Role of clinical frailty on long-term mortality of elderly subjects with and without chronic obstructive pulmonary disease

Abstract

Elderly subjects are characterized by a high prevalence of chronic obstructive pulmonary disease (COPD) and frailty. This study examined the predictive role of frailty on long-term mortality in elderly subjects with and without COPD. The study assessed mortality after a 12-year follow-up in 489 subjects with COPD and 799 subjects without COPD, selected in 1992. Frailty was assessed according to the Frailty Staging System scores ranging from 1 to 7. After 12 years' follow-up, mortality was 48.1% in subjects without and 60.7% in subjects with COPD (p<0.001). With increasing frailty, mortality increased from 41.7% to 75.1% (p for trend <0.01) in subjects without and from 54.3% to 97.0% in subjects with COPD (p for trend <0.001). Multivariate analysis showed that both COPD [hazard ratio (HR)=1.34; 95% confidence interval (95% CI)=1.02-1.81; p=0.042] and frailty score (HR=1.69 for each unit of increase; 95% CI=1.42- 2.00; p<0.001) were predictive of long-term mortality. The frailty score also increased the risk of long-term mortality by 34% in the absence of COPD (HR=1.34 for each unit of increase; 95% CI=1.02-1.81; p<0.05) and by 80% in its presence (HR=1.80 for each unit of increase; 95% CI=1.28-2.53; p<0.001). Long-term mortality was higher in elderly subjects with than in those without COPD. The clinical frailty score also significantly predicted mortality in subjects without and, even more, in those with COPD. Thus, clinical frailty may be considered a new prognostic factor to identify COPD subjects at high risk of mortality.