Preserved Ratio Impaired Spirometry and COPD Accelerate Frailty Progression: Evidence From a Prospective Cohort Study

Abstract

Chronic obstructive pulmonary disease (COPD) was found to associate with frailty. However, there is inadequate longitudinal evidence for associations of COPD with frailty progression. Furthermore, recent studies revealed a new phenotype of lung function impairment: preserved ratio impaired spirometry (PRISm). Associations of PRISm and its transitions with frailty progression are unclear. What are the associations of PRISm, transitions of PRISm, and COPD with frailty progression? To analyze the associations of PRISm and COPD with frailty progression, 5,901 subjects were included from the English Longitudinal Study of Ageing. Subjects were classified into three lung function patterns of normal spirometry, PRISm, and COPD. Frailty progression was assessed by repeated measurements of the frailty index (FI) during follow-up. Among these 5,901 subjects, 3,765 subjects were included to analyze the associations of PRISm transitions with frailty progression. PRISm transitions were assessed based on the changes of lung function patterns after a four-year interval. Linear mixed-effect models were used for statistical analyses. The median follow-up periods were 9.5 years for the analyses of PRISm and COPD with frailty progression and 5.8 years for PRISm transitions with frailty progression. When compared with normal spirometry, subjects with PRISm and COPD presented accelerated FI progression with additional annual increases of 0.301(95%CI: 0.211 to 0.392, P<0.001) and 0.172(95%CI: 0.102 to 0.242, P<0.001), respectively. Subjects who transitioned from normal spirometry to PRISm also presented accelerated FI progression when compared with stable normal spirometry (β=0.242, 95%CI: 0.008 to 0.476, P=0.042). However, no accelerated FI progression was found in PRISm subjects who transitioned to normal spirometry (β=0.119, 95%CI: -0.181 to 0.418, P=0.438). Our findings indicate that PRISm and COPD are associated with accelerated frailty progression. Further studies are needed to elucidate the causality of PRISm and COPD with frailty.