Objective: The objective of the present study was to assess factors related to long-term changes in urinary albumin excretion (UAE) of nondiabetic microalbuminuric (n = 252) or proteinuric hypertensive individuals (n = 58) in a prospective follow-up.
Method: After enrollment, patients were placed on usual care including nonpharmacological treatment and/or treatment with an antihypertensive drug regime to achieve blood pressure < 135/85 mmHg. Periodic UAE measurements were performed until regression or significant reduction (defined when UAE dropped > 50% from the initial values, plus reduction of UAE to < 30 mg/24 h for microalbuminuric patients and < 300 mg/24 h for proteinuric patients).
Results: Among the microalbuminuric patients, 113 (44.8%) significantly reduced UAE after a mean follow-up of 18 months (range 12-69 months), 20.3/100 patients per year. Among the proteinuric patients, 29 (50%) significantly reduced UAE after a mean follow-up of 25 months (range 12-51 months), 20.2/100 patients per year. The baseline glomerular filtration rate, diastolic blood pressure and fasting glucose during follow-up were independent factors related to the regression or significant reduction in a Cox proportional hazard model. Regression of UAE was independently related to initial estimated glomerular filtration rate < or = 60 ml/min per 1.73 m (hazard ratio, 0.57; 95% confidence interval, 0.38-0.86; P = 0.001) and DBP > or = 90 mmHg achieved during the follow-up (hazard ratio, 0.57; 95% confidence interval, 0.38-0.86; P = 0.001), even when adjusted for age, gender, body mass index, fasting glucose, presence of treatment at the beginning of the study and treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers during the follow-up.
Conclusions: The reduction of urinary albumin excretion was linked to the preserved glomerular filtration rate and to adequate blood pressure control.