Revised blood sugar levels may predict development of retinal disease in patients with Diabetes

New hyperglycemia thresholds may predict the onset of retinopathy more accurately than the standard benchmarks in patients with diabetes mellitus, a study has found.

The current definition of diabetes is a fasting plasma glucose (FPG) level of 126 mg/dL or higher.

"We propose that thresholds of 108 mg/dL for FPG, and concentration of 6% for [hemoglobin A1C] level could be used to define those who are at risk of retinopathy," the study authors said.

The Data From an Epidemiological Study on Insulin Resistance Syndrome Study included 700 patients, ranging in age from 30 to 65 years. The patients were recruited between 1994 and 1996, and underwent health examinations at 3, 6 and 9 years after enrollment.

At 9 years, 235 patients had been treated for diabetes or had FPG levels of 126 mg/dL or higher, 227 patients had an impaired fasting glucose level of 110 mg/dL to 125 mg/dL at least once, and 238 patients had glucose levels lower than 110 mg/dL.

A non-mydriatic digital retinal camera was used to obtain high-resolution retinal images at 10 years. Retinopathy was identified in 44 patients.

Study results showed that patients with retinopathy had a mean baseline FPG level of 130 mg/dL and hemoglobin A1C level of 6.4%. Patients without retinopathy had a mean baseline FPG of 106 mg/dL and hemoglobin A1C level of 5.7%. Both differences were statistically significant (P < .001).

An FPG level of 108 mg/dL had a positive predictive value of retinopathy at 10 years of 8.4% and a level of 116 mg/dL had a predictive value of 14%.

A hemoglobin A1C level of 6% had a positive predictive value of 6% and a level of 6.5% had a predictive value of 14.8%, the authors reported.

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