Association between preserved ratio impaired spirometry and frailty risk among US adults: a cross-sectional study

Objectives This study aimed to elucidate the relationship between preserved ratio impaired spirometry (PRISm) and risk of frailty and to identify potential risk factors. Design Cross-sectional study. Setting The National Health and Nutrition Examination Survey 2007–2012. Participants A total of 6769 participants aged 40–85 years were included in this study: 1042 with PRISm, 702 with chronic obstructive pulmonary disease (COPD) and 5025 with non-PRISm/COPD. Exposure and outcome measures Frailty was evaluated using a frailty index, categorising participants into non-frail (score <0.21) and frail (score ≥0.21). Weighted logistic regression with multivariable adjustment was conducted to investigate the relationship between PRISm and frailty as well as to identify risk factors. Results The prevalence of frailty significantly differed among the three cohorts (p<0.0001), with PRISm patients and COPD patients exhibiting higher rates (32.4% and 30.4%, respectively) than the non-PRISm/COPD group (13.6%). In the unadjusted models, PRISm patients exhibited a threefold increased risk of frailty (OR 3.03, 95% CI 2.47 to 3.72), similar to COPD patients (OR 2.77, 95% CI 2.19 to 3.50). Adjusted models confirmed a comparable risk of frailty in PRISm patients (OR 1.42, 95% CI 1.09 to 1.83) and COPD patients (OR 1.65, 95% CI 1.17 to 2.32). The findings remained robust across sensitivity and subgroup analyses. Risk factors for frailty among PRISm patients included female sex, non-Hispanic black and other races, higher body mass index, smoking history, diabetes and cardiovascular disease. Conclusion PRISm has a similar prevalence and risk of frailty as COPD, both of which are greater than those of non-PRISm/COPD. This highlights the importance of frailty in patients with PRISm.