Patient Factors Associated with 10-Year Survival After Arthroplasty for Hip Fracture: A Population-Based Study in Ontario, Canada.

Abstract

BACKGROUND The aim of this study was to describe long-term (10-year) patient survival after arthroplasty for hip fracture and to determine what patient factors are associated with that outcome. METHODS We performed a retrospective cohort analysis of patients ≥60 years old who underwent either hemiarthroplasty or total hip arthroplasty for femoral neck fracture between 2002 and 2009. We used routinely collected, validated health-care databases linked through ICES (formerly known as the Institute for Clinical Evaluative Sciences). We estimated the association between baseline variables and survival 10 years post-fracture using Poisson regression. Restricted cubic spline functions modeled the probability of 10-year survival by age and tested whether there was an inflection point after which the probability of 10-year survival decreased more rapidly. We estimated 10-year survival probabilities for different patient groups. RESULTS There were 19,659 patients in the final cohort. Eighteen percent (3,564) of the patients were alive at 10 years postoperatively. Factors associated with a higher likelihood of 10-year survival included younger age, female sex (risk ratio [RR] = 1.56, 95% confidence interval [CI] = 1.46 to 1.68), lower American Society of Anesthesiologists (ASA) class (ASA I or II versus IV or V: RR = 1.96, 95% CI = 1.76 to 2.19), independent living status (RR = 2.68, 95% CI = 2.23 to 3.22), and fewer specific comorbidities. A threshold age of 73 years was the inflection point after which the probability of 10-year survival decreased more rapidly in females. Estimated 10-year survival probabilities ranged from 79.0% (95% CI = 75.5% to 82.5%) to 0.8% (95% CI = 0.6% to 1.0%). CONCLUSIONS Approximately 1 in 6 patients live at least 10 years following a hip fracture. This study identifies baseline characteristics that predict survival greater than 10 years, including an age of <75 years, an ASA class of I or II, and independent living status prior to the hip fracture. Results can inform discussions around treatment choices, anticipated outcomes, and the natural history of hip fractures. LEVEL OF EVIDENCE Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.