The Effect of Calcium Channel Blockers on Moderate or Severe Albuminuria in Diabetic, Hypertensive Patients

Inhibitors of the renin-angiotensin system are recommended for the management of albuminuria in patients with hypertension and diabetes mellitus, but there is little consensus about alternative therapies. Calcium channel blockers are recommended for the management of hypertension, but the data are controversial regarding their role in patients with albuminuria. This review was designed to assess the efficacy of calcium channel blockers compared with inhibitors of the renin-angiotensin system in decreasing albuminuria in diabetic, hypertensive patients with nephropathy. We searched MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov for records that compared calcium channel blockers to inhibitors of the renin-angiotensin system and reported pre- and postintervention albuminuria measurements. Two reviewers independently screened abstracts for randomized, controlled trials in adults. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to select 29 trials from 855 records. We synthesized the data through a random-effects model. We analyzed data from 2113 trial participants with hypertension and diabetes mellitus who had the equivalent of ≥30 mg/day of urinary albumin excretion. Inhibitors of the renin-angiotensin system were more effective than calcium channel blockers in decreasing albuminuria (standardized difference in means −0.442; confidence interval, −0.660 to −0.225; P < .001). This finding was independent of the blood pressure response to treatment. There was no difference between the 2 drug classes regarding markers of renal function. Inhibitors of the renin-angiotensin system are superior to calcium channel blockers for the reduction of albuminuria in nephropathy due to hypertension and diabetes mellitus. The net clinical benefit, however, is small.