Comparison of lengths of hospital stay after surgery and mortality in elderly hip fracture patients between Japan and the United States – the relationship between the lengths of hospital stay after surgery and mortality

Purpose. To examine whether the length of stay (LOS) after hip fracture surgery was related to mortality after discharge by comparing between hospitals in Japan and the United States (US).Method. This is a retrospective observational study of three hospitals in Japan and two in the Pacific Northwest in the US. The median follow-up day was 276 days after surgery. The participants were 65 years or older who had experienced hip fracture and were admitted to one of the study hospitals for surgery.Results. The median LOS after surgery was 34 days in Japan and 5 days in the US. The survival rate was 89.5% in Japan and 77.2% in the US among patients who could be followed-up. In the Cox regression, every 10 day increase in the LOS after surgery was associated with a 26% reduction in the risk of mortality (Hazard ratio = 0.744, p = 0.014) after adjusting for LOS before surgery, patients' basic characteristics, number of complications and country.Conclusions. Shorter lengths of stay after surgery did not predict better survival across the two countries. Larger longitudinal or randomized studies that determine the effects of LOS after surgery on mortality are necessary.