Multiple or Single Endocrine Abnormalities Associated With Immune Checkpoint Inhibitors.

[BACKGROUND] Immune checkpoint inhibitors (ICIs) are associated with various endocrine abnormalities. However, their underlying pathophysiology remains unclear. We investigated the effect of multiple endocrine abnormalities on the overall survival (OS) of patients treated with ICIs.

[METHODS] In total, 12 978 patients who received ICIs between 2014 and 2022 were investigated using the DeSC Japanese administrative claims database. Endocrine abnormalities were defined by each hormone replacement therapy, including levothyroxine, hydrocortisone, and insulin, in which it is difficult to distinguish central or primary hormone defect. Also, only patients with hypothyroidism after thyroiditis were included. Type 1 diabetes was additionally defined by the name of the disease and strict self-injection fees. Regression analyses were performed to identify risk factors for endocrine abnormalities and the effect of endocrine abnormalities on OS, adjusting for confounders including the number and duration of ICI administrations.

[RESULTS] Single and multiple endocrine abnormalities were observed in 12.0% and 1.4% of patients, respectively. The most common combination was hypothyroidism and adrenal insufficiency (1.3%). Kaplan-Meier analysis indicated better survival in patients with multiple and single endocrine abnormalities than in those without (P < .01). Multivariable analysis revealed lower mortality in patients with multiple and single endocrine abnormalities [adjusted hazard ratio (aHR) 0.39; 95% confidence interval (CI), 0.28-0.54, P < .01; aHR 0.65; 95% CI, 0.5-80.72, P < .01, respectively) than in those without. Mortality was significantly lower with multiple abnormalities than with single (aHR 0.56; 95% CI, 0.39-0.79, P < .01).

[CONCLUSION] The development of multiple endocrine abnormalities in patients treated with ICIs is associated with improved survival compared with that of patients with a single abnormality.