Post hoc Analysis of Clinical Outcomes in Placebo- and Pirfenidone-Treated Patients with IPF Stratified by BMI and Weight Loss

Background: Weight loss is frequently reported in patients with idiopathic pulmonary fibrosis (IPF) and may be associated with worse outcomes in these patients.

Objective: The aim of this study was to investigate the relationships between body mass index (BMI) and weight loss, and outcomes over 1 year in patients with IPF.

Methods: Data were included from placebo patients enrolled in ASCEND (NCT01366209) and CAPACITY (NCT00287716 and NCT00287729), and all patients in INSPIRE (NCT00075998) and RIFF Cohort A (NCT01872689). An additional analysis included data from pirfenidone-treated patients. Outcomes (annualized change in percent predicted forced vital capacity [%FVC], percent predicted carbon monoxide diffusing capacity, 6-min walk distance, St. George's Respiratory Questionnaire total score, hospitalization, mortality, and serious adverse events) were analyzed by baseline BMI (<25 kg/m2, 25 kg/m2-<30 kg/m2, or ≥30 kg/m2) and annualized percent change in body weight (no loss, >0-<5% loss, or ≥5% loss).

Results: Placebo-treated patients with a baseline BMI <25 kg/m2 or annualized weight loss may experience worse outcomes versus those with a baseline BMI ≥25 kg/m2 or no weight loss. 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. Pirfenidone-treated patients with an annualized weight loss ≥5% may also experience worse outcomes versus those with no weight loss.

Conclusions: Patients with a baseline BMI <25 kg/m2 or annualized weight loss of >0-<5% or ≥5% may experience worse outcomes over 1 year versus those with a baseline BMI ≥25 kg/m2 or no weight loss.