Neurological Cancer is a Risk Factor for Bullous Pemphigoid: 11-Year Population-Based Cohort Study

Background: There is evidence suggesting an association between bullous pemphigoid (BP) and a range of neurological diseases. Whether neurological cancer is a risk factor for BP remains unknown. Objective: The aim of the study was to investigate the risk of subsequent BP among patients with neurological cancer. Methods: This nationwide population-based cohort study was based on data obtained from the Taiwan National Health Insurance Research Database between 2000 and 2012. A total of 8313 patients with neurological cancer and 33,252 age-, sex-, and index-date-matched controls were recruited. The hazard ratio (HR) for subsequent BP in patients with neurological cancer was analyzed using a Cox model and Fine-Gray competing risk model, with mortality as the competing event. Results: The incidence rates of BP per 100,000 person-years were 37.2 for patients with neurological cancer and 6.8 for controls. The crude incidence rate ratio was 5.49 (95% confidence interval [CI] 2.18–13.30). The mean time to occurrence of BP was 4.48 ± 3.40 years for patients with neurological cancer. Neurological cancer (HR 9.65, 95% CI 3.76–24.77 for the Cox model; HR 2.41, 95% CI 1.14–5.14 for the competing risk model), age per year (HR 1.10, 95% CI 1.05–1.15 for the Cox model; HR 1.06, 95% CI 1.02–1.09 for the competing risk model), and dementia (HR 6.31, 95% CI 2.49–15.99 for the Cox model; HR 7.50, 95% CI 2.84–19.85 for the competing risk model) significantly increased the risk of BP. Conclusions: Neurological cancer increased the risk for subsequent BP by 2.4-fold, with a relatively short gap of 4.5 years.