Bullous Pemphigoid-Associated Mortality Rate in a Canadian Tertiary Referral Centre

Background Bullous pemphigoid (BP) is the most common autoimmune blistering disorder in adults. Most individuals with BP are over the age of 60. Its worldwide incidence has been increasing owing to population aging. Observational studies published over the last 2 decades highlight the non-negligible, albeit variable overall mortality of BP patients, with reported 12-month mortality rates of 10.8% to 40.8%, and 24-month mortality rates of 20.1% to 51.0%. Data in the Canadian population are lacking. Objectives We aimed to estimate the 12- and 24-month overall mortality rate of Canadian patients diagnosed with BP, and to identify independent risk factors adversely impacting overall survival. Methods A retrospective cohort study of 166 patients with a diagnosis of BP between 2010 and 2020 was carried out at Centre hospitalier de l'Universite de Montreal (CHUM), a tertiary referral center in Montreal, Quebec, Canada. Cumulative mortality was calculated using the Kaplan-Meier estimator, and independent prognostic factors were identified using a Cox proportional hazards regression model. Results Eighty-five patients (51.2%) in our study were female. The median age was 79.1 years old, and 80 patients (48.2%) were 80 years old or older. Mortality at 12 and 24 months in our study cohort was 16.2% (CI95% = 10.5 - 21.8) and 27.6% (CI95% = 20.5 - 34.7), respectively. In a multivariate analysis, patients who were male, 80 years old or older, and/or had a diagnosis of a major neurocognitive disorder had a poorer overall survival. Conclusions The all-cause mortality of patients with BP in our study population compared favorably with international data reported in the literature.