LAUSR

BACKGROUND Few large-scale and controlled studies examined the associations and predictors of the gamut of autoimmune conditions in pemphigus and pemphigoid. OBJECTIVE To examine associations of pemphigus or pemphigoid with autoimmune disorders and related outcomes in adults. METHODS Data from the 2002-2012 National Inpatient Sample were analyzed, including a ∼20% sample of all US hospitalizations (n=72,108,077 adults). RESULTS In multivariable logistic regression models, pemphigus (adjusted odds ratio [95% confidence interval]: 1.46 [1.30-1.63]) and pemphigoid (1.35 [1.24-1.48]) were associated with ≥1 autoimmune disorder. Pemphigus and pemphigoid were associated with 9 of 29 and 13 or 32 autoimmune disorders examined in bivariable models. Among pemphigus inpatients, unspecified autoimmune disease, vitiligo, eosinophilic esophagitis, and myasthenia gravis had the strongest effect-sizes. Whereas, among pemphigoid inpatients, unspecified autoimmune disease, vitiligo, and chronic urticaria had the strongest effect-sizes. There were significant differences of autoimmune comorbidities by age, sex and race/ethnicity. There were an estimated $2,286,588 and $4,301,681 excess annual costs of hospital care attributed to autoimmune disorders among inpatients with pemphigus and pemphigoid, respectively. LIMITATIONS Lack of treatment history data. CONCLUSIONS Inpatients with pemphigus or pemphigoid had increased odds of multiple cutaneous, extra-cutaneous and systemic autoimmune disorders, which were associated with a considerable cost-burden.