Factors Associated with Blindness in Patients with Type 2 Diabetes

William Gange, MD

Findings of a new study identify independent factors associated with the risk of blindness among newly diagnosed patients with type 2 diabetes.

Though only a small, significant number of patients developed blindness, the findings of the study highlighted the importance of screening eye exams from index diagnosis.

William Gange, MD, and colleagues determined demographic and socioeconomic risk factors associated with the development of blindness within the first 5 years after diagnosis of the disease. The findings were presented at the American Society of Retina Specialists (ASRS 2020) Virtual Sessions.

Gange and the team used a large nationwide medical claims database to recruit patients at least 40 years old with newly diagnosed type 2 diabetes from 2007-2015. Patients were required to have continuous enrollment in the study for 6 years—1 year before and 5 years after the index diabetes diagnosis. The team identified more than 71,000 newly diagnosed patients.

The investigators collected demographic data including age at diagnosis, gender, race, household income, education level, and Medicare versus private insurance. Blindness development was determined using ICD-9 codes.

The incidence of blindness 2 years after index was .55%. The rate increased 5 years after index diagnosis to 1.18%. Overall, 849 of 71.817 patients developed blindness at 5 years post-diagnosis.

There were many independent factors associated with the incidence of blindness within the first 5 years after index type 2 diabetes diagnosis. Patients who were older when they received their diagnosis were more likely to develop blindness (55-64 years old: OR, 1.36; 95% CI, 1.04-1.79; P=.025; at least 75 years old: OR, 1.83; 1.34-2.51; P <.001).

When comparing race, black race was more likely to become blind (OR, 1.38; 95% CI, 1.13-1.67; P=.001). Further, those with Medicare Advantage insurance had higher rates of blindness (OR, 1.85; 95% CI, 1.32-2.59; P <.001).

Patients who smoked (OR, 1.33; 95% CI, 1.1-1.6; P=.003), those with hypertension (OR, 1.56; 95% CI, 1.34-1.82; P <.001), those who used insulin (OR, 1.35; 95% CI, 1.11-1.63; P=.003), and patients with morbid obesity (OR, 1.39; 95% CI, 1.13-1.71; P=.002) were all at higher risk for developing blindness within 5 years of diagnosis. Those from lower-income backgrounds were also more likely to develop blindness.

The leading cause of blindness in working-age adults in the US is diabetic eye disease. With diabetes rates continuing to rise in the US, the investigators reported the importance of adequately screening all patients for diabetic retinopathy at guideline-recommended intervals, which remains a challenge.

“This study underscores the importance of screening eye exams from the initial diagnosis of (type 2 diabetes),” the investigators concluded.

The study, “Risk Factors for Rapid Progression to Blindness in a Large Sample of Newly-Diagnosed Type 2 Diabetics,” was presented at ASRS 2020.