch NJ, Bracht S, Mayer-Runge U, Scherer M: Synergism of an urgent care walk-in clinic with an emergency department—a pre–post comparative study. Dtsch Arztebl Int 2023; 120: 491–8. DOI: 10.3238/arztebl.m2023.0127

►Supplementary material

eReferences, eTables, eFigure:
www.aerzteblatt-international.de/m2023.0127

References

1. Morley C, Unwin M, Peterson GM, Stankovich J, Kinsman L: Emergency department crowding: a systematic review of causes, consequences and solutions. PLoS One 2018; 13: e0203316

2. George F, Evridiki K: The effect of emergency department crowding on patient outcomes. Health Sci J 2015; 9: 1–6.

3. Hoot NR, Aronsky D: Systematic review of emergency department crowding: causes, effects, and solutions. Ann Emerg Med 2008; 52: 126–36

4. McKenna P, Heslin SM, Viccellio P, Mallon WK, Hernandez C, Morley EJ: Emergency department and hospital crowding: causes, consequences, and cures. Clin Exp Emerg Med 2019; 6: 189–95

5. Naouri D, Ranchon G, Vuagnat A, Schmidt J, El Khoury C, Yordanov Y: Factors associated with inappropriate use of emergency departments: findings from a cross-sectional national study in France. BMJ Qual Saf 2020; 29: 449–64

6. Magnusson C, Ryge H, Scott F, Herlitz J, Axelsson C: Limited need for hospital resources among patients brought to hospital by the emergency medical services. BMC Emerg Med 2021; 21: 156

7. Reinhold AK, Greiner F, Schirrmeister W, Walcher F, Erdmann B: [Even low-acuity patients prefer hospital-based emergency care: a survey of non-urgent patients in an emergency department with unique regional position]. Med Klin Intensivmed Notfmed 2021; 116: 511–21

8. Scherer M, Lühmann D, Kazek A, Hansen H, Schäfer I: Patients attending emergency departments—a cross-sectional study of subjectively perceived treatment urgency and motivation for attending. Dtsch Arztebl Int 2017; 114: 645–52

9. Oltrogge JH, Brandt, B, Mayer-Runge U, et al. Zentrale Notaufnahme einer Universitätsklinik: Vergleich der Patientenallokation durch Pflegekräfte oder Allgemeinmediziner. Z Allg Med 2019; 95: 252–8. https://doi.org/10.3238/zfa.2019.0252-0258 (last accessed on 30 May 2023).

10. Krämer J, Schreyögg J: Substituting emergency services: primary care vs. hospital care. Health Policy 2019; 123: 1053–60

11. Holzinger F, Oslislo S, Möckel M, Schenk L, Pigorsch M, Heintze C: Self-referred walk-in patients in the emergency department—who and why? Consultation determinants in a multicenter study of respiratory patients in Berlin, Germany. BMC Health Serv Res 2020; 20: 848

12. Schmiedhofer M, Möckel M, Slagman A, Frick J, Ruhla S, Searle J: Patient motives behind low-acuity visits to the emergency department in Germany: a qualitative study comparing urban and rural sites. BMJ Open 2016; 6: e013323

13. Searle J, Muller R, Slagman A, et al.: Überfüllung der Notaufnahmen: Gründe und populationsbezogene Einflussfaktoren. Notf Rettungsmedizin 2015; 18: 306–15

14. Bosmans JE, Boeke AJ, Van Randwijck-Jacobze ME, et al.: Addition of a general practitioner to the accident and emergency department: a cost-effective innovation in emergency care. Emerg Med J 2012; 29: 192–6

15. Chmiel C, Wang M, Sidler P, Eichler K, Rosemann T, Senn O: Implementation of a hospital-integrated general practice—a successful way to reduce the burden of inappropriate emergency-department use. Swiss Med Wkly 2016; 146: w14284

16. Crawford J, Cooper S, Cant R, DeSouza R: The impact of walk-in centres and GP co-operatives on emergency department presentations: a systematic review of the literature. Int Emerg Nurs 2017; 34: 36–42

17. Edwards M, Cooper A, Davies F, et al.: Emergency department clinical leads’ experiences of implementing primary care services where GPs work in or alongside emergency departments in the UK: a qualitative study. BMC Emerg Med 2020; 20: 1–10

