Diabetic control and progression of retinopathy in elderly patients: five-year follow-up study.

OBJECTIVE

To assess whether control of diabetes mellitus is as important in the elderly as in young and middle-aged diabetic patients in terms of progression of retinopathy.

DESIGN

A 5-year longitudinal cohort study.

SETTING

Outpatient diabetic clinic.

PATIENTS

One hundred fourteen non-insulin-dependent diabetic patients (30 males, 84 females) > or = 60 years of age.

MEASUREMENTS

Retinopathy was checked at the beginning and end of the follow-up period. During the 5-year follow-up period, demographic variables, body mass index, HbA1c, blood pressure, and plasma lipids were monitored. Retinopathy was classified as follows: grade 0, no lesion; grade 1, non-proliferative retinopathy; grade 2, pre-proliferative retinopathy; grade 3, proliferative retinopathy. Progression of retinopathy during the 5-year follow-up was defined as an increase in its grade.

RESULTS

At the start of the study, 13% of the patients already had retinopathy, all of grade 1. The 5-year follow-up study showed that progression of retinopathy was 23.6% in all cases, 22.2% in those with grade 0 initially, and 33.3% in those with grade 1 initially. The progression rates of retinopathy as a function of the mean HbA1c during the follow-up were as follows: lower than 7%, 2%; 7-8%, 20%; 8-9%, 40%; more than 9%, 61%. Multiple logistic regression analysis showed that, of the parameters examined, only HbA1c was a significant risk factor for progression of retinopathy.

CONCLUSIONS

Control of diabetes mellitus is the most important factor associated with prevention of progression of retinopathy in elderly patients.