ABSTRACT
Background and Objectives: Increased risk of venous thromboembolism is observed in several autoimmune inflammatory disorders. However, data on bullous pemphigoid, one of the most common autoimmune blistering disorders, is limited. This systematic review and meta-analysis was conducted to summarize all available evidence. Methods: Two investigators independently searched published studies indexed in MEDLINE and EMBASE from inception to July 2016 using the terms for bullous pemphigoid and venous thromboembolism. The inclusion criteria were as follows: (1) cohort or case-control study evaluated the association between bullous pemphigoid and risk of venous thromboembolism, (2) effect estimates were provided as odds ratios, relative risk, hazard ratio, standardized incidence ratio with 95% confidence intervals, and (3) subjects without bullous pemphigoid were used as comparators for cohort studies, while subjects without venous thromboembolism were used as comparators for case-control studies. Point estimates and 95% confidence intervals were extracted from each study and were pooled together using the random-effect model, generic inverse variance method of DerSimonian and Laird. Cochran's Q test and the I2 statistic were used to evaluate the statistical heterogeneity. Results: Two retrospective cohort studies, one prospective cohort study, and one case-control study met the eligibility criteria and were included in the meta-analysis. The pooled odds ratio was 2.69 (95% confidence interval, 1.79–4.05). Statistical heterogeneity was high with I2 of 77%. Limitation: Limited accuracy of diagnosis of primary studies and high between-study heterogeneity. Conclusion: This meta-analysis demonstrated that patients with bullous pemphigoid have a significantly increased risk of venous thromboembolism.