In the study, psoriasis was a risk factor for neovascular AMD even after adjusting for age, sex, BMI, income level, smoking and drinking status, regular exercise habits, hypertension, dyslipidemia, end-stage renal disease, diabetic retinopathy, glucose level, more than three oral hypoglycemic agents and a history of diabetes mellitus greater than five years. Photo: Cleveland Clinic. Click image to enlarge.

At first glance, a skin condition like psoriasis and neovascular AMD appear unrelated. However, research has shown that there may be an association between these two diseases, particularly in their manifestations of vascularity. A study published recently in American Journal of Ophthalmology evaluated this relationship in Korean patients with type 2 diabetes and reported that psoriasis is a risk factor for this progressive retinal condition.

For the nationwide cohort study, the researchers assessed more than 2.2 million health records of patients with type 2 diabetes over the age of 40. They classified these patients into a psoriasis group consisting of 20,853 subjects and a control group of 2,224,505 individuals. A total of 105 neovascular AMD cases occurred in the psoriasis group and 7,459 in the control group. Statistical analysis showed that patients with psoriasis had a significantly higher risk for neovascular AMD than controls (hazard ratio: 1.329).

The researchers hypothesized that psoriasis and neovascular AMD have a shared pathogenic mechanism. “Psoriasis is characterized by the rapid proliferation of skin cells resulting in red, scaly plaques and histologic markers of psoriasis includes accentuated vascularity in the dermis,” the researchers wrote in their AJO paper. “One of the pathogenic mechanisms in psoriasis is stimulation of angiogenesis induced by VEGF, hinting at a potential, yet underexplored, association between the psoriasis and neovascular AMD.”

Their present study in patients with type 2 diabetes showed that psoriasis is an independent risk factor for developing neovascular AMD. “Physicians should be alert for the development of neovascular AMD in diabetes mellitus patients who also have psoriasis,” they concluded.