A team of researchers discovered that weight plays a factor in determining clinical outcomes for patients with interstitial pulmonary fibrosis (IPF), according to a study published in Respiration. 

In clinical settings, the body mass index (BMI) and body weight of patients with IPF are routinely measured. Weight loss is commonly experienced by IPF patients, which increases the risk of early termination of treatment and reductions in the survival rate of that patient. The medical community is currently debating whether to classify weight loss as a prognostic indicator or as a longitudinal marker of IPF. The researchers of this study hence set out to take a closer look at the impact of BMI and body weight on individual clinical outcomes in IPF patients over 1 year. 

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Researchers conducted an ad hoc trial using pooled data from 5 randomized controlled trials involving patients with IPF. Post-hoc analyses of patients at 1 year involved stratifying patients based on their BMI and annualized percentage change in body fat. 

In total, researchers recruited 1604 patients for this study. Having stratified patients according to BMI and annualized percentage change in body fat, the research team measured outcomes in terms of: 

  • Annualized changes from baseline in percent predicted forced vital capacity.
  • Percent predicted carbon monoxide diffusing capacity. 
  • 6-min walk distance. 
  • The St. George’s Respiratory Questionnaire total score.

The results of this study demonstrated that the placebo group with a baseline BMI <25 kg/m2 or annualized weight loss may experience worse outcomes compared to those with a baseline BMI ≥25 kg/m2 or no weight loss. The authors of this study said, “The proportion of placebo-treated patients who experienced a relative decline of ≥10% in %FVC or death up to 1 year post-randomization was highest in patients with a baseline BMI <25 kg/m2.” 

This study demonstrated the impact of suboptimal body mass on the disease course of patients with IPF. The research team concluded, “Future trials should aim to demonstrate whether dedicated management to prevent malnutrition and weight loss can improve clinical outcomes in patients with IPF.”


Jouneau S, Crestani B, Thibault R, et al. Post hoc analysis of clinical outcomes in placebo- and pirfenidone-treated patients with IPF stratified by BMI and weight loss. Respiration. Published online October 5, 2021. doi:10.1159/000518855