Global incidence and prevalence of bullous pemphigoid: A systematic review and meta-analysis

Background Integrated information on the global prevalence and incidence of bullous pemphigoid (BP) is lacking. Objective To estimate the incidence and prevalence of BP in a systematic review and meta-analysis. Methods Observational studies were included by using databases of Medline, EMBASE, and Cochrane Library. Subgroup analysis was by continent, age, sex, and country income level. Random-effects model was used. Between-study heterogeneity was assessed using the I-2 statistic. Results The global incidence was 0.0419 per 1000 person-years (95% CI: 0.0414-0.0424). The incidence was 0.047 per 1000 person-years (95% CI: 0.0462-0.0477), 0.0419 per 1000 person-years (95% CI: 0.0411-0.0426), 0.0072 per 1000 person-years (95% CI: 0.0067-0.0078), 0.003 per 1000 person-years (95% CI: 0.0023-0.0039) in North America, Europe, Asia, and Africa, respectively; 0.0202 per 1000 person-years (95% CI: 0.0196-0.0208) and 0.0181 per 1000 person-years (95% CI: 0.0175-0.0188) females and males; 0.001 per 1000 person-years (95% CI: 0.001-0.001), 0.002 per 1000 person-years (95% CI: 0.001-0.002), 0.004 per 1000 person-years (95% CI: 0.004-0.004); 0.007 per 1000 person-years (95% CI: 0.007-0.008), 0.011 per 1000 person-years (95% CI: 0.011-0.012), 0.017 per 1000 person-years (95% CI: 0.015-0.018) for age <50, 50-59, 60-69, 70-79, 80-89, and >= 90 years; 0.0038 per 1000 person-years (95% CI: 0.0036-0.004112) (I-2 = 99%, p < .05) and 0.0456 per 1000 person-years (95% CI: 0.0450-0.0462) (I-2 = 100%, p < .05). The pooled clinic-based prevalence was 0.79% (95% CI: 0.75%-0.84%), 1.13% (95% CI: 1.06%-1.21%), 0.21% (95% CI: 0.17%-0.26%), and 0.13% (95% CI: 0.1%-0.15%) for Asia, Africa, and Europe. Conclusions This study identified the global incidence and prevalence of BP in terms of spatial and population distributions and among various income level. A relatively higher incidence was in Europe, females, older people, and high-income level country. The prevalence was higher in Asia. These findings should be interpreted with caution due to high heterogeneity of included studies.