Figure 2From: A systematic review of individual patient data meta-analyses on surgical interventions Number of applied IPDMA published up to April 2012,* as identified by a systematic review of PubMed, Embase, Web of Science, and the Cochrane Library. *Thirty-seven IPDMAs published in 2012 were identified up to 24 April 2012, when the review was conducted.Back to article page