Incidence of bullous pemphigoid and mortality of patients with bullous pemphigoid in Olmsted County, Minnesota, 1960 through 2009

Background: Bullous pemphigoid (BP) is an autoimmune blistering disease that is associated with increased mortality. Objective: We sought to determine the incidence and mortality of patients with BP. Methods: A total of 87 residents of Olmsted County, Minnesota, were identified who had their first lifetime diagnosis of BP from January 1960 through December 2009. Incidence and mortality were compared with age- and sex-matched control patients from the same geographic area. Results: The adjusted incidence of BP was 2.4 per 100,000 person-years (95% confidence interval, 1.9-2.9). Incidence of BP increased significantly with age (P < .001) and over time (P = .034). Trend tests indicate increased diagnosis of localized disease (P = .006) may be a contributing factor. Survival observed in the incident BP cohort was significantly poorer than expected (P < .001). Survival was not different among patients with multisite versus localized disease (P = .90). Limitations: Retrospective study design and study population from a small geographic area are limitations. Conclusion: Incidence of BP in the United States is comparable with that found in Europe and Asia. The mortality of BP is lower in the United States than Europe, but higher than previous estimates.