Relationship between bullous pemphigoid and metabolic syndrome: a 12-year case control study conducted in China

Background: Hypertension, diabetes, dyslipidemia, and obesity are prevalent in patients with bullous pemphigoid (BP) and are all components of metabolic syndrome (MS). However, the prevalence of MS in patients with BP is unknown. We aimed to evaluate the relationship between MS and BP and to define the clinical and laboratory characteristics of patients with both conditions. Methods: This retrospective case-control study was conducted for 12 years at Peking Union Medical College (162 with BP and 162 age and sex-matched controls). The components of MS were analyzed and logistic regression was used to identify independent risk factors for BP. In addition, the clinical and laboratory characteristics of patients with BP +/- MS were compared. Results: The prevalence of MS in patients with BP was 35.2% and that in controls was 14.8% (p <0.0011. After adjustment for sex and age, multivariate analysis demonstrated a positive correlation between BP and MS [odds ratio (OR) 2.490, 95% confidence interval (CI) 1.040-5.963], diabetes (OR 1.870, 95% CI 1.029-3.3961, and overweight or obesity (OR 1.807, 95% CI 1.026-3.182). In the BP group, participants with MS were older (p = 0.006), were less likely to present erythema (p = 0.028), and had higher serum C3 (p = 0.007) and incidence of infection within 1 year of their diagnosis (p = 0.035) than participants without MS. Conclusion: MS and its components hyperglycemia and overweight were found to be independently associated with BP. Therefore, clinicians should screen for MS in patients with BP, especially if they are older, present less erythema, or have a high serum C3.