Blood pressure reduction associated with preservation of renal function in hypertensive patients with IgA nephropathy: a 3-year follow-up.

BACKGROUND: The relative importance of hypertension in the progression of renal failure is well understood. Recently, several studies have provided evidence that antihypertensive therapy enhances renal survival. However, the specific antihypertensive drug regimens that are most effective in generating such long-term effects remain controversial. PATIENTS AND METHODS: Forty-nine hypertensive IgA nephropathy (IgAN) patients (39 +/- 7 years old, serum creatinine 1.1 +/- 0.2 mg/dl) with proteinuria received antihypertensive therapy with angiotensin-converting enzyme inhibitors (ACEi: 2.5-10 mg of benazapril daily) and calcium channel blockers (CCBs: 2.5-10 mg amlodipine daily) for 3 years. The patients' blood pressures in group one were controlled below 140/85 mmHg by increases in their first drug dose or by addition of the second drug in group 1. Blood pressures for patients in group 2 were controlled using the same two options, except to levels below 130/70 mmHg. Patients within the two groups were selected and controlled with regard to sex, age, and serum creatinine. The renal protective effects of each protocol were evaluated in terms of reductions in creatinine clearance. After 3 years of the above outlined blood pressure control regimens, the reductions in creatinine clearance were compared. RESULTS: Creatinine clearances decreased in group 1 patients (from 85.7 +/- 2.4 ml/min to 72.9 +/- 2.4 ml/min, p < 0.05). On the other hand, creatinine clearance remained essentially unchanged for patients in group 2 (from 87.2 +/-4.7 ml/min to 85.9 +/- 5.9 ml/min). Although creatinine clearance in both groups was almost the same at the start of study, there was a significant difference between them by the conclusion of the study (p < 0.05). Proteinuria and hematuria did not change significantly throughout the study and there were no significant differences in these respects between these two corresponding groups. There were no significant differences between the groups with reference to side-effects or complications. CONCLUSION: These data provide evidence that reducing blood pressure has protective renal effects in cases of mild renal insufficiency with hypertension in IgA nephropathy.