Trends in obesity prevalence among total hip arthroplasty patients and the effect on surgical outcomes, 2008–2016

Abstract

IntroductionThe prevalence of obesity continues to rise in parallel with demand for total hip arthroplasty (THA). This study aims to report obesity trends in primary THA and its effects on procedure outcomes in the United States, stratifying based on Body Mass Index (BMI). MethodsPrimary THA procedures were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2008–2016). Patient demographic (including BMI), primary outcomes (death; serious morbidity), and secondary outcome variables were analyzed. Using BMI comparison groups (Obese: BMI > 30 [O]; Morbidly Obese: BMI > 40 [MO]) for case populations, univariate, propensity score-matched, and multivariate logistic regression analyses were performed. ResultsThe prevalence of obesity increased among primary THA (2008: 546/1200 [45.5%], 2016: 16,078/34,137 [47.1%]) cases. Data on 135,013 primary THA cases were analyzed. Propensity score-matched analyses demonstrated that both serious morbidity (O: OR = 0.73, p < 0.001; MO: OR = 0.84, p = 0.001) and frequency of discharges home (O: OR = 0.90, p < 0.001; MO: OR = 0.71, p < 0.001) were significantly reduced. Instead, long operative times (O: OR = 1.30, p < 0.001; MO: OR = 1.53, p < 0.001), readmission (O: OR = 1.27, p < 0.001; MO: OR = 1.49, p < 0.001), and reoperation (O: OR = 1.44, p < 0.001, MO: OR = 1.96, p < 0.001) were all significantly increased in both obese and morbidly obese cases. Death (OR = 0.29; p = 0.016) was decreased in the MO cohort, while length of stay (OR = 1.19, p = 0.004) was increased in the MO cohort. ConclusionBoth obese and morbidly obese primary THA patient populations were associated with variably increased complication risks; morbidly obese patients had higher complication rates relative to obese patients. Orthopaedic surgeons should continue to consider obesity as a risk factor for THA complications. However, given similar functional outcomes and satisfaction levels as non-obese patients, denying patients THA surgery based on BMI alone may merit reconsideration.