Calcium channel blockers for preventing acute tubular necrosis in kidney transplant recipients

Need for quality improvement in renal systematic reviews

BACKGROUND AND OBJECTIVES

Systematic reviews of clinical studies aim to compile best available evidence for various diagnosis and treatment options. This study assessed the methodologic quality of all systematic reviews relevant to the practice of nephrology published in 2005.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We searched electronic databases (Medline, Embase, American College of Physicians Journal Club, Cochrane) and hand searched Cochrane renal group records. Clinical practice guidelines, case reports, narrative reviews, and pooled individual patient data meta-analyses were excluded. Methodologic quality was measured using a validated questionnaire (Overview Quality Assessment Questionnaire). For reviews of randomized trials, we also evaluated adherence to recommended reporting guidelines (Quality of Reporting of Meta-Analyses).

RESULTS

Ninety renal systematic reviews were published in year 2005, 60 of which focused on therapy. Many systematic reviews (54%) had major methodologic flaws. The most common review flaws were failure to assess the methodologic quality of included primary studies and failure to minimize bias in study inclusion. Only 2% of reviews of randomized trials fully adhered to reporting guidelines. A minority of journals (four of 48) endorsed adherence to consensus guidelines for review reporting, and these journals published systematic reviews of higher methodologic quality (P < 0.001).

CONCLUSIONS

The majority of systematic reviews had major methodologic flaws. The majority of journals do not endorse consensus guidelines for review reporting in their instructions to authors; however, journals that recommended such adherence published systemic reviews of higher methodologic quality.

Calcium channel blockers for preventing acute tubular necrosis in kidney transplant recipients

BACKGROUND

The incidence of delayed graft function in cadaveric grafts has increased over the last few years due in part to the large demand for cadaveric kidneys necessitating the use of kidneys from marginal donors. Calcium channel blockers have the potential to reduce the incidence of post-transplant acute tubular necrosis (ATN) if given in the peri-operative period. However, there is controversy surrounding their use in this situation with no consensus as to their efficacy.

OBJECTIVES

To evaluate the benefits and harms of using calcium channel blockers in the peri-transplant period in patients at risk of ATN following cadaveric kidney transplantation.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library) MEDLINE (from 1966) and EMBASE (from 1980). The Trials Search Coordinator was contacted to develop the search strategy. Date of last search: January 2007

SELECTION CRITERIA

Randomised controlled trials comparing calcium channel blockers given in the peri-transplant period with controls were included. Quasi-randomised trials were excluded.

DATA COLLECTION AND ANALYSIS

Data was extracted and quality assessed independently by two reviewers, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and measurements on continuous scales are reported as mean differences (WMD) with 95% confidence intervals (CI).

MAIN RESULTS

Thirteen trials (724 participants) were suitable for inclusion. Treatment with calcium channel blockers in the peri-transplant period was associated with a significant decrease in the incidence of post-transplant ATN (RR 0.62, 95% CI 0.46 to 0.85) and delayed graft function (RR 0.55, 95% CI 0.42 to 0.73). There was no difference between control and treatment groups in graft loss, mortality, requirement for haemodialysis. There was insufficient information to comment on adverse events.

AUTHORS' CONCLUSIONS

These results suggest that calcium channel blockers given in the peri-operative period may reduce the incidence of ATN post-transplantation. The result should be treated with caution due to the heterogeneity of the trials which made comparison of studies and pooling of data difficult.