Evidence-based medicine in nephrology: identifying and critically appraising the literature

Background. Uncertainties about best management of end-stage renal disease (ESRD) are reflected in wide variations in practice. Systematic reviews aim to reduce uncertainty by strengthening the evidence base for clinical practice, allowing estimation of the benefits and risks of particular interventions, whilst minimizing the potential for bias. This paper describes the methods and conduct of six systematic reviews of aspects of the management of ESRD, and the yield in terms of trials found. Methods. Our methodology was based on that recommended by the Cochrane Collaboration (an international initiative set up to perform and disseminate systematic reviews of health care). It involved a systematic search of electronic databases and bibliographic reference lists, together with handsearching of Kidney International for studies relevant to the management of ESRD, followed by a systematic assessment of study quality. Results. Around 12000 abstracts were assessed which had been identified from electronic sources. Of these, 2085 (18%) were deemed to be reports of possible randomized or quasi-randomized controlled trials relevant to the management of ESRD. Three hundred and forty were relevant to the six specific reviews, and after assessment of the full manuscripts, 39 studies were finally included in our reviews. Reports of a further nine trials, which were identified from other sources, were also included. The broad search adopted allowed the parallel development of a register of trials of all aspects of the management of ESRD. Conclusions. This study has demonstrated that the methodology of systematic reviews, as promoted by the Cochrane Renal Group, is feasible but has significant resource implications. The development of a register of randomized controlled trials (RCTs) related to the management of ESRD will facilitate this form of research in the future.