How body composition changes when taking lung fibrosis medications

This study is testing whether two simple, quick measurement methods—bioimpedance analysis (a machine that sends a gentle electrical signal through your body) and ultrasound of your thigh muscle—can detect changes in how much muscle and fat you have. Patients with idiopathic pulmonary fibrosis or progressive pulmonary fibrosis who are starting anti-fibrotic medications like nintedanib or pirfenidone often experience stomach problems (nausea, loss of appetite, and diarrhea) that can affect their body composition in ways that regular weight or BMI measurements can't catch.

The medications used to treat pulmonary fibrosis commonly cause side effects that affect digestion and appetite, which may cause patients to lose muscle or gain fat without any change in overall weight. This study wants to see if these new measurement methods can reliably detect these changes so doctors can better monitor and support patients taking this treatment.