Short article: Crohn's disease and pemphigus: is there an association?: a population-based study.

BACKGROUND: Although the coexistence of Crohn's disease (CD) and pemphigus has been reported in several individuals, the association between the two conditions was not investigated systematically in the past. A recent association between pemphigus and ulcerative colitis has been reported. The study aims to estimate the association between pemphigus and CD using a large-scale real-life computerized database.

PATIENTS AND METHODS: A cross-sectional study was carried out comparing pemphigus patients with age-matched, sex-matched, and ethnicity-matched control participants in terms of the prevalence of CD. χ-Test and t-test were used for univariate analysis and a logistic regression model was used for multivariate analysis. The study was carried out utilizing the computerized database of Clalit Health Services ensuring 4.5 million patients.

RESULTS: A total of 1985 pemphigus patients and 9874 controls were included in the study. The prevalence of CD was comparable in patients with pemphigus and controls [0.4 vs. 0.3%, respectively; odds ratio (OR): 1.2; 95% confidence interval (CI): 0.5-2.5; P=0.688]. In an age-stratified analysis, a significant association was observed between pemphigus and CD in patients younger than 40 years (2.1 vs. 0.4%, respectively; OR: 5.1; 95% CI: 1.0-25.7; P=0.027). In a multivariate analysis adjusting for potential confounding factors, no independent association between the two conditions was found (OR: 0.9; 95% CI: 0.4-2.0; P=0.828). Study findings were robust to sensitivity analysis that included patients under pemphigus-specific treatments.

CONCLUSION: Unlike ulcerative colitis, CD was not associated with pemphigus. Further research is warranted to understand the pathophysiology of these observations better.