Economic burden of comorbidities in patients with psoriasis is substantial

Background Psoriasis is frequently associated with comorbidities. Objective To estimate the incremental economic burden associated with comorbidities in patients with psoriasis, accounting for psoriasis severity. Methods Patients continuously enrolled >= 6 months after a randomly selected psoriasis diagnosis date were selected from the Ingenix Impact National Managed Care Database (1999-2004). Comorbidities identified during the 6-month study included: psoriatic arthritis, cardiovascular disease, depression, diabetes, hyperlipidemia, hypertension, obesity, cerebrovascular diseases and peripheral vascular disease. Resource utilization and costs during the 6-month follow-up period were compared for patients with >= 1 comorbidity vs. those without and for patients with a specific comorbidity vs. those without. Adjusted incidence rate ratios (IRRs) and odds ratios (ORs) were estimated for resource utilization using negative binomial and logistic regression models, respectively. Adjusted incremental costs associated with comorbidities were reported using general linear models with log-link and gamma distributions or two-part models. Models controlled for age, sex and psoriasis severity. Results A total of 114 512 patients were included; 51% had >= 1 comorbidity. Hyperlipidemia (27%) and hypertension (25%) were most prevalent. Patients with comorbidities were more likely to experience urgent care [OR (95% confidence interval (CI)) = 1.58 (1.51-1.65)] than patients without comorbidities. They also had significantly greater hospitalization rates [IRR (95% CI) = 2.27 (2.13-2.42)] and outpatient visits [IRR (95% CI) = 1.53 (1.52-1.55)]. Compared with patients who did not have comorbidities, patients with comorbidities incurred $2184 (P < 0.001) greater total costs. Conclusion Comorbidities present a significant economic burden in patients with psoriasis.