# Association between body mass index and prognosis in interstitial lung disease: systematic review and meta-analysis

## TL;DR

This study finds that higher body mass index is linked to lower mortality and better lung function in patients with interstitial lung disease.

## Contribution

The study provides a systematic review and meta-analysis confirming a protective effect of higher BMI in interstitial lung disease prognosis.

## Key findings

- Obesity is associated with lower mortality in interstitial lung disease patients.
- Higher BMI correlates with slower decline in lung function and better baseline lung function.
- Higher BMI is inversely associated with mortality risk in interstitial lung disease.

## Abstract

Interstitial lung disease (ILD) is a heterogeneous group of disorders characterized by lung inflammation and fibrosis. Given inconsistent evidence on the prognostic role of body mass index (BMI), we conducted a systematic review and meta-analysis to investigate the association between BMI and clinical outcomes in ILD. PubMed/MEDLINE, Embase, and the Cochrane Library were searched through May 2024 to investigate the impact of BMI on mortality (24 studies), hospitalization (four studies), baseline lung function (10 studies), and forced vital capacity (FVC) changes (five studies) in ILD patients. BMI was analyzed categorically (obese vs. non-obese) and continuously. Heterogeneity was assessed by subgroup analysis and sensitivity analysis. Twenty-five articles including 23,741 patients were analyzed; more than half were cohort studies. Obesity was associated with lower mortality (RR = 0.91, 95% CI = 0.87–0.94, I2 = 0%) and higher BMI was inversely associated with mortality (HR = 0.94, 95% CI = 0.92–0.96, I2 = 56%). Obese patients showed lower baseline FVC (MD = -1.61, 95% CI = -3.10 to -0.12, I2 = 64%), higher baseline diffusing capacity for carbon monoxide (MD = 1.85, 95% CI = 0.84–2.85, I2 = 42%) and a slower FVC decline (MD = 1.26, 95% CI = 0.85–1.68, I2 = 0%). Overall, higher BMI may be associated with lower mortality and better lung function in patients with ILD.

https://www.crd.york.ac.uk/prospero/, identifier CRD42023461730.