Objective: To evaluate if urinary albumin excretion rate (UAER) is independently related to subclinical autonomic neuropathy in type 2 diabetes.
Design: A controlled cross-sectional study.
Setting: Primary health care centre.
Subjects: Consecutive recently diagnosed (< 1 year) type 2 diabetic patients (group A, n = 150) and patients with long-standing (median 11 years) type 2 diabetes (group B, n = 146) chosen at random. A nondiabetic control group (group C, n = 150) matched for age and gender to group A.
Main outcome measures: Neuropathy by cardiovascular reflex tests and UAER by nephelometry.
Methods: Univariate statistics in group A + B (t-test chi 2- or McNemars test) with Valsalva and breathing ratios as categorical grouping variables and the independent variables gender, smoking, systolic and diastolic blood pressure, fasting serum cholesterol, HDL cholesterol, triglycerides, haemoglobin A1c, glucagon stimulated C-peptide, fasting and postload 1 and 2 h blood glucose and serum insulin, UAER, coronary heart disease and congestive heart failure. Logistic regression analyses in group A + B with Valsalva and breathing ratios as dependent categorical variables and age, systolic blood pressure, congestive heart failure, coronary heart disease, fasting blood glucose, serum triglycerides and UAER as independent variables.
Results: Compared to nondiabetic subjects the diabetic patients of both groups were at increased risk of neuropathy as judged by the Valsalva ratio (P < 0.01). In known diabetic patients with a UAER > or = 30 mg 24-1 h neuropathy was more common than amongst their normoalbuminuric counterparts (Valsalva test P = 0.007, breathing test P = 0.02). In logistic regression analysis UAER independently explained abnormal Valsalva (P = 0.015) and breathing tests (P = 0.04) in the group A + B.
Conclusions: UAER is independently related to subclinical autonomic neuropathy in type 2 diabetes.