Obesity-Related Indices and Hospitalized Acute Exacerbation in COPD Patients: Sex-Stratified Associations from a Retrospective Cross-Sectional Study

Abstract

Background Obesity is a major risk factor for adverse prognosis in patients with chronic obstructive pulmonary disease (COPD); however, the associations of obesity-related indices with acute exacerbation of COPD (AECOPD) and the potential sex differences therein remain unclear. This study aimed to investigate the sex-specific associations between multiple obesity-related indices and the prevalence of hospitalized AECOPD. Methods This retrospective cross-sectional study included 968 COPD patients (529 males, 439 females) admitted to a comprehensive hospital in Western China. Eight indices were examined: body mass index (BMI), waist-to-hip ratio (WHR), body roundness index (BRI), conicity index (CI), body adiposity index (BAI), abdominal volume index (AVI), lipid accumulation product (LAP) and visceral adiposity index (VAI). The outcome was AECOPD requiring hospitalization; patients hospitalized for non-exacerbation reasons formed the comparison group. Logistic regression (crude, minimally adjusted, fully adjusted) assessed the associations. Additionally, sex-by-index interactions were tested in the pooled sample with Holm adjustment for multiple comparisons. Receiver operating characteristic (ROC) analyses were performed to evaluate the discriminative ability of the indices, including comparisons of the area under the curve (AUC) between indices (DeLong tests with Holm adjustment). Results The overall prevalence of hospitalized AECOPD was 27.3%, with no significant difference between males and females (P=0.74). All eight indices were positively associated with hospitalized AECOPD in both sexes (all P<0.01). In females, AVI had the highest AUC (0.764), followed by CI (0.747) and BRI (0.730), all significantly higher than BMI after Holm correction. In males, VAI had the numerically highest AUC (0.705), followed by BRI (0.687) and LAP (0.676), but only BRI was significantly higher than BMI (P=0.022). Only the sex-by-AVI interaction remained significant after correction (P=0.011). Conclusion All eight indices were positively associated with hospitalized AECOPD, with sex-specific discriminative ability. In females, AVI had the highest AUC and outperformed all other indices after correction, whereas in males VAI had the numerically highest AUC, but most differences were not statistically significant. These findings suggest that refined anthropometric measures reflecting body fat distribution warrant further investigation as potential markers of AECOPD.