Do patients referred to emergency departments after being assessed in primary care differ from other ED patients? Retrospective analysis of a random sample from two German metropolitan EDs

BACKGROUND: To assess differences between patients referred to emergency departments by a primary care physician (PCP) and those presenting directly and the impact of referral on the likelihood of admission. DESIGN OF STUDY: Retrospective cohort study. SETTING: EDs of two nonacademic general hospitals in a German metropolitan region. PARTICIPANTS: Random sample of 1500 patients out of 80,845 presentations during the year 2019. RESULTS: Age was 55.8 ± 22.9 years, and 51.4% was female. A total of 34.7% presented by emergency medical services (EMS), and 47.7% were walk-ins. One-hundred seventy-four (11.9%) patients were referred by PCPs. Referrals were older (62.4 ± 20.1 vs 55.0 ± 23.1 years, p < .001) and had a higher Charlson Comorbidity Index (CCI) (3 (1–5) vs 2 (0–4); p < .001). Referrals received more ultrasound examinations independently from their admission status (27.6% vs 15.7%; p < .001) and more CT and laboratory investigations. There were no differences in sex, Manchester Triage System (MTS) category, or pain-scale values. Referrals presented by EMS less often (9.2% vs 38.5%; p < .001). Admission rates were 62.6% in referrals and 37.1% in non-referrals (p < .001). Referral (OR 3.976 95% CI: 2.595–6.091), parenteral medication in ED (OR 2.674 (1.976–3.619)), higher MTS category (1.725 (1.421–2.093)), transport by EMS (1.623 (1.212–2.172)), abnormal vital parameters (1.367 (0.953–1.960)), higher CCI (1.268 (1.196–1.344)), and trauma (1.268 (1.196–1.344)) were positively associated with admission in multivariable analysis, whereas ultrasound in ED (0.450 (0.308–0.658)) and being a nursing home resident (0.444 (0.270–0.728)) were negatively associated. CONCLUSION: Referred patients were more often admitted. They received more laboratory investigations, ultrasound examinations, and computed tomographies. Difficult decisions regarding the necessity of admission requiring typical resources of EDs may be a reason for PCP referrals. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12245-023-00542-9.