Long-Term Mortality of Patients With Osteoarthritis After Joint Replacement: Prognostic Value of Preoperative and Postoperative Pain and Function

Objective: To investigate whether osteoarthritis (OA)-specific assessment values (i.e., Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]) and generic pain and function (visual analog scale, Hanover Functionality Status Questionnaire) measured before and 12 months after arthroplasty are associated with the risk of long-term mortality in a cohort of patients with advanced OA of the hip or knee. Methods: The Ulm Osteoarthritis Study was a prospective cohort study of OA patients with unilateral total hip or knee replacement between January 1995 and December 1996. Correlation coefficients were calculated to describe the agreement between the different assessments. Mortality was assessed during the follow-up period (last update July 2019). Cox proportional regression models were used to estimate hazard ratios (HRs) for mortality after adjusting for covariates. Results: Arthroplasty was accompanied by a clear reduction in pain and improved function throughout all assessments in the 706 included patients. The results of the adjusted Cox models showed no relationship between baseline and follow-up joint-specific WOMAC assessments and long-term mortality. However, an independent increased risk of mortality was found with generic function assessments. In the final adjusted model, the HR for the 12-month follow-up value was 1.79 (95% confidence interval 1.24–2.60) in the group with clinically relevant impairment versus the reference group. Conclusion: Poor function based on the generic assessment was associated with increased long-term mortality, suggesting that functional impairments in daily life activities may be more important for long-term survival than OA-specific impairments in this patient group.