97th DOG Annual Meeting 1999

P549

THE DIABETIC RETINOPATHY IN CORRELATION TO DIABETES TREATMENT IN TYPE 1 DIABETICS

C. Clanget, M. Frank, M. T. Grauer, K. W. Ruprecht

Since the conclusion of the Diabetes Control and Complications Trial (DCCT), the correlation between blood glucose adjustment and diabetic retinopathy is generally acknowledged. Using multi-variance analysis, we studied, which HbA1c range offers the greatest benefit for the patient, taking into account risk of hypoglycemia. In addition, the importance of other parameters and their effects on each other were analyzed.

Methods: 61 type 1 diabetics were observed over a mean time of 3.5 years. As suspected influencing factors, HbA1c, duration of diabetes, age at onset of diabetes, blood pressure, serum lipids, BMI, cigarette smoking and insulin therapy were analyzed. Besides severity and course of retinopathy, creatinine, microalbuminuria, sensory nerve conduction velocity (NCV) and clinical symptoms of diabetic neuropathy were studied. In addition, light and severe hypoglycemias were recorded and correlated with the HbA1c levels.

Results: Duration of diabetes was associated significantly with retinopathy (unit-odds ratio 1.22; p=0.0002). Patients with HbA1c > 7% had a 3.52 times higher risk than patients with an HbA1c < 7% (p=0.026). The share of patients with hypertension was 34% in the group with retinopathy, compared with 14% in the group without retinopathy. No patient without retinopathy had diastolic blood pressure > 90mmHg. A sensory NCV < 50m/s was associated with a 19.7 times higher risk for retinopathy (p=0.007), significance remained when NCV was analyzed as continuous variable (p=0.023). We did not observe a correlation between HbA1c and the frequency of severe hypoglycemias (spearman-rank correlation coefficient 0.197; p=0.15).

Conclusions: Besides hyperglycemia, increased blood pressure, particularly increased diastolic pressure is a risk factor for retinopathy. Contrary to nephropathy, neuropathy is significantly associated with retinopathy. Contrary to the results of the DCCT, lower HbA1c levels < 7% were not associated with a higher frequency of hypoglycemia. Despite the clear significances of the described correlations, methodological questions have emerged that are worth discussing.

Universitäts-Augenklinik und Poliklinik, Kirrberger Str.1, 66421 Homburg (Saar)

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