Cancer is not a risk factor for bullous pemphigoid: 10-year population-based cohort study

BackgroundBullous pemphigoid (BP) is the most common autoimmune bullous disease. Whether there is an increased risk for subsequent BP among patients with cancer is still unclear. ObjectivesTo evaluate the risk for subsequent BP in patients with cancer. MethodsThis nationwide population-based cohort study was based on data obtained from the Taiwan National Health Insurance Database between 2000 and 2011. A total of 36 838 patients with cancer and 147 352 age-, sex- and index-date-matched controls were recruited. The hazard ratio (HR) of subsequent BP in the patients with cancer was analysed using a Fine-Gray competing risk regression model with mortality as the competing event. ResultsThe incidence of BP per 100 000 person-years was 172 in the patients with cancer and 198 in the controls; therefore, the crude incidence rate ratio was 087 [95% confidence interval (CI) 053-136]. The HR of subsequent BP in the patients with cancer was 047 (95% CI 023-094) using the Fine-Gray competing risk regression model. Age (HR 105, 95% CI 103-107), diabetes mellitus (HR 169, 95% CI 110-259) and cerebrovascular disease (HR 214, 95% CI 136-334) were independent risk factors for BP. ConclusionsThe incidence of BP in patients with cancer was not higher than in the control group. Cancer is not a risk factor for BP.