Lower muscle mass is related to poorer clinical outcomes in moderate to severe asthma

Background: In asthma, data on body composition, and especially muscle mass are scarce. Fat free mass was shown to be low in severe asthma, but the impact of low muscle mass on asthma outcomes is unknown. Aim: To explore associations between muscle mass and clinical outcomes in moderate to severe asthma. Methods: Muscle mass was assessed by fat free mass index (FFMI) using bio-impedance analyses, and creatinine excretion in 24h urine. Associations of muscle mass with clinical outcomes (asthma control (ACQ), quality of life (AQLQ), exacerbations, FEV1, blood eosinophils) were assessed with correlation coefficients. Results: We included 60 GINA 3-5 asthma patients (19 men, BMI 27±5 kg/m2). Different patient characteristics (e.g. age, smoking, medication use) did not affect FFMI or creatinine, except sex, with higher levels of FFMI (20.9±2.0 vs 17.1±2.0 kg/m2, p Conclusion: We found lower muscle mass to be related to poorer asthma outcomes and higher blood eosinophils in GINA 3-5 asthma. The mutual impact of systemic inflammation, muscle mass and asthma outcomes requires more research.