Determinants of adherence to sirolimus among lymphangioleiomyomatosis patients

Lymphangioleiomyomatosis (LAM) is a low-grade malignant neoplasm characterized by multisystem involvement. Patients with LAM require long-term sirolimus therapy to slow disease progression, yet poor adherence to this medication may lead to reduced lung function and disease deterioration. The objective of this study is to comprehensively characterize sirolimus adherence in patients with LAM. Specifically, it aims to identify factors associated with poor adherence, explore determinants of self-reported adherence, and compare changes in pulmonary function over 2 years across adherence groups. We conducted a questionnaire survey of patients diagnosed with LAM (n = 133). We used the 8-item Morisky Medication Adherence Scale (MMAS-8) to assess medication adherence, the Brief Illness Perception Questionnaire (BIPQ) to assess illness perceptions, the Social Support Rating Scale (SSRS) to assess social support, and the Hospital Anxiety and Depression Scale (HADS) to assess anxiety and depressive symptoms. Multivariate logistic regression was then performed to identify risk factors influencing sirolimus adherence among LAM patients. Furthermore, we compared changes in lung function over the two-year follow-up period. In our cohort, 20.3% of LAM patients demonstrated high medication adherence, 41.5% moderate adherence, and 38.1% poor adherence. Additionally, educational level, FEV1/FVC (% predicted), the number of adverse drug reactions ≥ 3, BIPQ scores and anxiety symptoms are associated with medication adherence. Furthermore, patients with better medication adherence showed greater improvements in lung function, exercise endurance, and disease activity than those with poor adherence. Over one-third of LAM patients reported poor medication adherence. High FEV1/FVC (% predicted), high BIPQ scores, comorbid anxiety, and low educational level are risk factors. These may help identify LAM patients with poor medication adherence early.