Inhaled Corticosteroid Increased the Risk of Adrenal Insufficiency in Patients with Chronic Airway Diseases: A Nationwide Population-based Study

Abstract Inhaled corticosteroids (ICS) are commonly used for airway disease, but concerns about adrenal insufficiency (AI) have arisen. This study investigated the link between ICS use and AI risk using data from the National Health Insurance Service-National Sample Cohort, analyzing 66,631 patients with COPD or asthma (mean age: 57.3 years, 42.6% male). ICS use, daily dosage, and AI cases were identified via diagnostic codes. Cox proportional survival analysis and inverse probability of treatment weighting (IPTW) addressed baseline differences between ICS and non-ICS users. Among the patients, 15.5% used ICS, with AI incidence higher in ICS users (1.69 per 1000) than in non-users (0.54 per 1000). ICS use independently increased AI risk (HR: 3.06, 95% CI: 1.82–5.14). Each 100 µg/day increase in ICS was associated with a 3% increase in AI incidence (HR: 1.03, 95% CI: 1.02–1.04). Quartile analysis before IPTW indicated a significant AI risk increase across all ICS dosage quartiles compared with non-users. Subgroup analysis showed consistent associations with age, sex, and smoking, with stronger links in systemic steroid users and those with higher Charlson comorbidity index (CCI). ICS use increases AI risk in chronic airway disease patients, particularly among systemic steroid users and those with higher CCI.