The response to antihypertensive therapy is dependent on renal structural changes. A 5-year prospective study of renal biopsy in type 2 diabetic patients with micro-macroalbuminuria

Abstract 

A substantial fraction of patients with diabetes mellitus develop end-stage renal disease. We wanted to study the influence of renal structural changes on the response to treatment of the systemic blood pressure (BP) in type 2 diabetic patients with micro- or macroalbuminuria.

Methods

A 5-year observational prospective study of 40 type 2 diabetic patients. Renal biopsy was performed on the indication micro-macroalbuminuria. Twenty-four-hour ambulatory BP and urine sampling were performed yearly. The goal for treatment was a nightly systolic BP below 140 mmHg. Glomerular filtration rate was examined early with plasma clearance of iohexol.

Results

The nightly systolic BP goal <140 mmHg was achieved in 23 of 40 patients. The nightly systolic BP at start of study was correlated to the mean level of nightly systolic BP during the observation period. The glomerular basement membrane (GBM) thickness (BMT) was of prognostic significance for achieving the goal for antihypertensive treatment. Of the 12 patients with BMT below the median of 478 nm, 9 (75%) achieved the goal, while only 5 of 12 (42%) with BMT above 478 nm achieved a nightly systolic BP <140 mmHg. Also, the degree of interstitial fibrosis correlated to the nightly systolic BP.

Conclusion

A thick basement membrane and the degree of interstitial fibrosis were associated with a lower number of patients achieving the goal of a nightly systolic BP <140 mmHg.

Keywords: Basement membrane, Systolic BP, Micro-macroalbuminuria, Ambulatory blood pressure, Diabetes mellitus