Comorbidity risk of diabetic retinopathy and glaucoma from the IRIS registry

Abstract

Purpose : Diabetes mellitus (DM) has been identified as a risk factor for glaucoma, and previous studies have suggested an association between diabetic retinopathy (DR) and glaucoma. The purpose of this study was to assess the comorbidity risk of DR and glaucoma on a population level using the American Academy of Ophthalmology’s IRIS Registry (Intelligent Research in Sight).

Methods : In this retrospective study, all patients of at least 50 years of age with an ICD-10 diagnosis documented in 2017 were included. Patients with a diagnosis of DR were subdivided according to their DR type: Type 1 DM (E10.3) or Type 2 DM (E11.3) with unspecific DR, mild to severe non-proliferative DR, and proliferative DR. The comorbidity risk ratio (cRR) was calculated for (1) all types of glaucoma, including suspects (H40.*), (2) open-angle glaucoma (OAG; H40.1), and (3) primary angle closure glaucoma (PACG; H40.2). The cRR was defined as the probability of having glaucoma while being diagnosed with DR, divided by the probability of having glaucoma without a diagnosis of DR. P values were calculated using Fisher’s exact test. All statistical analyses were performed using R.

Results : A total of 15,907,109 patients were selected (mean age: 68.5 years, 41.1% male). Of these, 2,853,400 (17.9%) had a form of glaucoma, and 1,142,408 (7.2%) had DR due to Type 1 or Type 2 DM (see Fig. 1 for details). Fig. 2 illustrates the cRR results: there was a significantly increased risk of all 3 glaucoma conditions for those with any stage of DR compared to those without DR (cRRs between 1.02 and 5.63, all P<0.001). The highest comorbidity risks were seen with PACG: the cRR peaked for severe non-proliferative DR at 5.63 (95% CI: [5.33, 5.96], P=0) and decreased for proliferative DR to 2.68 (95% CI: [2.56, 2.80], P=8.85 x 10^-301; values shown for Type 2 DM). For OAG, a higher comorbidity risk was seen with proliferative DR than with non-proliferative DR in Type 2 DM, while no clear effects of DR severity were noted in Type 1 DM.

Conclusions : There is a significantly increased comorbidity risk of glaucoma with both proliferative and non-proliferative DR at all stages. The risk is particularly pronounced for PACG, with those with severe non-proliferative DR having a 5-to-6-fold higher risk of PACG than those without DR.

This is a 2020 ARVO Annual Meeting abstract.

 

Figure 1. Demographic and clinical characteristics of the study population.

 

Figure 2. Comorbidity risk ratios for glaucoma and different stages of DR.