Medline ® Abstracts for References 68,69

BACKGROUND: Stratum 2 of the Ramipril Efficacy in Nephropathy (REIN) study has already shown that in patients with chronic nephropathies and proteinuria of 3 g or more per 24 h, angiotensin-converting enzyme (ACE) inhibition reduced the rate of decline in glomerular filtration and halved the combined risk of doubling of serum creatinine or end-stage renal failure (ESRF) found in controls on placebo plus conventional antihypertensives. In REIN stratum 1, reported here, 24 h proteinuria was 1 g or more but less than 3 g per 24 h.

METHODS: In stratum 1 of this double-blind trial 186 patients were randomised to a ramipril or a control (placebo plus conventional antihypertensive therapy) group targeted at achieving a diastolic blood pressure of less than 90 mm Hg. The primary endpoints were change in glomerular filtration rate (GFR) and time to ESRF or overt proteinuria (>or =53 g/24 h). Median follow-up was 31 months.

FINDINGS: The decline in GFR per month was not significantly different (ramipril 0.26 [SE 0.05]mL per min per 1.73m2, control 0.29 [0.06]). Progression to ESRF was significantly less common in the ramipril group (9/99 vs 18/87) for a relative risk (RR) of 2.72 (95% CI 1.22-6.08); so was progression to overt proteinuria (15/99 vs 27/87, RR 2.40 [1.27-4.52]). Patients with a baseline GFR of 45 mL/min/1.73 m2 or less and proteinuria of 1.5 g/24 h or more had more rapid progression and gained the most from ramipril treatment. Proteinuria decreased by 13% in the ramipril group and increased by 15% in the controls. Cardiovascular events were similar. As expected, the rate of decline in GFR and the frequency of ESRF were much lower in stratum 1 than they had been in stratum 2.

INTERPRETATION: In non-diabetic nephropathies, ACE inhibition confers renoprotection even to patients with non-nephrotic proteinuria.

In this post hoc, secondary analysis of the Ramipril Efficacy In Nephropathy (REIN) trial, an angiotensin-converting enzyme (ACE) inhibition risk/benefit profile was assessed in 322 patients with nondiabetic, proteinuric chronic nephropathies and different degrees of renal insufficiency. The rate of GFR decline (Delta GFR) and the incidence of end-stage renal disease (ESRD) during ramipril or non-ACE inhibitor treatment were compared within three tertiles of basal GFR. Delta GFR was comparable in the three tertiles, whereas the incidence of ESRD was higher in the lowest tertile than in the middle and highest tertiles. Ramipril decreased Delta GFR by 22%, 22%, and 35% and the incidence of ESRD by 33% (P<0.05), 37%, and 100% (P<0.01) in the lowest, middle, and highest tertiles, respectively. Delta GFR reduction was predicted by basal systolic (P<0.0001), diastolic (P = 0.02), and mean (P<0.001) BP and proteinuria (P<0.0001) but not by basal GFR (P = 0.12). ESRD risk reduction was predicted by basal proteinuria (P<0.01) and GFR (P<0.0001) and was strongly dependent on treatment duration (P<0.0001). Adverse events were comparable among the three tertiles and within each tertile in the two treatment groups. Thus, disease progression and response to ACE inhibition do not depend on severity of renal insufficiency. The risk of ESRD and the absolute number of events saved by ACE inhibition is highest in patients with the lowest GFR. However, renoprotection is maximized when ACE inhibition is started earlier and when long-lasting treatment may result in GFR stabilization and definitive prevention of ESRD.