Association of psoriasis and stroke in end-stage renal disease patients

Background: Previous research in the general population suggests that the inflammatory skin disease psoriasis is associated with an increased risk of vascular events, such as stroke. Thus, psoriasis may also represent a risk factor for stroke in end-stage renal disease (ESRD) patients. Methods: We queried the United States Renal Data System for incident dialysis patients between 2004 and 2015. Psoriasis was defined as having at least two international classification of disease (ICD)-9 or ICD-10 diagnosis codes. ICD codes were also used to query the outcome of interest, stroke, as well as other clinical risk factors. Logistic regression was used to examine the association of psoriasis and other risk factors with stroke. Results: Of 966,399 ESRD patients, we identified 89,700 (9.3%) subjects with stroke and 6,286 (0.7%) with psoriasis. Of these psoriasis patients, 796 (0.9%) also had a stroke. Psoriasis was associated with an increased risk of stroke in an unadjusted model [odds ratio (OR)=1.16; 95% confidence interval (CI)=1.08–1.25]. However, after controlling for demographic and clinical risk factors, the final adjusted model showed that psoriasis was not associated with stroke (OR=0.96, CI=0.88–1.04). Congestive heart failure [adjusted OR of 1.79 (CI=1.75–1.83)] was a confounder of the association of psoriasis with stroke. Conclusions: Contrary to prior research in the general population, psoriasis in ESRD patients was not associated with the risk of stroke after controlling for various demographic and clinical parameters. Our finding emphasizes the importance of controlling for a variety of factors in population studies examining associations of diseases and risk factors.