Long-term mortality in frail elderly subjects with osteoarthritis.

Objective: Elderly subjects are characterized by a high prevalence of OA and clinical frailty. This study aimed to examine the predictive role of clinical frailty on long-term mortality in elderly subjects with and without OA.
Methods: Mortality was evaluated after a 12-year follow-up in 698 subjects with and 590 subjects without OA recruited in 1992. Clinical frailty was assessed according to the Frailty Staging System and stratified in tertiles.
Results: After a 12-year follow-up, mortality was 42.2% in subjects without and 55.8% in subjects with OA (P = 0.256). With increasing frailty, mortality increased by 30.5% (P for trend < 0.001) in subjects without and by 45.6% in subjects with OA (P for trend < 0.001). Multivariate analysis showed that frailty [hazard ratio (HR) = 1.49 for each unit of increase, 95% CI 1.32, 1.94, P < 0.001) but not OA (HR = 1.28, 95% CI 0.987, 1.39, P = 0.412) was predictive of long-term mortality. Moreover, when Cox regression analysis was performed, frailty enhanced the risk of long-term mortality for each unit of increase by 32% (HR = 1.32, 95% CI 1.06, 1.65, P = 0.03) in the absence of OA and by 98% in the presence (HR = 1.98, 95% CI 1.63, 2.95, P < 0.01) of OA.
Conclusion: Clinical frailty significantly predicts mortality in subjects without OA and even more in those with OA. Thus clinical frailty may be considered a new prognostic factor to identify subjects with OA at high risk of mortality.