Preventing microalbuminuria with benazepril, valsartan, and benazepril–valsartan combination therapy in diabetic patients with high-normal albuminuria: A prospective, randomized, open-label, blinded endpoint (PROBE) study

Background Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) prevent microalbuminuria in normoalbuminuric type 2 diabetic patients. We assessed whether combined therapy with the 2 medications may prevent microalbuminuria better than ACE inhibitor or ARB monotherapy. Methods and findings VARIETY was a prospective, randomized, open-label, blinded endpoint (PROBE) trial evaluating whether, at similar blood pressure (BP) control, combined therapy with benazepril (10 mg/day) and valsartan (160 mg/day) would prevent microalbuminuria more effectively than benazepril (20 mg/day) or valsartan (320 mg/day) monotherapy in 612 type 2 diabetic patients with high-normal albuminuria included between July 2007 and April 2013 by the Istituto di Ricerche Farmacologiche Mario Negri IRCCS and 8 diabetology or nephrology units in Italy. Time to progression to microalbuminuria was the primary outcome. Analyses were intention to treat. Baseline characteristics were similar among groups. During a median [interquartile range, IQR] follow-up of 66 [42 to 83] months, 53 patients (27.0%) on combination therapy, 57 (28.1%) on benazepril, and 64 (31.8%) on valsartan reached microalbuminuria. Using an accelerated failure time model, the estimated acceleration factors were 1.410 (95% CI: 0.806 to 2.467, P = 0.229) for benazepril compared to combination therapy, 0.799 (95% CI: 0.422 to 1.514, P = 0.492) for benazepril compared to valsartan, and 1.665 (95% CI: 1.007 to 2.746, P = 0.047) for valsartan compared to combination therapy. Between-group differences in estimated acceleration factors were nonsignificant after adjustment for predefined confounders. BP control was similar across groups. All treatments were safe and tolerated well, with a slight excess of hyperkalemia and hypotension in the combination therapy group. The main study limitation was the lower than expected albuminuria at inclusion. Conclusions Risk/benefit profile of study treatments was similar. Dual renin–angiotensin system (RAS) blockade is not recommended as compared to benazepril or valsartan monotherapy for prevention of microalbuminuria in normoalbuminuric type 2 diabetic patients. Trial registration EudraCT 2006-005954-62; ClinicalTrials.gov NCT00503152.
Piero Ruggenenti and co-workers study prevention of microalbuminuria in patients with type 2 diabetes.
Author summary Why was this study done? Renin–angiotensin system (RAS) blockade with angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) prevents the onset of microalbuminuria in patients with type 2 diabetes and normoalbuminuria. Some studies found that ACE inhibitor and ARB combination therapy reduced urinary albumin excretion (UAE) more effectively than ACE inhibitor or ARB monotherapy in type 2 diabetic patients with microalbuminuria or macroalbuminuria. Treatment effect was, however, associated with greater blood pressure (BP) reduction. Whether, at comparable BP control, dual RAS inhibition with an ACE inhibitor and an ARB could be more renoprotective than either monotherapy in diabetic patients with no evidence of kidney disease is unknown. What did the researchers do and find? In this prospective, randomized, open-label, blinded endpoint (PROBE) trial, we evaluated whether, at similar BP control, combination therapy with the ACE inhibitor benazepril and the ARB valsartan would reduce the incidence of microalbuminuria more effectively than benazepril or valsartan monotherapy in 612 patients with type 2 diabetes and high-normal albuminuria. Secondarily, we compared the effects of the 2 monotherapies on the primary prevention of microalbuminuria in this population. We found that during a median follow-up of 66 months, combined treatment with half of the standard manufacturer-recommended antihypertensive doses of benazepril and valsartan had no superior effect against progression to microalbuminuria as compared to monotherapy with full recommended doses of either benazepril or valsartan. The protective effects of benazepril and valsartan monotherapies against progression to microalbuminuria were also similar. All treatments were safe and well tolerated, with a slight excess of hyperkalemia and hypotension episodes in the combination therapy group. What do these findings mean? Dual RAS blockade should not be preferred to ACE inhibitor or ARB monotherapy for the primary prevention of microalbuminuria in patients with type 2 diabetes and normoalbuminuria. Recent studies showing that sodium–glucose co-transporter 2 (SGLT2) inhibitors may afford substantial nephro- and cardioprotection to patients with type 2 diabetes and varying degrees of albuminuria might pave the way to novel prevention strategies based upon the integrated use of these novel medications with an ACE inhibitor or an ARB, but not with their combination.