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

Abstract

Background: COPD has been found to be associated with frailty. However, longitudinal evidence for associations of COPD with frailty progression is inadequate. Furthermore, recent studies revealed a new phenotype of lung function impairment: preserved ratio impaired spirometry (PRISm) findings. Associations of PRISm findings and their transitions with frailty progression are unclear.

Research question: What are the associations of PRISm findings, transitions of PRISm findings, and COPD with frailty progression?

Study design and methods: To analyze the associations of PRISm findings and COPD with frailty progression, 5,901 patients were included from the English Longitudinal Study of Ageing. Patients were classified into three lung function patterns of normal spirometry (NS) findings, PRISm findings, and COPD. Frailty progression was assessed by repeated measurements of the frailty index (FI) during follow-up. Among these 5,901 patients, 3,765 patients were included to analyze the associations of PRISm findings transitions with frailty progression. PRISm findings transitions were assessed based on the changes of lung function patterns after a 4-year interval. Linear mixed-effect models were used for statistical analyses.

Results: The median follow-up periods were 9.5 years for the analyses of PRISm findings and COPD with frailty progression and 5.8 years for PRISm findings transitions with frailty progression. When compared with participants with NS findings, patients with PRISm findings and COPD demonstrated accelerated FI progression with additional annual increases of 0.301 (95% CI, 0.211-0.392; P < .001) and 0.172 (95% CI, 0.102-0.242; P < .001), respectively. Patients who transitioned from NS findings to PRISm findings also demonstrated accelerated FI progression when compared with those with stable NS findings (β = 0.242; 95% CI, 0.008-0.476; P = .042). However, no accelerated FI progression was found in patients with PRISm findings who transitioned to NS findings (β = 0.119; 95% CI, -0.181 to 0.418; P = .438).

Interpretation: Our findings indicate that PRISm findings and COPD are associated with accelerated frailty progression. Further studies are needed to elucidate the causality of the association of PRISm findings and COPD with frailty.

Keywords: COPD; PRISm; epidemiology; frailty; transition.