Glaucoma in patients with diabetes ups risk of diabetic retinopathy

Diabetic patients with primary open-angle glaucoma (POAG) are at greater risk of developing diabetic retinopathy (DR), reveals a study, noting the need for screening and comprehensive management in glaucomatous patients with diabetes to reduce the risk of DR.

Overall, 44,359 diabetic patients with POAG and 4,393,300 patients with diabetes without any glaucoma (aged ≥18 years) were included in this retrospective cohort study. After propensity score matching (adjusted for age, sex, race/ethnicity, blood markers, relevant medical history, and ophthalmic service use), 39,680 patients were left in each cohort, covering diagnosis from 1 January 2005 to 1 January 2023.

The investigators analysed data using specific International Classification of Diseases, 10th Revision (ICD-10) codes for diabetes and glaucoma. The primary outcome was the first-time occurrence of DR, including nonproliferative (NPDR) and proliferative DR (PDR) at 1-, 5-, and 10-year intervals from the individual index dates.

Patients with type 1 diabetes (T1D) and POAG showed an increased risk for any DR (adjusted risk ratio [RR], 4.12, 95 percent confidence interval [C], 3.05‒5.57; p<0.0001) and PDR (RR, 7.02, 95 percent CI, 3.62‒13.61; p<0.0001) at 10 years.

Similarly, patients with type 2 diabetes (T2D) and POAG had an increased risk for any DR (RR, 2.47, 95 percent CI, 2.28‒2.68; p<0.0001) and PDR (RR, 3.82, 95 percent CI, 3.09‒4.70; p<0.0001) at 10 years.

The combined association of POAG on DR risk in patients with T1D and T2D at 10 years was significantly greater among those with POAG than those without (5.45 percent vs 2.12 percent; adjusted hazard ratio, 2.33, 95 percent CI, 2.14‒2.53). Likewise, the cumulative incidence of DR was much higher in patients with POAG than those without (log-rank p<0.001).

“Future research should delve into elucidating the causal mechanisms driving these observed associations,” the investigators said.