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.