18. Foster H, Moffat KR, Burns N, Gannon M, Macdonald S, O’donnell CA: What do we know about demand, use and outcomes in primary care out-of-hours services? A systematic scoping review of international literature. BMJ Open 2020; 10: e033481

19. Smits M, Rutten M, Keizer E, Wensing M, Westert G, Giesen P: The development and performance of after-hours primary care in the Netherlands: a narrative review. Ann Intern Med 2017; 166: 737–42

20. Thijssen WAMH, Van Miero E, Willekens M, et al.: Complaints and diagnoses of emergency department patients in the Netherlands: a comparative study of integrated primary and emergency care. PLoS One 2015; 10: 1–11

21. Uthman OA, Walker C, Lahiri S, et al.: General practitioners providing non-urgent care in emergency department: a natural experiment. BMJ Open 2018; 8: 1–7

22. Cooper A, Davies F, Edwards M, et al.: The impact of general practitioners working in or alongside emergency departments: a rapid realist review. BMJ Open 2019; 9: 1–11

23. Ramlakhan S, Mason S, O’Keeffe C, Ramtahal A, Ablard S: Primary care services located with EDs: a review of effectiveness. Emerg Med J 2016; 33: 495–503

24. Van den Heede K, Van de Voorde C: Interventions to reduce emergency department utilisation: a review of reviews. Health Policy 2016; 120: 1337–49

25. Romeo M, Money J, Toloo GS, Lim D: Effectiveness of general practice availability in reducing avoidable utilisation of emergency departments: a rapid review of the literature. 2020. www.doi.org/10.5204/rep.eprints.204642 (last accessed on May 30 2023)

26. Salisbury C, Hollinghurst S, Montgomery A, et al.: The impact of co-located NHS walk-in centres on emergency departments. Emerg Med J 2007; 24: 265–9

27. Van Gils-Van Rooij ESJ, Yzermans CJ, Broekman SM, Meijboom BR, Welling GP, De Bakker DH: Out-of-hours care collaboration between general practitioners and hospital emergency departments in the Netherlands. J Am Board Fam Med 2015; 28: 807–15

28. van Veelen MJ, van den Brand CL, Reijnen R, van der Linden MC: Effects of a general practitioner cooperative co-located with an emergency department on patient throughput. World J Emerg Med 2016; 7: 270–3

29. Arain M, Campbell MJ, Nicholl JP: Impact of a GP-led walk-in centre on NHS emergency departments. Emerg Med J 2015; 32: 295–300

30. Chalder M, Sharp D, Moore L, Salisbury C: Impact of NHS walk-in centres on the workload of other local healthcare providers: time series analysis. BMJ 2003; 326: 532

31. Haas C, Larbig M, Schöpke T, et al.: Gutachten zur ambulanten Notfallversorgung im Krankenhaus. Deutsche Gesellschaft für interdiziplinäre Notfall- und Akutmedizin 2015; 1–82.

32. Fuhrmann V, Herkner H, Laggner AN, Roth D: Short- and intermediate-term effects of a hospital-integrated walk-in clinic on emergency department-visits and case mix. Am J Emerg Med 2021; 46: 410–5

33. Li DR, Brennan JJ, Kreshak AA, Castillo EM, Vilke GM: Patients who leave the emergency department without being seen and their follow-up behavior: a retrospective descriptive analysis. J Emerg Med 2019; 57: 106–13

34. Roby N, Smith H, Hurdelbrink J, et al.: Characteristics and retention of emergency department patients who left without being seen (LWBS). Intern Emerg Med 2022; 17: 551–8

35. Henricson J, Ekelund U, Hartman J, Ziegler B, Kurland L, Björk Wilhelms D: Pathways to the emergency department—a national, cross-sectional study in Sweden. BMC Emerg Med 2022; 22: 58

36. Rutten M, Vrielink F, Smits M, Giesen P: Patient and care characteristics of self-referrals treated by the general practitioner cooperative at emergency-care-access-points in the Netherlands. BMC Fam Pract 2017; 18: 62

