Psoriasis as a Predictor of Neovascular Age-Related Macular Degeneration in Type 2 Diabetes Mellitus: A Nationwide Cohort Study

The objective of this study is to evaluate the relationship of psoriasis and neovascular age-related macular degeneration (nAMD) in a population with diabetic mellitus (DM). Nationwide, population-based, retrospective cohort study. Records of patients over 40 years of age who had been diagnosed with type 2 diabetes mellitus from January 2009 to December 2012 were analyzed. The incidence of nAMD was observed from the index year to December 2018 in all subjects. The incidence rate of nAMD was compared between the psoriasis group and control group. Covariates include age, sex, body mass index, income level, smoking status, drinking status, regular exercise habits, hypertension, dyslipidemia, end-stage renal disease, diabetic retinopathy, glucose level, prescription of more than 3 oral hypoglycemic agents, and a history of diabetes mellitus exceeding 5 years. Of 2,245,358 patients with type 2 DM, 20,853 patients were classified in the psoriasis group and the other 2,224,505 in the control group. A total of 105 nAMD cases were observed in the psoriasis group and 7459 cases in the control group. According to multivariable Cox proportional hazard models, individuals with psoriasis had a significantly higher risk for nAMD compared to controls (hazard ratio = 1.329, 95% CI = 1.096-1.612) after adjustments for covariates. This study demonstrated that psoriasis was an independent risk factor for developing nAMD in DM patients. Therefore, physicians should be alert to the development of nAMD in DM patients who also have psoriasis.