Diabetic macular edema and its relationship to renal microangiopathy: a sample of Type I diabetes mellitus patients in a 15-year follow-up study

Abstract 

Purpose

In the present study, our objective was to determine the epidemiological risk factors for the development of diabetic macular edema, especially attendant on renal diabetic lesion (microalbuminuria or overt nephropathy) in 112 Type I diabetic patients after 15 years.

Methods

This is a 15-year follow-up study of a cohort of 112 consecutive Type I (insulin-dependent) diabetes mellitus patients without diabetic retinopathy or nephropathy who were enrolled in 1990. We studied the incidence of diabetic macular edema and its risk factors. The epidemiological risk factors included in the study were as follows: gender, diabetes duration, glycated hemoglobin (HbA_1c) levels, arterial hypertension, macroangiopathy, triglyceride levels, fractions of cholesterol [high-density lipoprotein cholesterol and low-density lipoprotein (LDL) cholesterol], and cigarette smoking.

Results

The incidence of diabetic macular edema after 15 years was as follows: the focal form of diabetic macular edema was present in 13 (11.6%) patients and the diffuse form of macular edema was present in 10 (8.9%) patients, among 23 (20.5%) patients. The following factors were significant in the development of diabetic macular edema: high levels of LDL-cholesterol (P=.013), high levels (>7.5%) of HbA_1c (P=.021), the presence of macroangiopathy (P=.022), the severity of diabetic retinopathy (P=.029), the presence of arterial hypertension (P=.037), and the presence of overt nephropathy (P=.047). Microalbuminuria was not significant in logistic regression (P=.587), and cigarette smoking was not significant (P=.976). The relationship between diabetic macular edema and duration of diabetes presented two peaks of incidence: first in patients with 15–20 years' duration of diabetes mellitus, and second in patients with >35 years' duration.

Conclusions

In summary, our data suggest that better control of glycemia, LDL-cholesterol levels, and blood pressure in Type I diabetes mellitus patients may be beneficial in reducing the incidence of diabetic macular edema. Finally, our data validate the current guidelines for ophthalmologic care for the detection of diabetic macular edema over the long-term course of diabetes.

Keywords: Diabetic macular edema, Diabetic retinopathy, Diabetic nephropathy, Microalbuminuria, Diabetic epidemiology, Optical coherence tomography