Diabetes-Related Risk Factors for Exudative Age-Related Macular Degeneration: A Nationwide Cohort Study of a Diabetic Population

Abstract

Purpose: The purpose of this study was to identify diabetes-related risk factors for exudative age-related macular degeneration (AMD).

Methods: This was a nationwide population-based cohort study using authorized clinical data provided by the Korean National Health Insurance Service. A total of 1,768,018 participants with diabetes over 50 years of age participated in the Korean National Health Screening Program between 2009 and 2012. Data on covariates, including age, sex, income level, systemic comorbidities, behavioral factors, and diabetes-related parameters, including duration of diabetes, use of insulin for diabetes control, number of oral hypoglycemic agents used, and accompanying vision-threatening diabetic retinopathy, were collected from health screening results and claims data. Patients were followed up until December 2018. Incident cases of exudative AMD were identified using registered diagnostic codes from the claims data. The prospective association of diabetes-related parameters with incident exudative AMD was investigated using the multivariable-adjusted Cox proportional hazard model.

Results: During an average follow-up period of 5.93 years, 7331 patients were newly diagnosed with exudative AMD. Compared to those who had diabetes for less than 5 years, individuals with diabetes for 5 years or more had a greater risk of future exudative AMD development, with a hazard ratio (95% confidence interval) of 1.13 (1.07-1.18) in the fully adjusted model. Use of insulin for diabetes control and the presence of vision-threatening diabetic retinopathy were also associated with an increased risk of exudative AMD with a hazard ratio (95% confidence interval) of 1.16 (1.07-1.25) and 1.40 (1.23-1.61), respectively.

Conclusions: A longer duration of diabetes, administration of insulin for diabetes control, and comorbid vision-threatening diabetic retinopathy were associated with an increased risk of developing exudative AMD.

Figure 1.

Flow chart of the cohort study design.

Figure 2.

Association of diabetes-related variables with incident exudative age-related macular degeneration in subgroups by age and sex. Exudative age-related macular degeneration risks were estimated using the Cox proportional hazards model, adjusted for demographic factors, systemic comorbidities, and behavioral factors. (A) Significant interaction existed between insulin usage and age (P = 0.007) and vision-threatening diabetic retinopathy and age (P = 0.013) in development of exudative age-related macular degeneration. (B) No significant interactions were observed, and the associations were consistent in subgroup analyses by sex.