Association between waist-to-height ratio and cardiovascular events in patients with chronic obstructive pulmonary disease: the mediating effect of prognostic nutritional index

To explore the relationship between waist-to-height ratio (WHtR) and the risk of cardiovascular disease (CVD) in patients with chronic obstructive pulmonary disease (COPD), and to analyze the mediating role of prognostic nutritional index (PNI) in this association. This study was based on the National Health and Nutrition Examination Survey (NHANES) database from 2007 to 2018, including a total of 1,013 eligible COPD patients. Multivariate logistic regression analysis was used to evaluate the association between WHtR and CVD, and restricted cubic spline regression was applied to explore their non-linear relationship. Meanwhile, mediating effect analysis (Hayes Process Macro Model 4) was conducted to investigate the mediating role of PNI between WHtR and CVD. WHtR was an independent risk factor for cardiovascular disease in COPD patients (OR = 5.76, P = 0.028). Restricted cubic spline results showed a positive correlation between WHtR and CVD risk without a significant non-linear relationship (P for non-linearity = 0.247). Mediation analysis revealed that PNI played a partial mediating role between WHtR and CVD (the indirect effect accounted for 7.98% of the total effect, P < 0.001), suggesting that WHtR may increase CVD risk by affecting the body’s nutritional status. WHtR is an important predictor of CVD in COPD patients, and PNI exerts a partial mediating effect between them. Controlling WHtR and improving nutritional status may help reduce the risk of cardiovascular disease in COPD patients.