Medline ® Abstracts for References 65-68,70,71

BACKGROUND: In diabetic nephropathy, angiotensin-converting-enzyme (ACE) inhibitors have a greater effect than other antihypertensive drugs on proteinuria and the progressive decline in glomerular filtration rate (GFR). Whether this difference applies to progression of nondiabetic proteinuric nephropathies is not clear. The Ramipril Efficacy in Nephropathy study of chronic nondiabetic nephropathies aimed to address whether glomerular protein traffic influences renal-disease progression, and whether an ACE inhibitor was superior to conventional treatment, with the same blood-pressure control, in reducing proteinuria, limiting GFR decline, and preventing endstage renal disease.

METHODS: In this prospective double-blind trial, 352 patients were classified according to baseline proteinuria (stratum 1: 1-3 g/24 h; stratum 2:>or = 3 g/24 h), and randomly assigned ramipril or placebo plus conventional antihypertensive therapy targeted at achieving diastolic blood pressure under 90 mm Hg. The primary endpoint was the rate of GFR decline. Analysis was by intention to treat.

FINDINGS: At the second planned interim analysis, the difference in declinein GFR between the ramipril and placebo groups in stratum 2 was highly significant (p = 0.001). The Independent Adjudicating Panel therefore decided to open the randomisation code and do the final analysis in this stratum (stratum 1 continued in the trial). Data (at least three GFR measurements including baseline) were available for 56 ramipril-assigned patients and 61 placebo-assigned patients. The decline in GFR per month was significantly lower in the ramipril group than the placebo group (0.53 [0.08]vs 0.88 [0.13]mL/min, p = 0.03). Among the ramipril-assigned patients, percentage reduction in proteinuria was inversely correlated with decline in GFR (p = 0.035) and predicted the reduction in risk of doubling of baseline creatinine or endstage renal failure (18 ramipril vs 40 placebo, p = 0.04). The risk of progression was still significantly reduced after adjustment for changes in systolic (p = 0.04) and diastolic (p = 0.04) blood pressure, but not after adjustment for changes in proteinuria. Blood-pressure control and the overall number of cardiovascular events were similar in the two treatment groups.

INTERPRETATION: In chronic nephropathies with proteinuria of 3 g or more per 24 h, ramipril safely reduces proteinuria and the rate of GFR decline to an extent that seems to exceed the reduction expected for the degree of blood-pressure lowering.

BACKGROUND: The Ramipril Efficacy In Nephropathy (REIN) study found that in patients with chronic nephropathies and proteinuria of 3 g or more per 24 h, ramipril safely reduced the rate of decline of the glomerular filtration rate (GFR) and halved the combined risk of doubling of serum creatinine or end-stage renal failure (ESRF), as compared with placebo plus conventional antihypertensive drugs at the same level of blood pressure control. At the end of the core study patients continued on or shifted to ramipril and were formally enrolled into the REIN follow-up study.

METHODS: 97 patients entered the follow-up study. Patients originally randomised to ramipril continued with the same daily dose (n=51), whereas those originally on placebo plus conventional antihypertensive drugs switched to ramipril after the first visit of the follow-up study (n=46). Ramipril (1.25 to 5.00 mg/day) and conventional antihypertensive therapy were targeted at achieving diastolic blood pressure under 90 mm Hg. The main efficacy variables were GFR decline and ESRF (need for dialysis). Analysis was by intention to treat.

