Is hospital volume related to quality of hip fracture care? Analysis of 43,538 patients and 68 hospitals from the Dutch Hip Fracture Audit

Purpose: Evidence for a hospital volume–outcome relationship in hip fracture surgery is inconclusive. This study aimed to analyze the association between hospital volume as a continuous parameter and several processes and outcomes of hip fracture care. Methods: Adult patients registered in the nationwide Dutch Hip Fracture Audit (DHFA) between 2018 and 2020 were included. The association between annual hospital volume and turnaround times (time on the emergency ward, surgery < 48 h and length of stay), orthogeriatric co-treatment and case-mix adjusted in-hospital and 30 days mortality was evaluated with generalized linear mixed models with random effects for hospital and treatment year. We used a fifth-degree polynomial to allow for nonlinear effects of hospital volume. P-values were adjusted for multiple comparisons using the Bonferoni method. Results: In total, 43,258 patients from 68 hospitals were included. The median annual hospital volume was 202 patients [range 1–546]. Baseline characteristics did not differ with hospital volume. Provision of orthogeriatric co-treatment improved with higher volumes but decreased at > 367 patients per year (p < 0.01). Hospital volume was not significantly associated with mortality outcomes. No evident clinical relation between hospital volume and turnaround times was found. Conclusion: This is the first study analyzing the effect of hospital volume on hip fracture care, treating volume as a continuous parameter. Mortality and turnaround times showed no clinically relevant association with hospital volume. The provision of orthogeriatric co-treatment, however, increased with increasing volumes up to 367 patients per year, but decreased above this threshold. Future research on the effect of volume on complications and functional outcomes is indicated.