Reassessment of risk profiles through weight and BMI changes in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease in which weight loss and low BMI have emerged as adverse prognostic indicators. However, longitudinal data on early weight change-particularly in patients receiving antifibrotic therapy-remain limited. This study examined the relationship between first-year weight change and clinical outcomes in a multicenter IPF cohort from Türkiye.

This retrospective study analyzed 428 patients diagnosed with IPF between 2019 and 2024 across 12 centers. Weight at diagnosis and one year, clinical characteristics, antifibrotic treatment, pulmonary function tests, 6MWD, and survival outcomes were evaluated. Annual weight change was categorized as no loss, <5% loss, or ≥5% loss; significant weight loss was defined as ≥5%.

Among 428 patients (mean age 68.3 ± 8.0 years; 82% male), 78.5% experienced significant weight loss during follow-up. At the end of the first year, baseline BMI and the prevalence of diabetes mellitus decreased progressively with increasing weight loss, with the lowest values observed in patients with ≥5% weight loss (p = 0.018 and p = 0.023, respectively). In parallel, greater weight loss at the end of the first year was associated with worse pulmonary function, reflected by declining FVC (L and % predicted) and DLCO (% predicted), while rates of dietitian evaluation increased markedly, reaching the highest level in the ≥5% weight loss group (all p ≤ 0.036). During follow-up, patients with ≥5% weight loss lost an average of 6.20 kg, while those without loss gained 0.22 kg (p < 0.001). Greater annual FVC decline occurred in both weight-loss groups (p = 0.018 and p = 0.005), whereas DLco decline was similar across groups. Antifibrotic use-especially nintedanib-was more frequent among those with ≥5% loss (p = 0.010). Weight loss was not associated with mortality or hospitalization, but correlated with greater functional deterioration. Age and baseline BMI independently predicted weight change.

Early weight loss is common in IPF and is associated with accelerated functional decline, independent of antifibrotic therapy. Routine weight monitoring may provide additional prognostic value and supports incorporating body composition into IPF risk stratification.