RT Journal Article
T1 Primary versus secondary source of data in observational studies and heterogeneity in meta-analyses of drug effects: a survey of major medical journals
A1 Prada Ramallal, Guillermo José
A1 Roque, Fátima
A1 Herdeiro, Maria Teresa Ferreira
A1 Takkouche, Bahi
A1 Figueiras Guzmán, Adolfo
K1 Observational studies
K1 Meta-analysis
K1 Source of data
K1 Heterogeneity
K1 Drug
K1 Over-the-counter
K1 Out-of-pocket
AB BackgroundThe data from individual observational studies included in meta-analyses of drug effects are collected either from ad hoc methods (i.e. “primary data”) or databases that were established for non-research purposes (i.e. “secondary data”). The use of secondary sources may be prone to measurement bias and confounding due to over-the-counter and out-of-pocket drug consumption, or non-adherence to treatment. In fact, it has been noted that failing to consider the origin of the data as a potential cause of heterogeneity may change the conclusions of a meta-analysis. We aimed to assess to what extent the origin of data is explored as a source of heterogeneity in meta-analyses of observational studies.MethodsWe searched for meta-analyses of drugs effects published between 2012 and 2018 in general and internal medicine journals with an impact factor > 15. We evaluated, when reported, the type of data source (primary vs secondary) used in the individual observational studies included in each meta-analysis, and the exposure- and outcome-related variables included in sensitivity, subgroup or meta-regression analyses.ResultsWe found 217 articles, 23 of which fulfilled our eligibility criteria. Eight meta-analyses (8/23, 34.8%) reported the source of data. Three meta-analyses (3/23, 13.0%) included the method of outcome assessment as a variable in the analysis of heterogeneity, and only one compared and discussed the results considering the different sources of data (primary vs secondary).ConclusionsIn meta-analyses of drug effects published in seven high impact general medicine journals, the origin of the data, either primary or secondary, is underexplored as a source of heterogeneity
PB BMC
YR 2018
FD 2018
LK http://hdl.handle.net/10347/22232
UL http://hdl.handle.net/10347/22232
LA eng
NO Prada-Ramallal, G., Roque, F., Herdeiro, M.T. et al. Primary versus secondary source of data in observational studies and heterogeneity in meta-analyses of drug effects: a survey of major medical journals. BMC Med Res Methodol 18, 97 (2018)
DS Minerva
RD 28 abr 2026