Peak expiratory flow rate (PEFR) is a cheap and simple tool for assessing airway patency and respiratory muscle strength. So far, the impact of PEFR, particularly its longitudinal changes, on the prevalence and incidence of sarcopenia remains underexplored. Therefore, we conducted a cross-sectional and longitudinal study to address this gap.

We analyzed data from the China Health and Retirement Longitudinal Study (CHARLS). A total of 5,280 older adults were selected as a cohort in 2011, of whom 3,686 were confirmed sarcopenia-free at baseline and followed through 2015. Longitudinal changes in PEFR were measured in 2011 and 2013, with complete paired data available for 2,904 subjects. Sarcopenia was diagnosed according to the 2019 Asian Working Group for Sarcopenia (AWGS). Multivariable logistic regression and discrete-time proportional hazards models were used to assess associations between baseline PEFR, 2-year PEFR changes, and sarcopenia risk, adjusting for potential confounders.

A 1-standard deviation (SD) decrease in baseline PEFR was associated with 56% higher odds of prevalent sarcopenia (OR = 1.56, 95% CI = 1.38−1.75), and PEFR (% predicted) <80% with 93% higher odds (OR = 1.93, 95% CI = 1.49–2.50). Over the 4-year follow-up, these reductions were linked to increased risk of incident sarcopenia (HR = 1.26, 95% CI = 1.13−1.40, and HR = 1.47, 95% CI = 1.17−1.84, respectively). A decline from PEFR (% predicted) ≥80% to <80% was associated with 120% higher odds (OR = 2.20, 95% CI = 1.31−3.71), while improvement from <80% to ≥80% was linked to 30% lower odds (OR = 0.70, 95% CI = 0.50−0.96).

Lower baseline PEFR and its longitudinal decline were associated with increased risk of sarcopenia, while upward changes were linked to lower risk. These findings suggest that PEFR may serve as a practical early marker for identifying older adults at elevated risk of sarcopenia.