Risk Factors for Development of Diabetic Nephropathy and Retinopathy in Jewish IDDM Patients

Risk factors associated with diabetic microvascular complications, with special reference to ethnic origin, were looked for in 231 young Jewish insulin-dependent diabetes mellitus (IDDM) patients with duration of diabetes ≥10 yr. Median age at diagnosis of diabetes was 9.2 yr (range 0.04–26.2 yr), and median duration of the disease was 15.3 yr (range 10.0–37.2 yr). Sixty-three percent of the patients were Ashkenazi Jews, and 37% were non-Ashkenazi Jews. HbA₁ was evaluated every 3 mo in the last 10 yr of follow-up, and albumin excretion rate was tested in three 24-h urine collections. Direct and indirect ophthalmoscopy was performed every year since diagnosis of diabetes, and if retinal pathology was suspected, color photographs were taken. Microalbuminuria was detected in 31% and macroalbuminuria in 7% of the patients. Nonproliferative and proliferative retinopathy was found in 44 and 12% of the patients, respectively. On logistic regression analysis, two variables were significantly and independently associated with diabetic nephropathy—non-Ashkenazi origin and mean HbA₁ values over the first 5 of 10 yr of follow-up. Variables significantly and independently related to diabetic retinopathy were non-Ashkenazi origin, mean HbA₁ values over the last 10 yr of follow-up, and duration of diabetes. Because non-Ashkenazi Jews in Israel are of lower socioeconomic status than Ashkenazi Jews, we stratified our patients according to their socioeconomic parameters, median HbA₁ values, and duration of diabetes. Non-Ashkenazi patients were at a higher risk to develop complications in all strata. We further stratified patients into four quartiles according to mean HbA₁ values; there was a steep increase in the risk to develop macroalbuminuria in the 4th quartile of HbA₁ (odds ratio [OR] 4.3 vs. 1.2 in the 3rd quartile) and proliferative retinopathy (OR 13.0 in the 4th quartile of HbA, vs. 2.8 in the 3rd quartile). We conclude that non-Ashkenazi Jewish IDDM patients are at significant risk to develop microvascular complications, independent of their glycemic control, duration of diabetes, and socioeconomic status. Careful follow-up and special efforts toward improving glycemic control should be focused on high-risk subgroups of patients.