In some patient groups, different blood pressure lowering drugs have differing relative beneficial and harmful effects in addition to their blood pressure lowering action. We investigated whether different classes of drugs might have different relative effects in kidney transplant patients. We found that calcium channel blockers (CCB) reduced the risk of graft loss by about 25% in randomised studies, compared to placebo or no treatment. CCB also improved the function of grafts, as measured by glomerular filtration rate (GFR) with GFR 4.5 mL/min higher on average in patients receiving CCB compared to placebo. There were fewer studies comparing angiotensin converting enzyme inhibitors (ACEi) to placebo and their results were inconclusive. In studies that compared ACEi to CCB, ACEi worsened GFR by about 11.5 mL/min on average. ACEi also lowered haemoglobin and increased the risk of elevated blood potassium compared to CCB. There were not enough studies of other classes of drugs to draw conclusions about their relative effects. On current evidence CCB might therefore be the best agents for kidney transplant patients.
These data suggest that CCB may be preferred as first line agents for hypertensive kidney transplant recipients. ACEi have some detrimental effects in kidney transplant recipients. More high quality studies reporting patient centred outcomes are required.
In some nontransplant populations, effects of different antihypertensive drug classes vary. Relative effects in kidney transplant recipients are uncertain.
To assess comparative effects of different classes of antihypertensive agents in kidney transplant recipients.
MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, conference proceedings and reference lists of identified studies were searched.
Randomised controlled trials of any antihypertensive agent applied to kidney transplant recipients for at least two weeks were included.
Data was extracted by two investigators independently. Study quality, transplant outcomes and other patient centred outcomes were assessed using random effects meta-analysis. Risk ratios (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes, both with 95% confidence intervals (CI) were calculated. Stratified analyses and meta-regression were used to investigate heterogeneity.
We identified 60 studies, enrolling 3802 recipients. Twenty-nine studies (2262 participants) compared calcium channel blockers (CCB) to placebo/no treatment, 10 studies (445 participants) compared angiotensin converting enzyme inhibitors (ACEi) to placebo/no treatment and seven studies (405 participants) compared CCB to ACEi. 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) and improved glomerular filtration rate (GFR), (MD, 4.45 mL/min, 95% CI 2.22 to 6.68). 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), proteinuria (MD -0.28 g/24 h, 95% CI -0.47 to -0.10), haemoglobin (MD -12.96 g/L, 95% CI -5.72 to -10.21) and increased hyperkalaemia (RR 3.74, 95% CI 1.89 to 7.43). Graft loss data were inconclusive (RR 7.37, 95% CI 0.39 to 140.35). Other drug comparisons were compared in small numbers of participants and studies.