191 Increased risk of serious infection among patients with psoriasis: A population-based cohort study in the United Kingdom

Abstract

Infection is the second leading cause of death among psoriasis patients on phototherapy or systemic medications. The types of infection risk associated with psoriasis remain poorly understood. The aim of our study was to determine the risk of serious infection (i.e., requiring hospitalization) among patients with psoriasis. We conducted a cohort study of patients with (N=199,700) and without (N=954,315) psoriasis in The Health Improvement Network electronic medical record database. Patients receiving phototherapy or systemic therapy were considered to have severe psoriasis (N=12,442). The serious infection outcome was defined by a diagnostic code for a prespecified group of infections and documentation of hospitalization within 30 days of the infection date. The incidence rates of serious infection were 88.9, 85.7, and 145.7 per 10,000 person years for all patients with psoriasis and those with mild and severe disease, respectively, versus 78.5 per 10,000 person years for those without psoriasis. The most common types of serious infections among patients with psoriasis were lower respiratory, skin and soft tissue, and upper respiratory infections with incidence rates of 29.0, 16.4, and 16.3 per 10,000 person years, respectively. In multivariable analyses adjusting for age, gender, body mass index, smoking, systemic corticosteroids, flu or pneumonia vaccinations, prior infection or hospitalization, and comorbid disease including asthma/chronic obstructive pulmonary disease, diabetes, chronic kidney disease, and cardiovascular diseases, we found an increased risk of serious infection among patients with versus without psoriasis: hazard ratio 1.20 (95% confidence interval, 1.18-1.23). The risk was greater among those with severe psoriasis: mild, 1.19 (1.16-1.22); and severe psoriasis, 1.73 (1.61-1.86). Our results suggest serious infection, particularly respiratory and skin/soft tissue infections, to be an important and common cause of morbidity among patients with psoriasis, especially those with more severe disease.