FINDINGS: During the follow-up study the mean rate of GFR decline per month decreased from 0.44 (SD 0.54) mL/min per 1.73 m2 in the core study to 0.10 (0.50) mL/min per 1.73 m2 in patients originally randomised to ramipril (p=0.017), and from 0.81 (1.12) to 0.14 (0.87) mL/min per 1.73 m2 in those originally randomised to placebo plus conventional antihypertensive therapy (p=0.017). At the final visit, mean absolute GFR values were 12 mL/min per 1.73 m2 higher (33% better) in patients randomised to ramipril than in those assigned placebo (n=26 and 17, respectively: 35.5 [19.0]vs 23.8 [9.4]mL/min per 1.73 m2, p=0.01). 19 of the patients originally on ramipril versus 35 switched from placebo to ramipril progressed to ESRF (p=0.027) during the whole observation period; of these, six (8%) versus 14 (16%) reached that endpoint during the follow-up study; and the risk ratios were 1.86 (95% CI 1.07-3.26) over the whole observation period and 2.95 (1.13-7.68) during follow-up. Beyond follow-up at month 36, the incidence of ESRF was zero in patients originally randomised to ramipril but 30% in patients on placebo plus conventional antihypertensive therapy.

INTERPRETATION: In patients with chronic nephropathy and high risk of rapid progression to ESRF, ramipril reversed the tendency of GFR to decline with time. Moreover, a treatment period of sufficient duration (>or =36 months) eliminated the need for dialysis. Even patients previously treated with antihypertensive drugs other than angiotensin-converting-enzyme inhibitors benefited from shifting to ramipril.

The Ramipril Efficacy in Nephropathy Core and Follow-Up Study found that>or =36 mo of continued ramipril therapy decreased substantially the risk of end-stage renal failure (ESRF) in patients with chronic nephropathies and a urinary protein excretion rate>or =3 g/24 h. This study investigates the time-dependent changes in GFR in these patients and in control subjects who were randomized to conventional therapy during the Core period and switched to ramipril during the Follow-Up study. Analyses included 150 patients (continued ramipril: n = 74; switched to ramipril: n = 76) who had at least three GFR measurements (including baseline) during the whole observation period and a subgroup of 43 patients (continued ramipril: n = 26; switched to ramipril: n = 17) who had at least six GFR measurements, including at least three on the Core and at least three on the Follow-Up study. Ramipril (1.25 to 5 mg/d) and conventional therapy were targeted at achieving a diastolic BP below 90 mm Hg. The main efficacy variables were GFR and ESRF (need for dialysis). Analysis was by intention to treat. Throughout the study, the mean +/- SEM rate of GFR decline (deltaGFR) was significantly lowerin patients continued on ramipril compared to those switched to ramipril (0.51+/-0.09 versus 0.76+/-0.10 ml/min per 1.73 m2 per mo, P<0.03). In patients on continued ramipril who had at least six GFR measured--but not in control subjects--deltaGFR progressively improved with time and, in the cohort with the longest follow-up, decreased from (in ml/min per 1.73 m2 per mo): 0.16+/-0.12 (at 18 mo) to 0.10+/-0.05 (at 60 mo). This rate was about 10-fold slower compared to patients on conventional therapy during the REIN Core study. Analyses of the individual slopes found that at the end of the follow-up, 10 of 26 patients on continued ramipril therapy had a positive deltaGFR and another 10 patients had an improvement of deltaGFR while on ramipril therapy. DeltaGFR significantly improved in parallel with a significant reduction in proteinuria. Changes in deltaGFR (P = 0.0001) and proteinuria (P = 0.04) were significantly different in the two groups. Baseline characteristics and changes in systolic and diastolic BP and 24-h urine urea and sodium excretion were comparable. The present results offer evidence that in chronic nephropathies, the tendency of GFR to decline with time can be effectively halted, even in patients with remarkably severe disease.

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.