37. Gries A, Schrimpf AM, von Dercks N: Hospital emergency departments—utilization and resource deployment in the hospital as a function of the type of referral. Dtsch Arztebl Int 2022; 119: 640–6

38. Thijssen WAMH, Kraaijvanger N, Barten DG, Boerma MLM, Giesen P, Wensing M: Impact of a well-developed primary care system on the length of stay in emergency departments in the Netherlands: a multicenter study. BMC Health Serv Res 2016; 16: 1–8

39. Schultze A, Mayer-Runge U: Notfallversorgung – Reformbedarf aus stationärer Sicht. Inn Med 2022; 63: 914–22

40. Sachverständigenrat zur Begutachtung der Entwicklung im Gesundheitswesen: Bedarfsgerechte Steuerung der Gesundheitsversorgung. Gutachten 2018. www.svr-gesundheit.de/fileadmin/Gutachten/Gutachten_2018/Gutachten_2018.pdf (last accessed on 18 March 2023).

e1. Pines JM, Hilton JA, Weber EJ, et al.: International perspectives on emergency department crowding. Acad Emerg Med 2011; 18: 1358–70

e2. Baibergenova A, Jokovic A, Gushue S: Missed opportunity: patients who leave emergency departments without being seen. Health Policy 2006; 1: 35–42.

e3. Bittencourt RJ, de Medeiros Stevanato A, Bragança CTNM, Gottems LBD, O’Dwyer G: Interventions in overcrowding of emergency departments: an overview of systematic reviews. Rev Saude Publica 2020; 54: 1–13

e4. Sun BC, Hsia RY, Weiss RE, et al.: Effect of emergency department crowding on outcomes of admitted patients. Ann Emerg Med 2013; 61: 605–11.e6

e5. Carret MLV, Fassa ACG, Domingues MR: Inappropriate use of emergency services: a systematic review of prevalence and associated factors. Cad Saúde Pública 2009; 25: 7–28

e6. Van Uden CJT, Winkens RAG, Wesseling G, Fiolet HFBM, Van Schayck OCP, Crebolder HFJM: The impact of a primary care physician cooperative on the caseload of an emergency department: the Maastricht integrated out-of-hours service. J Gen Intern Med 2005; 20: 612–7

e7. Ellbrant J, Åkeson J, Sletten H, Eckner J, Karlsland Åkeson P: Adjacent primary care may reduce less urgent pediatric emergency department visits. J Prim Care Community Health 2020; 11: 2150132720926276

e8. Leigh S, Mehta B, Dummer L, et al.: Management of non-urgent paediatric emergency department attendances by GPs: a retrospective observational study. Br J Gen Pract 2020; 71: e22–e30

e9. Chmiel C, Huber CA, Rosemann T, et al.: Walk-ins seeking treatment at an emergency department or general practitioner out-of-hours service: a cross-sectional comparison. BMC Health Serv Res 2011; 11: 94

e10. Thijssen WAMH, Wijnen-van Houts M, Koetsenruijter J, Giesen P, Wensing M: The impact on emergency department utilization and patient flows after integrating with a general practitioner cooperative: an observational study. Emerg Med Int 2013; 2013: 1–8

e11. Flores-Mateo G, Violan-Fors C, Carrillo-Santisteve P, Peiró S, Argimon JM: Effectiveness of organizational interventions to reduce emergency department utilization: a systematic review. PLoS One 2012; 7: e35903

e12. Scherer M, Boczor S, Weinberg J, et al. Allgemeinmedizin in einer Universitätsklinik — Ergebnisse eines Pilotprojekts. Z Allg Med 2014: 90, 165–17. https://doi.org/10.3238/zfa.2014.0165-0173. (last accessed on 30 May 2023)

e13. WHO: International classification of primary care. Second edition (ICPC-2). www.who.int/standards/classifications/other-classifications/international-classification-of-primary-care (last accessed on 24 May 2023).

e14. van Uden CJT: Does setting up out of hours primary care cooperatives outside a hospital reduce demand for emergency care? Emerg Med J 2004; 21: 722–3

e15. Philips H, Remmen R, Van Royen P, et al.: What’s the effect of the implementation of general practitioner cooperatives on caseload? Prospective intervention study on primary and secondary care. BMC Health Serv Res 2010; 10: 222