Low Body Mass Index as a Predictor of Amiodarone-Induced Pulmonary Toxicity

Amiodarone-induced pulmonary toxicity (APT) is one of the major side effects of the medication when used in the treatment of arrhythmia. However, the risk factors for developing APT have yet to be fully understood.

We retrospectively analyzed 454 patients who were treated with amiodarone for arrhythmia between 2016 and 2020 at the National Cerebral and Cardiovascular Center, Osaka, Japan. During the median follow-up period of 207 days, 24 patients (5.4%) had APT. Using a multivariate analysis of the Cox proportional hazards model, lower body mass index (BMI) (hazard ratio [HR]: 0.81, 95% confidence interval [CI]: 0.71-0.95), higher age (HR: 1.06, 95% CI: 1.02-1.10), and higher amiodarone maintenance dose (HR: 1.01, 95% CI: 1.003-1.02) were risk factors for APT. Specifically, the patients whose BMIs were < 22 kg/m² were approximately three times more likely to develop APT than the patient whose BMIs were ≥ 22 kg/m². The cutoff value for maximum KL-6 levels during amiodarone therapy as an APT screening test was 444 U/mL or higher, with a sensitivity of 70.8% and specificity of 88.1%.

Lower BMI, higher age, and a higher maintenance dose were identified as independent risk factors for APT. KL-6 levels during administration may be useful in suspecting the development of APT.