The natural course of microalbuminuria in African Americans (AA) with type 2 diabetes is not well established.

Longitudinal analysis of 186 African Americans with type 2 diabetes enrolled in Project Sugar, a randomized controlled trial of primary care-based interventions to improve diabetes control.

Mean age was 59.4 years and 85% were female. Mean estimated glomerular filtration rate and urinary albumin-to-creatinine ratio were 75.90 mL/min/1.73 m² and 1.62, respectively. Thirty-nine patients had macroalbuminuria and significantly higher systolic blood pressure compared with those with microalbuminuria (P=.01). Sixty patients had microalbuminuria, 19 progressed to macroalbuminuria, and none regressed. Progression was associated significantly with systolic blood pressure ≥115 mm Hg and requirement for blood pressure medication in the univariate model. In the multivariate model, the degree of albumin-to-creatinine ratio (odds ratio 35.51, 95% confidence interval, 2.21-571.65) and need for blood pressure medication (odds ratio 8.96, 95% confidence interval, 1.35-59.70) were independently associated with progression. No association was observed with the use of specific antihypertensive agent.

This study suggests that African Americans with type 2 diabetes and microalbuminuria experience irreversible disease that not infrequently progresses to overt proteinuria. The degree of microalbuminuria and blood pressure are key determinants in this process and should be primary targets in treating this population regardless of the antihypertensive class used.