A short length of hospital stay is not associated with risk of readmission among hip fracture patients - a Swedish national register-based cohort study

Hospital length of stay (LoS) after a hip fracture likely mirrors health status; however, a too short hospitalization might increase the risk of readmission. In this national register-based study, we investigated the association between LoS after a hip fracture and the risk of readmissions. 73,551 patients with a first hip fracture between 2012 and 2019 were followed for 4 months after discharge. LoS was categorized by cubic splines and the association with readmissions was analyzed with Cox regression models. The mean LoS was 11 ± 6 days and 25% of the study population had at least one readmission. Compared to the mean LoS of 9-12 days, there was a 18% decreased risk of readmission for LoS of 2-4 days (HR 0.82 [95% CI 0.77-0.87]) and 13% decrease for 5-8 days (HR 0.87 [95% CI 0.83-0.91]), when adjusting for sex, age, walking ability, ASA score, CCI, complications during hospitalization and living arrangements. For longer LoS, risk of readmission increased (13-23 days: HR 1.09 [95% CI 1.05-1.13] and 24 + days: HR 1.19 [95% CI 1.11-1.28]). The results were robust across sex, age, and living arrangements. The most common specific reasons for readmission were trauma/injury, cardiovascular and complications, and the proportions did not differ considerably between short and long LoS-categories. While a long LoS can be explained by the care need of the patient, a short LoS - compared to the average stay - does not increase the risk of readmission regardless of health status and hospital complications in a Swedish setting.