Renin-angiotensin-aldosterone system blockade and urinary albumin excretion in community-based patients with Type 2 diabetes: The Fremantle Diabetes Study

Abstract

To determine whether the reduction in urinary albumin excretion through renin-angiotensin-aldosterone system blockade found in intervention trials extends to community-based patients with Type 2 diabetes. We analysed data from 302 participants in the longitudinal observational Fremantle Diabetes Study who commenced angiotensin-converting enzyme inhibitor or angiotensin receptor blocker therapy during follow-up and who had an annual assessment on either side of this therapeutic change. At baseline, the patients had a mean age of 63.8 years, a median diabetes duration of 4 years, a median HbA(1c) of 7.6% (60 mmol/mol) and a geometric mean (sd range) urinary albumin:creatinine ratio of 3.3 mg/mmol (0.8-13.1 mg/mmol). The percentages with normo-, micro- and macroalbuminuria were 49.0, 38.4 and 12.6%, respectively. During 6.1 ± 1.7 years of follow-up, initiation of renin-angiotensin-aldosterone system blockade was associated with a larger geometric mean (sd range) absolute albumin:creatinine ratio reduction in the patients with macroalbuminuria compared with those who had either normo- or microalbuminuria [-40.9 (-825.7 to 159.9) mg/mmol) vs. 1.7 (-1.6 to 20.0) mg/mmol and -0.5 (-23.0 to 39.5) mg/mmol, respectively; P < 0.001]. These changes remained significant after adjustment for changes in blood pressure and other potentially confounding variables, including drug dose and angiotensin-converting enzyme genotype. The post-treatment median albumin:creatinine ratios were 35.4 and 27.4% lower than before treatment in those with micro- or macroalbuminuria, respectively. Usual-care initiation of renin-angiotensin-aldosterone system blockade confers a quantitatively similar renal benefit to that in intervention trials in Type 2 diabetes.