Association between bullous pemphigoid and malignancy: A meta‐analysis

It has been suggested that bullous pemphigoid is associated with an increased risk of malignancy, but the evidence is inconsistent. Therefore, a meta-analysis was conducted to explore this association. PUBMED and Embase were searched for studies investigating the association between bullous pemphigoid and malignancy. This meta-analysis included 16 studies with a total of 9398 cases of bullous pemphigoid. The rate of malignancy in patients with bullous pemphigoid was 11% (95% CI: 9-14, P < 0.001); 9% (95% CI: 6-13, P < 0.003) for women and 13% (95% CI: 9-18, P < 0.03) for men, with a statistically insignificant higher risk in men (OR = 1.30, 95% CI: 0.99-1.71, P = 0.06). The event rate was 9% (95% CI: 5-14, P < 0.001) in the Asian population and 13% (95% CI: 10-17, P < 0.001) in the European population, with a statistically significant lower risk in the Asians population (OR = 0.69, 95% CI: 0.57-0.84; P < 0.001). The event rate of malignancy was higher in patients with bullous pemphigoid than in matched controls (OR = 2.08, 95% CI: 1.22-3.55; P = 0.005). The overall event rate of malignancy was higher in the bullous pemphigoid group than in matched controls. Caution is required when interpreting these results, as potential confounding variables were not controlled for.