Association of serious infections with pemphigus and pemphigoid: analysis of the Nationwide Inpatient Sample.

BACKGROUND: Pemphigus and pemphigoid are blistering disorders associated with barrier disruption, immune dysregulation and use of immunosuppressing systemic therapy, all of which may predispose towards serious infections.

OBJECTIVES: To determine whether pemphigus and pemphigoid are associated with increased likelihood of serious infections and the impact of such infections on mortality and cost of care.

METHODS: We analysed data from the 2002 to 2012 Nationwide Inpatient Sample, including a representative 20% sample of all hospitalizations in the US (total n = 72 108 077 adults).

RESULTS: Overall, 54.6% (95% CI: 53.6-55.6%) and 50.4% (49.0-51.8%) of inpatients with either pemphigoid or pemphigus had a diagnosis of serious infection, respectively, compared with 25.4% (25.2-25.6%) in those without either diagnosis. In multivariable logistic regression models controlling for gender, age, race/ethnicity and insurance status, pemphigoid or pemphigus was associated with 26 or 21 of 48 infections examined, respectively. In particular, both pemphigoid and pemphigus were associated with higher odds of infections of the skin, bones, respiratory, gastrointestinal, genitourinary and central nervous system, septicaemia and antibiotic-resistant infections. Pemphigus was also associated with aspergillus, pharyngitis and Pneumocystis Carinii pneumonia. Associations of any serious infection in both pemphigoid and pemphigus patients were older age, non-White race, lower median household income, government or no insurance, higher number of chronic conditions, and those with a diagnosis of Cushing's syndrome, diabetes, cancer or autoimmune disease. The diagnosis of any serious infection vs. no infection was associated with increased inpatient mortality and costs in both pemphigoid (mortality: 7.85% vs. 2.84%; cost: $16 115 vs. $10 653) and pemphigus (mortality: 6.78% vs. 1.88%; cost: $17 707 vs. $11 545) inpatients (P < 0.0001 for all).

CONCLUSIONS: Adults with pemphigus or pemphigoid had increased cutaneous, respiratory, multi-organ and systemic infections, which were associated with considerable inpatient mortality and cost burden. Moreover, there were significant clinical and healthcare disparities with respect to infections in patients with pemphigus or pemphigoid.