Prevalence and assessment of exercise-induced desaturation in lymphangioleiomyomatosis

Exercise-induced desaturation is poorly recognised in lymphangioleiomyomatosis (LAM) and its relationship to outcome is unknown. In a UK cohort study, 37% of 131 women with LAM experienced exercise-induced desaturation to <88% during a 6 min walk test. Forced expiratory volume in 1 s (FEV₁) and DL_CO were associated with walk parameters but had poor predictive accuracy for exercise-induced desaturation. A 5-year follow-up showed exercise-induced desaturation at baseline was associated with rapid FEV₁ decline (p=0.008) and need for rapamycin treatment (p=0.00001). Women with LAM should be evaluated for exercise-induced desaturation to target ambulatory oxygen and improve identification of those at risk of poor outcomes.