Association of Immunosuppressants with Mortality of Patients with Bullous Pemphigoid: A Nationwide Population-Based Cohort Study

Background: Bullous pemphigoid (BP) is a common autoimmune blistering skin disease with substantial mortality. Objective: To identify whether the use of immunosuppressants was associated with reduced mortality in BP patients. Methods: The data for this study were obtained from the National Health Insurance Research Database in Taiwan from January 1, 1997 to December 31, 2013. Those BP patients receiving any immunosuppressant for >= 28 days per month for 3 consecutive months were defined as the immunosuppressant cohort. In total, 452 BP patients on immunosuppressants were matched 1:4 by age, sex, propensity score of comorbidities, and use of tetracycline with 1,808 BP patients taking only corticosteroids. Results: The immunosuppressant cohort had a significantly lower 5-year mortality rate than the corticosteroid cohort (0.57 vs. 0.67). In the multivariable regression analysis adjusted for covariates, the use of immunosuppressants significantly reduced the risk of mortality (hazard ratio [HR]: 0.78, 95% confidence interval [CI]: 0.68-0.90, p < 0.001). Hyperlipidemia also reduced risk of mortality. However, age, diabetes, renal disease, chronic obstructive pulmonary disease, cerebrovascular disease, and dementia were significant risk factors for mortality. In the subgroup analysis, the risk of mortality decreased most substantially in those aged <70 years (HR: 0.45, 95% CI: 0.28-0.72). Conclusion: Immunosuppressant use was associated with a 22% reduced risk of BP mortality. The effects were more substantial in those aged <70 years, with a 55% reduced risk of mortality.