Body mass index is associated with clinical outcomes in idiopathic pulmonary fibrosis

TL;DR

This study finds that body mass index affects mortality and hospitalization rates in patients with idiopathic pulmonary fibrosis.

Contribution

The study provides new evidence on the clinical impact of BMI in idiopathic pulmonary fibrosis patients using national health claims data.

Findings

Overweight patients had a lower risk of mortality compared to normal weight patients.

Underweight patients had a higher risk of mortality and hospitalization.

BMI showed a non-linear relationship with mortality outcomes in IPF patients.

Abstract

Association between body mass index (BMI) and prognosis in patients with idiopathic pulmonary fibrosis (IPF) remains uncertain. We investigated the association between BMI and clinical outcomes in patients with IPF using national health claims data. The study included 11,826 patients with IPF and rare incurable disease exemption codes (mean age: 68.9 years, male: 73.8%) and available BMI data who visited medical institutions between January 2002 and December 2018. Multivariable Cox proportional hazard models were used to evaluate the association of BMI with all-cause mortality and hospitalization. Based on BMI, 3.1%, 32.8%, 27.8%, and 36.4% were classified as underweight, normal, overweight, and obese, respectively. Multivariable analysis showed independent associations of overweight (hazard ratio [HR] 0.856, 95% confidence interval [CI] 0.801–0.916) and underweight (HR 1.538, 95% CI 1.347–1.757) with mortality in patients with IPF. Similarly, overweight (HR 0.887, 95% CI 0.834–0.943) and underweight (HR 1.265, 95% CI 1.104–1.449) were also associated with hospitalization in patients with IPF in the multivariable analysis. Spline HR curve analysis adjusted for all covariates revealed a non-linear relationship between BMI and mortality in patients with IPF. Our data suggest that BMI is associated with clinical outcomes in patients with IPF.

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