A Cochrane review included 60 studies with a total of 3 802 subjects; 29 studies (n=2262) compared calcium channel blockers (CCB) to placebo/no treatment; 10 studies (n=445) compared angiotensin converting enzyme inhibitors (ACEi) to placebo/no treatment, and 7 studies (n=405) compared CCB to ACEi. Other drug comparisons were in small numbers of participants and studies.
CCB compared to placebo/no treatment (plus additional agents in either arm as required) reduced graft loss (RR 0.75, 95% CI 0.57 to 0.99; 17 studies, n=1255) and improved glomerular filtration rate (GFR), (MD, 4.45 mL/min, 95% CI 2.22 to 6.68; 16 studies, n=1119). There was no effect of CCB on risk of death at 12 months (RR 0.82, 95% CI 0.37 to 1.82; 12 studies, n=792).
Data on ACEi versus placebo/no treatment were inconclusive for GFR (MD -8.07 mL/min, 95% CI -18.57 to 2.43), and variable for graft loss, precluding meta-analysis.
In direct comparison with CCB, ACEi decreased GFR (MD -11.48 mL/min, 95% CI -5.75 to -7.21; 6 studies, n=296), proteinuria (MD -0.28 g/24 h, 95% CI -0.47 to -0.10; 2 studies, n=147), haemoglobin (MD -12.96 g/L, 95% CI -5.72 to -10.21; 5 studies, n=332) and increased hyperkalaemia (RR 3.74, 95% CI 1.89 to 7.43; 3 studies, n=211). Graft loss data were inconclusive (RR 7.37, 95% CI 0.39 to 140.35; 1 study, n=152). Death was reported in two studies with no difference in risk (RR 4.03, 95% CI 0.45 to 35.82; 2 studies, n=221).
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment and blinding) and by imprecise results (limited study size for each comparison).