Studies without statistical data presentation, and those where cases were potentially overlapping between publications, were considered in a narrative synthesis.
If publications reported on the same sample or on overlapping samples, the publication providing the maximum of information was included in the meta-analysis.
However, overlapping with the publication of progress made, an independent report has been published on the use of the Liverpool Care Pathway (LCP) in the UK, highlighting public concern over the quality of care provided at the end of life (Department of Health, 2013).
We randomly selected 20 topics with overlapping meta-analyses publications and a pair of meta-analyses from each (40 articles total) and examined the extent of overlap in the outcomes and whether the more recently published meta-analysis (the one with the higher PubMed ID number) had any additional outcomes evaluated with quantitative synthesis compared with the older meta-analysis.
Even though the antibodies used to detect leukocytes in some of these studies have themselves overlapping specificities, a recent publication using a mouse model of liver injury showed that most FSP1-positive cells stained positively for F4/80, which is at present the most specific marker for macrophages [ 21].
We excluded the following: (1) studies with overlapping data or duplicate publications; (2) the genotype distributions that could not be ascertained or calculated; (3) the study subject who was not human.
16 Eligible guidelines should have been published either originally or in an updated form between 1 January 2010 and 31 December 2013, a timeframe that was chosen to allow for the inclusion of IPD meta-analyses from our sample; albeit that we accepted a one year overlap between publication of guidelines and meta-analyses in 2010.
Although we attempted to describe trends in anemia management in relation to secular events, we cannot make causal inferences, as clinical trial publications overlapped with changes in product label regulations and in reimbursement.
Because some online publication search engines index multiple publication sources whose coverage of publications may overlap, it is not uncommon for a search query to return several records that correspond to the same publication.
All retrieved articles were then compared and from overlapping series of patients only the most recent publication was accepted.
