Fish oil for kidney transplant recipients.

BACKGROUND

Calcineurin inhibitors used in kidney transplantation for immunosuppression have adverse effects that may contribute to nephrotoxicity and increased cardiovascular risk profile. Fish oils are rich in very long chain omega-3 fatty acids, which may reduce nephrotoxicity by improving endothelial function and reduce rejection rates through their immuno-modulatory effects. They may also modify the cardiovascular risk profile. Hence, fish oils may potentially prolong graft survival and reduce cardiovascular mortality.

OBJECTIVES

To assess the benefits and harms of fish oil supplementation on kidney transplant recipients on a calcineurin inhibitor-based immunosuppressive regimen.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library, issue 2 2005), MEDLINE (1966-April 2005) and EMBASE (1980-April 2005).

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs of fish oils in kidney transplant recipients on a calcineurin inhibitor-based immunosuppressive regimen. RCTs of fish oil versus statins were included.

DATA COLLECTION AND ANALYSIS

Data was extracted and the quality of studies assessed by two authors, with differences resolved by discussion with a third independent author. Dichotomous outcomes were reported as relative risk (RR) and continuous outcome measures were reported as the mean difference (MD) with 95% confidence intervals using the random effects model. Heterogeneity was assessed using a Chi(2) test on n-1 degrees of freedom and the I(2) statistic. Data not suitable for pooling were tabulated and described.

MAIN RESULTS

Sixteen studies (733 patients) were suitable for analysis. Fish oil did not significantly affect patient or graft survival, acute rejection rates, calcineurin inhibitor toxicity or renal function, when compared to placebo. Fish oil treatment was associated with a lower diastolic blood pressure (MD 4.5 mmHg; P = 0.004) compared to placebo. Patients receiving fish oil for more than six months had a modest increase in HDL (MD 0.12 mmol/L; P = 0.01) compared to placebo. Fish oil effects on lipids were not significantly different from low-dose statins. There was insufficient data to analyse cardiovascular outcomes. Fishy aftertaste and gastrointestinal upset were common but did not result in significant patient drop-out.

AUTHORS' CONCLUSIONS: There is insufficient evidence from currently available RCTs to recommend fish oil therapy to improve renal function, rejection rates, patient survival or graft survival. The improvements in HDL cholesterol and diastolic blood pressure were too modest to recommend routine use. To determine a benefit in clinical outcomes, future RCTs will need to be adequately powered with these outcomes in mind.