Association between frailty transitions and chronic lung disease incidence: findings from four national cohort studies

The association between changes in frailty status and the prevalence of chronic lung diseases (CLD) is critical. This study aims to explore the relationship between variations in frailty status and incidence of CLD. This study utilized data from four national prospective cohorts: China Health and Retirement Longitudinal Study (CHARLS), English Longitudinal Study of Ageing (ELSA), Health and Retirement Study (HRS) and Survey of Health, Ageing and Retirement in Europe (SHARE). Changes in frailty status were assessed using the Rockwood Frailty Index. CLD was defined as self-reported physician-diagnosed chronic lung diseases, including chronic bronchitis, emphysema, cor pulmonale. Cox proportional hazards model was employed to examine the relationship between changes in frailty status and the incidence of CLD. The analysis included 38,122 participants from four cohorts. Participants who progressed to prefrail or frail status had a significantly higher risk of developing CLD compared to those who remained robust (CHARLS, HR: 1.85, 95% CI: 1.47–2.32; HRS, HR: 1.84, 95% CI: 1.34–2.51; ELSA, HR: 1.58, 95% CI: 1.08–2.31; SHARE, HR: 1.70, 95% CI: 1.40–2.07). Conversely, individuals who transitioned to robust status demonstrated a lower risk of incident CLD compared to those who remained in prefrail or frail status (CHARLS, HR: 0.59, 95% CI: 0.48–0.73; HRS, HR: 0.71, 95% CI: 0.49–1.01; ELSA, HR: 0.57, 95% CI: 0.36–0.89; SHARE, HR: 0.71, 95% CI: 0.55–0.92). Different changes in frailty status are associated with varying risks of developing CLD. Progression of frailty status is associated with the increasing risk of CLD, whereas recovery from frailty is associated with the decreased risk of CLD. The findings suggest that changes in frailty status can serve as important indicators for predicting the risk of developing CLD, where frailty progression elevates risk while recovery from frailty mitigates it. Question What are the associations of changes in frailty status with risks of incident chronic lung disease (CLD)? Finding Progression from robust to pre-frail or frail status increased risks of incident CLD, while recovery from pre-frail or frail statust to robust status, and decreased risks of incident CLD. Conclusions Changes in frailty status affect incident CLD risk. Abbreviations:CHARLS, China Health and Retirement Longitudinal Study ; HRS, Health and Retirement Study; ELSA, English Longitudinal Study of Ageing.; SHARE, Survey of Health, Ageing and Retirement in Europe