Relationships between frailty, changes in frailty, and incidences of chronic lung disease: findings from six population-based cohort studies

Frailty is a dynamic process that may influence chronic lung disease (CLD). The aims of this study were to explore the associations between frailty, its changes, and the risk of CLD across six longitudinal studies. Data from six large-scale prospective cohorts in the US, England, Europe, China, Korea, and Mexico were used in this study. Univariate and multivariate Cox proportional hazards models were developed to assess the relationships between frailty, changes in frailty, and CLD risk. Meta-analyses were performed to investigate the synthesized effect sizes across all cohorts. Of the total 90,709 participants included in this study, 5921 developed CLD during a median follow-up time of 6.1–9.9 years from baseline to the latest surveys. Frailty at baseline was significantly associated with an increased CLD risk. Compared with participants who remained robust status, those who changed from robust to pre-frail or frail status showed an elevated CLD risk (hazard ratios [HR] range: 1.81 [95% confidence interval [CI] 1.38–2.37] to 2.11 [95% CI 1.00–4.46]). In contrast, participants who recovered from frail to robust or pre-frail status demonstrated a reduced CLD risk (HR range: 0.10 [95% CI 0.03–0.40] to 0.69 [95% CI 0.54–0.89]) compared with stable frail participants. Pooled adjusted HRs showed that frailty and its changes were markedly associated with CLD. In general, frailty was associated with incident CLD; dynamic changes in frailty status were associated with different risks of CLD, i.e., frailty progression increased CLD risk, while frailty reversal reduced the risk. This study suggests that timely interventions for frailty may mitigate CLD risk.