Aims: There is paucity of data on the long-term variability of Albumin Excretion Rate (AER) in patients with type II diabetes. This study aimed to determine the variability of AER and factors that influence it, in type II diabetic patients.
Methods: Consecutive AER measurements from 1999-2012 of 497 type II diabetic patients were recorded in a cohort study. Coefficient of variation (CV) was used as a measure of intraindividual AER variability. The first three AER measurements were used to classify individuals into normo-, micro- and macroalbuminuria groups at baseline. Linear regression examined the effects of baseline demographic variables on the AER CV: AER group, HbA1c, age, gender, duration of diabetes, total cholesterol, HDL, systolic BP, BMI, ACEi/ARB use at baseline and smoking. A logarithmic transformation was applied to CV prior to analyses.
Results: The intraindividual variability in AER was compared between treated (ACEi/ARB use in 2000, n=312) and untreated(n=185) patients. The CV was higher in those treated than those untreated(p=0.003). There was no evidence of a relationship between the AER CV and baseline characteristics. Linear regression of log CV in treated and untreated groups and AER groups was used. After adjustment for AER groups, the difference in mean CV between the treated and untreated groups remained significant(p=0.013). After adjustment for ACEi/ARB use, the mean CV in the microalbuminuria group was 1.27 times that of the normoalbuminuria group, 1.15 times greater in macroalbuminuria compared to the normoalbuminuria, with no difference for micro- versus macroalbuminuria groups. Overall, p<0.001.
Conclusion: Patients with type II diabetes and micro- or macroalbuminuria have a greater AER CV than those with normoalbuminuria at baseline. There was a greater intraindividual CV in those treated with ACEi/ARB indicating greater changes in AER over time in these patients. These results emphasize the need for serial AER measurements in assessing AER trajectory.