Impact of SARS-CoV-2 Subvariants on Postoperative Outcomes in Geriatric Hip Fracture Patients – A Multinational Multicentre Study

Background Hip fractures (HF) are among the most prevalent diagnoses in geriatric traumatology, with persistently high incidence even during the COVID-19 pandemic. Concomitant SARS-CoV-2 infection adds clinical complexity and has been associated with increased mortality and prolonged hospitalisation. This study aimed to assess the impact of SARS-CoV-2 subvariants B.1.1.7 (Alpha), B.1.617.2 (Delta), and B.1.1.529 (Omicron) on postoperative outcomes in patients undergoing surgical treatment for HF. Methods A retrospective multicentre study was conducted using data from the German Registry for Geriatric Trauma (ATR-DGU®) between March 2021 and April 2022 across 119 hospitals. 12707 patients undergoing HF surgery were included and stratified by predominant subvariant periods: Alpha (n = 3714), Delta (n = 5434), and Omicron (n = 3559). Each cohort was further stratified by SARS-CoV-2 status at admission. Results During the Alpha period, in-hospital mortality and length of stay were similar between COVID-19-comorbid (8.3%, 13 days) and SARS-CoV-2-negative patients (5.4%, 15 days). In the Delta and Omicron periods, mortality was significantly higher among COVID-19-comorbid patients (14.3% and 13.9%) compared to SARS-CoV-2-negative patients (5.8%, p = 0.017; 5.7%, p < 0.001), with longer hospitalisations (17 vs. 15 days, p < 0.05). COVID-19-comorbid patients were more frequently institutionalised and exhibited lower levels of pre-fracture mobility compared to SARS-CoV-2-negative patients. Conclusion In contrast to the Alpha period, COVID-19 comorbidity during the Delta and Omicron periods was associated with elevated perioperative mortality and longer hospitalisation, highlighting the clinical relevance of SARS-CoV-2 subvariant characteristics in the management of HF in elderly patients. Trial registration Not applicable. This retrospective study used anonymized data from the German Registry for Geriatric Trauma (ATR-DGU®) and was approved by the ethics committee of the University Münster (reference number: 2022-268-f-S). This study was conducted in accordance with the Declaration of Helsinki.