The Ramipril Efficacy in Nephropathy (REIN) study found that angiotensin-converting enzyme (ACE) inhibitors effectively decreased proteinuria, glomerular filtration rate (GFR) decline (DeltaGFR), and incidence of end-stage renal disease (ESRD) in patients with proteinuric chronic nephropathies. In this study, we prospectively investigated the main clinical determinants of progression and response to treatment in the 352 patients enrolled into the REIN study. Mean DeltaGFR (0.56 +/- 0.05 [SEM]versus 0.21 +/- 0.05 mL/min/1.73 m(2)/mo; P = 0.0001) and incidence of ESRD (30% and 10%; P = 0.0001) were more than twice that in patients with proteinuria of 2 g/24 h or greater of protein compared with those with protein less than 2 g/24 h (relative risk [RR], 4.07; 95% confidence interval [CI], 2.20 to 7.52), as well as in patients with hypertension compared with normotension (mean DeltaGFR, 0.48 +/- 0. 05 versus 0.22 +/- 0.05 mL/min/1.73 m(2)/mon; P = 0.0006; ESRD, 25% versus 10%; P = 0.004; RR, 3.18; 95% CI, 1.38 to 7.32). Hypertension at study entry (P = 0.038), greater mean blood pressure on follow-up (P = 0.002), and urinary protein excretion rate (P = 0.0001) were independent predictors of faster DeltaGFR. DeltaGFR was approximately twofold faster in patients with type 2 diabetes than in those with primary glomerular disease (P = 0.002; including immunoglobulin A [IgA]nephropathy, P = 0.009); nephrosclerosis (P = 0.03), adult polycystic kidney disease (APKD), or chronic interstitial nephritis (P = 0.006). Diabetes at study entry (P = 0. 02) and greater mean blood pressure (P = 0.0001) and urinary protein excretion rate (P = 0.0001) on follow-up were independent predictors of faster DeltaGFR. After correction for baseline covariates, diabetes was also associated with an increased risk for progression to ESRD (RR, 2.39; 95% CI, 1.01 to 5.68; P<0.05). At multivariate analyses, ramipril significantly decreased DeltaGFR (regression coefficient,-0.23 +/- 0.11 [SEM]; P = 0.036) and ESRD (RR, 2.08; 95% CI, 1.21 to 3.57; P = 0.008) in patients with baseline proteinuria of 2 g/24 h or greater of protein, and the renoprotective effect increased for increasing levels of proteinuria. Ramipril decreased DeltaGFR to a similar extent in normotensive and hypertensive patients (-0.14 +/- 0.11 versus -0.14 +/- 0.09) and significantly limited ESRD in hypertensive patients (RR, 2.03; 95% CI, 1.26 to 3. 26; P = 0.004). DeltaGFR was decreased by 42% in primary glomerular disease (P = 0.017), by 35% in IgA nephropathy, and by 37% in nephrosclerosis, but was not improved in type 2 diabetes, APKD, or interstitial nephritis. At multivariate analyses, ramipril significantly slowed DeltaGFR (-0.24 +/-0.08; P = 0.004) and progression to ESRD (RR, 2.32; 95% CI, 1.36 to 3.96; P = 0.002) in patients without diabetes, but not in patients with diabetes, who tended to have a faster DeltaGFR (+0.62 +/- 0.44) on ramipril therapy. In summary, patients with proteinuria of 2 g/24 h or greater of protein, preexisting hypertension, or type 2 diabetes were faster progressors. Greater blood pressure and degree of proteinuria were the strongest determinants of faster GFR decline. The renoprotective effect of ramipril was similar in patients with normotension and hypertension. Hypertensive patients and those with proteinuria of 2 g/24 h or greater of protein, primary glomerular disease, or nephrosclerosis gained the most from ACE inhibitor treatment. During the study period, those with proteinuria less than 2 g/24 h of protein, type 2 diabetes, or polycystic kidney disease did not benefit by treatment to an appreciable extent.

Angiotensin-converting enzyme inhibitors and angiotensin II-receptor antagonists are recommended for patients with chronic kidney disease because these drugs can slow disease progression. Older adults account for a large and growing number of patients with chronic kidney disease. The authors evaluated the relevance to adults older than 70 years of the evidence base for major U.S. practice guidelines for the use of these agents in chronic kidney disease. The authors first examined the representation of older adults in randomized trials that underpin these guidelines, then compared the characteristics of participants in these trials with those of a representative sample of older adults with chronic kidney disease in the general population. The authors found that current guidelines for the use of angiotensin-converting enzyme inhibitors and angiotensin II-receptor antagonists in chronic kidney disease are based on evidence with limited relevance to most persons older than 70 years with this condition.