The joint association between inflammation and centripedal obesity with mortality risk in patients with preserved ratio impaired spirometry

The relationship between systemic inflammation and centripedal obesity in predicting mortality risk among patients with Preserved Ratio Impaired Spirometry (PRISm) has garnered increasing interest. This study aims to elucidate the joint effects of these factors on mortality risk in this patient population. This study included data from the National Health and Nutrition Examination Survey (NHANES) of U.S. adults collected from 2007-2012, calculating both the systemic inflammation response index (SIRI) and the weight-adjusted waist index (WWI). Lung function parameters were used to define PRISm cases. Generalized linear models and logistic regression were used to assess the individual and combined effects of SIRI and WWI, and further explored the mediating role of the SIRI. A total of 1454 PRISm patients were included in this study, with a median follow-up period of 9.5 years, during which 10.9% died from all causes and 3.6% from cardiovascular diseases. The restricted cubic spline curves for SIRI and WWI showed J-shaped associations with mortality. Participants with both high WWI (≥11.18) and high Ln SIRI (≥0.13) had significantly higher all-cause and cardiovascular mortality compared with those with low WWI and low SIRI. In the discordant groups, high WWI with low SIRI was associated with increased all-cause mortality (HR = 1.795, 1.050-3.064), while low WWI with high SIRI was linked to higher cardiovascular mortality (HR = 4.844, 1.505-15.591). This effect was more pronounced in the smoking subgroup. Additionally, SIRI mediated 9% of the association between WWI and all-cause mortality, and 12.94% of the association with cardiovascular mortality. Our study provides evidence for the relationship between SIRI and WWI with mortality in PRISm patients. The joint association of these factors provide potential insights for additional information for prognostic prediction and may contribute to identifying risk stratification in PRISm.