Individual patient data:

Abstract 

Case presentation

Systematic reviews play an increasingly important role in establishing recognized evidence to guide clinical decision making. The evidence is usually graded on a scale that depends on the reliability of the reviewed material. To take into account any factor affecting the reliability of the conclusions of articles dealing with treatment outcomes, the grading scales of JEBDP are continuously reviewed. The aim of this article is to propose a modification of the JEBDP grading system, to take into account the value of individual patient data (IPD). The availability of IPD may be crucial for assessing the reliability of a systematic review, especially when the influence of patient-related features affect the outcome of therapy. We use simulated and published data to illustrate the role of IPD in assessing the contribution of individual prognostic factors to the final outcome and in preventing ecological bias.