Hospital Length of Stay After Hip Fracture and It's Association With 4-Month Mortality-Exploring the Role of Patient Characteristics

BACKGROUND: Hospital length of stay (LoS) is believed to be associated with higher mortality in hip fracture patients; however, previous research has shown conflicting results. We aimed to explore the association between LoS and 4-month mortality in different groups of hip fracture patients. METHODS: The study population in this Swedish register-based cohort study was 47 811 patients 65 years or older with a first hip fracture during 2012-2016, followed up for 4 months after discharge. LoS was categorized by cubic splines, and the association between LoS and mortality was analyzed with Cox regression models, adjusted for sociodemographic- and health-related factors. RESULTS: Mean LoS was 11.2 ± 5.9 days and 12.3% of the patients died within 4 months. Both a shorter and a longer LoS, compared to the reference 9-12 days, were associated with higher mortality (hazard ratio [95% confidence interval]): 2-4 days 2.15 (1.98-2.34), 5-8 days 1.58 (1.47-1.69), and 24+ days 1.29 (1.13-1.46). However, in fully adjusted models, only the association with a long LoS remained: 13-23 days 1.08 (1.00-1.17) and 24+ days 1.42 (1.25-1.61). Stratifying by living arrangement revealed that the increased risk for a short LoS was driven by the group living in care homes. For patients living at home, a short LoS was associated with lower risk: 0.65 (0.47-0.91) and 0.85 (0.74-0.98) for 2-4 and 5-8 days, respectively. CONCLUSIONS: A long LoS after a hip fracture is associated with increased 4-month mortality risk even after considering patient characteristics. The association between mortality and a short LoS, however, is explained by individuals coming from care homes (with higher mortality risk), being discharged early.