A Pilot Study to Assess Body Mass Composition Measurement Using BIA and Muscle Ultrasound in IPF and PPF Patients on Anti-fibrotic Medications

This study will be looking at the measurement of body mass composition using bioimpedance analysis (BIA) and quadriceps muscle ultrasound in patients with fibrotic lung disease who are on anti-fibrotic drugs. These anti-fibrotic drugs (nintedanib and pirfenidone) commonly cause gastrointestinal side effects such nausea, loss of appetite and diarrhoea. As a result of these side effects some patients may have a change in the amount of body fat and muscle. This change is not able to be identified using weight or body mass index (BMI). BIA machines are a quick and easy method of looking at body mass composition and require patients to have electrodes attached to their body for approximately 6 seconds. BIA machines are already in routine care for patients with other types of lung conditions. Using muscle ultrasound we will be able to measure the size of the muscle in the thigh. In addition to the use and tolerability of BIA and muscle ultrasound in this group of patients we will be also taking other measurements including mid-arm circumference and physical tests (sitting to standing, walking speed and muscle strength). We will also use questionnaires to ask about symptoms relating to quality of life, physical activity and gastrointestinal symptoms. Patients will also provide a 3-day diet diary. We will be performing all of the above tests at the beginning before patients start the anti-fibrotic drugs and then again 4 months after starting the drugs and assessing for any changes over this period of time.