Vision-Related Functional Burden of Diabetic Retinopathy Across Severity Levels in the United States

Abstract

Importance: Among adults with diabetes in the United States, severe forms of diabetic retinopathy (DR) are significantly associated with a greater vision-related functional burden.

Objective: To assess the functional burden of DR across severity levels in the United States.

Design, setting, and participants: This cross-sectional study was based on 1004 participants 40 years or older with diabetes and valid ocular and sociodemographic outcomes in the National Health and Nutrition Examination Surveys (NHANES) (2005-2006 and 2007-2008). Diabetic retinopathy was based on fundus photograph grading, using the Early Treatment Diabetic Retinopathy Study severity scale. The analysis was performed from October 15, 2016, to June 15, 2017.

Main outcomes and measures: Functional difficulties secondary to vision were assessed during a household questionnaire in which participants self-reported difficulty with reading, visuospatial tasks (ie, close-up work or finding things on a crowded shelf), mobility (ie, walking down steps, stairs, or curbs), and driving. The main outcome measure was vision-related functional burden, which was defined as present for individuals reporting moderate or greater difficulty in any of the aforementioned tasks.

Results: Of the 1004 persons with diabetes analyzed for this study (mean age, 65.7 years [95% CI, 64.0-67.3 years]; 51.1% male [95% CI, 47.1-55.2] and 48.9% female [95% CI, 44.8-52.9]), the prevalence was 72.3% for no retinopathy, 25.4% for mild and moderate nonproliferative diabetic retinopathy (NPDR), and 2.3% for severe NPDR or proliferative diabetic retinopathy (PDR). The prevalence of vision-related functional burden was 20.2% (95% CI, 16.3%-24.1%) for those with no retinopathy, 20.4% (95% CI, 15.3%-27.8%) for those with mild and moderate NPDR, and 48.5% (95% CI, 25.6%-71.5%) for those with severe NPDR or PDR (P = .02). In multivariable analysis, the odds of vision-related functional burden were significantly greater among those with severe NPDR or PDR relative to those with no retinopathy (adjusted odds ratio [aOR], 3.59; 95% CI, 1.29-10.05; P = .02). Those with severe NPDR or PDR did not have a statistically significant greater odds of vision-related functional burden than did those with mild or moderate NPDR (aOR, 2.70; 95% CI, 0.93-7.78; P = .07).

Conclusions and relevance: Among US adults with diabetes, approximately half of those with severe NPDR or PDR had difficulty with at least one visual function task. Moreover, vision-related functional burden was significantly greater among those with severe NPDR or PDR than among those with no retinopathy. These data suggest the importance of preventing severe forms of DR to mitigate the vision-related functional burden among US adults with diabetes. Future studies should complement our study by assessing the association of worsening retinopathy with objectively measured functional outcomes.

Figure 1.. Flowchart for Sampling of US Adults With Diabetic Retinopathy

Diabetes was defined based on an algorithm developed by Varma et al. Specifically, individuals were classified as having diabetes if they self-reported a history of diabetes based on the question, “Have you ever been told by a doctor or health professional that you have diabetes or sugar diabetes?” Individuals were also categorized as having diabetes if they had a glycosylated hemoglobin A_1c value of at least 6.5%, antidiabetic medication use according to the medication inventory file, or a positive response to the question “Are you now taking insulin?” or “Are you now taking diabetic pills to lower your blood sugar?” NHANES indicates National Health and Nutrition Examination Survey; NPDR, nonproliferative diabetic retinopathy; and PDR, proliferative diabetic retinopathy.

Figure 2.. Vision-Related Functional Burden Among US Adults With Varying Levels of Diabetic Retinopathy: National Health and Nutrition Examination Survey, 2005-2008

Error bars indicate 95% CIs. P value represents comparison across the 3 groups (severe NPDR or PDR vs mild and moderate NPDR vs no retinopathy). NPDR indicates nonproliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy.

Figure 3.. Vision-Related Functional Difficulties by Specific Activities Among US Adults With Varying Levels of Diabetic Retinopathy: National Health and Nutrition Examination Survey, 2005-2008

Error bars indicate 95% CIs. NPDR indicates nonproliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy. P values represent comparison across the 3 groups (severe NPDR or PDR vs mild and moderate NPDR vs no retinopathy).