Urinary Albumin Excretion as a Predictor of Diabetic Retinopathy, Neuropathy, and Cardiovascular Disease in NIDDM

OBJECTIVE The relationship between urinary albumin excretion (UAE) and diabetic complications in NIDDM has not been studied in a large American population. The demonstrated relationship between increased UAE and the development of retinopathy, nephropathy, and neuropathy in IDDM makes this an important issue to also be studied in NIDDM patients. RESEARCH DESIGN AND METHODS A large population study of 947 NIDDM patients living predominantly in a metropolitan area was undertaken. Three categories of UAE, namely, normal albuminuria (< 20 μg/min), microalbuminuria (20–200 μg/min), and overt albuminuria (>200 μg/min) were compared with 1) retinopathy as assessed by stereoscopic fundus photographs; 2) cardiovascular disease as assessed by a history of cardiac disease or stroke; ischemic changes on exercise treadmill testing; Q wave myocardial infarction; Estes, Sokolow, or Cornell criteria for left ventricular hypertrophy; positive Rose questionnaire for angina; and an abnormal Doppler exam for peripheral vascular disease; and 3) neuropathy as assessed by neurological symptom and disability scores, autonomic function testing, and quantitative sensory exams involving thermal and vibratory sensation. Selected patient characteristics were then evaluated to determine their effects on the presence of diabetic complications using univariate analyses. Multiple logistic regression analyses were then performed to determine the independent effect of UAE on these diabetic complications. RESULTS χ2 analyses revealed that UAE was significantly associated with the presence of retinopathy (P < 0.001), neuropathy (P < 0.001), and cardiovascular disease (P < 0.001). In the multiple logistic regression analyses, UAE had strong independent associations with retinopathy, neuropathy, and cardiovascular disease. CONCLUSIONS Thus, increasing UAE in this large NIDDM population in the U.S. was associated with an increased prevalence of diabetic retinopathy, neuropathy, and cardiovascular disease. This suggests that UAE may be more than an indicator of renal disease in NIDDM patients and, in fact, may reflect a state of generalized vascular damage occurring throughout the body. Prospective studies in NIDDM patients are needed to determine the predictive effect of UAE and the effect of decreasing UAE on future diabetic micro- and macrovascular complications.