Psoriasis and risk of diabetes-associated microvascular and macrovascular complications

Background Psoriasis's effect on diabetes onset is well documented, but its effect on course of diabetes is poorly understood. Objective We sought to compare risks of developing microvascular and macrovascular complications between diabetic patients with and without psoriasis. Methods Adults with 2 or more diabetes diagnoses selected from MarketScan databases (Truven Health Analytics Inc, Ann Arbor, MI) (2000-2006) were classified into 2 cohorts: 2 or more psoriasis diagnoses and without psoriasis diagnosis. Patients with psoriasis were matched using propensity score, and exactly matched using age, sex, and diabetes characteristics with patients without psoriasis. Outcomes were compared between cohorts using Cox regression models. Results In all, 6164 diabetic patients with psoriasis (27% moderate to severe) were matched to 6164 diabetic patients without psoriasis. Patients with psoriasis were significantly more likely to develop microvascular events than patients without psoriasis overall (hazard ratio [HR] 1.14, P <.001) and by psoriasis severity (mild: HR 1.13, P =.004; moderate to severe: HR 1.16, P =.038). Risk of macrovascular events was higher for patients without psoriasis overall (HR 1.13, P =.001) and those with mild psoriasis (HR 1.15, P =.003), but not for moderate to severe cases (HR 1.10, P =.210). Limitations Psoriasis to diabetes association may be underestimated. Conclusion Among diabetic patients, psoriasis is generally associated with higher rates of microvascular and macrovascular complications. Greater psoriasis severity did not increase risk of diabetic complications.