Background: Kidney transplantation is the treatment of choice for most patients with end-stage renal disease (ESRD). Standard protocols in use typically involve three drug groups each directed to a site in the T-cell activation or proliferation cascade which are central to the rejection process: calcineurin inhibitors (e.g. cyclosporin, tacrolimus), anti-proliferative agents (e.g. azathioprine, mycophenolate mofetil) and steroids (prednisolone). It remains unclear whether new regimens are more specific or simply more potent immunosuppressants.
Objectives: To compare the effects of tacrolimus with cyclosporin as primary therapy for kidney transplant recipients.
Search strategy: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, the Cochrane Renal Group's specialist register and conference proceedings were searched to identify relevant reports of randomised controlled trials (RCTs). Two reviewers assessed trials for eligibility, quality and extracted data independently.
Selection criteria: All RCTs where tacrolimus was compared with cyclosporin for the initial treatment of kidney transplant recipients
Data collection and analysis: Data were synthesised (random effects model) and results expressed as relative risk (RR), values <1 favouring tacrolimus, with 95% confidence intervals (CI). Subgroup analysis and meta-regression were used to examine potential effect modification by differences in trial design and immunosuppressive co-interventions.
Main results: 123 reports from 30 trials (4102 patients) were included. At six months graft loss was significantly reduced in tacrolimus-treated recipients (RR 0.56, 95% CI 0.36 to 0.86), and this effect was persistent up to three years. Meta-regression showed that this benefit diminished as higher trough levels of tacrolimus were targeted (P = 0.04), after allowing for differences in cyclosporin formulation (P = 0.97) and cyclosporin target trough level (P = 0.38). At one year, tacrolimus patients suffered less acute rejection (RR 0.69, 95% CI 0.60 to 0.79), and less steroid-resistant rejection (RR 0.49, 95% CI 0.37 to 0.64), but more insulin-requiring diabetes mellitus (RR 1.86, 1.11 to 3.09), tremor, headache, diarrhoea, dyspepsia and vomiting. Cyclosporin-treated recipients experienced significantly more constipation and cosmetic side-effects. We demonstrated no differences in infection or malignancy.
Authors' conclusions: Tacrolimus is superior to cyclosporin in improving graft survival and preventing acute rejection after kidney transplantation, but increases post-transplant diabetes, neurological and gastrointestinal side effects. Treating 100 recipients with tacrolimus instead of cyclosporin would avoid 12 suffering acute rejection, two losing their graft but cause an extra five to become insulin-requiring diabetics.