FACTORS INFLUENCING THE ESTIMATION OF THE ALBUMIN EXCRETION RATE IN SUBJECTS WITH DIABETES-MELLITUS

Objective: To evaluate alternative methods of calculating the albumin excretion rate (AER) in the absence of complete and accurate patient d ocumentation, since microalbuminuria in patients with diabetes mellitu s is associated with serious complications and since patients often ma ke errors in recording the volume and timing of urine collection, maki ng AER calculations inaccurate. Design: Prospective study. Setting: Re cruitment sites, including all native reserves, across southern Albert a. Participants: Population-based group of 1286 subjects with diabetes mellitus participating in the Southern Alberta Study of Diabetic Reti nopathy. Interventions: Timed AERs were measured in the subjects; urin ary albumin concentration was measured by radioimmunoassay. Outcome me asures: A formula for the prediction of AER was based on the clinical data from the subjects. Several factors were considered in developing the formula: insulin-using status, weight, sex and urine and serum cre atinine concentrations. Results: A mathematical model for estimation o f the AER was developed; incorporation of insulin use, sex and weight provides a more accurate estimate of AER. According to this model, wom en typically appear to have a lower AER than men and heavier people ap pear to have a higher AER than people with lower body weight. Conclusi ons: The use of mathematical formulae to calculate the AER provides an accurate estimate of the AER, particularly when data related to the v olume and timing of urine collection are missing. These formulae will be valuable in large epidemiologic screening programs.