Article type
Year
Abstract
Background: The underlying affinity between outcomes that leads to their co-occurrence in a research study identifies central outcomes, i.e. outcomes most important to the connectedness of the network of outcomes. Core outcome sets (COS) are the minimum outcomes that should be measured in research in a field. Current methods to develop COS are inconsistent.
Objectives: We conducted a social network analysis (SNA) of outcomes in systematic reviews (SRs) of HIV/AIDS to understand outcome co-occurrence and compare the most central and the most frequent outcomes.
Methods: We examined all Cochrane SRs of HIV/AIDS as of June 2013 and grouped individual outcomes into 1/14 categories. Our SNA only considered outcomes that co-occurred in ≥ 2 SRs. To identify central outcomes, we used normalized node betweenness centrality (nNBC), i.e. the extent to which connections between other outcomes in a network rely on a given outcome as an intermediary. The higher the nNBC, the more central is the outcome to a network. We identified the 7 most central and most frequent outcomes because the Cochrane Handbook recommends including ≤ 7 main outcomes in SRs. We also examined centrality and frequency of outcomes for the 4 pre-defined HIV/AIDS intervention subgroups: clinical management, biomedical prevention, behavioral prevention, and health services.
Results: 140 SRs, measuring 294 unique outcomes, were eligible. The most central outcomes in the overall network were all-cause mortality (nNBC = 23.9) and cost/cost-effectiveness (nNBC = 16.4; Fig 1). The most central and most frequent outcomes differed overall and for each sub-network. For example, for biomedical prevention, adverse events (specified), a patient-important outcome, was among the most central but not among the most frequent outcomes. Only 4/7 outcomes overlapped between the network and frequency analyses for biomedical prevention (Fig 2).
Conclusions: SNA is a novel application for systematically identifying central outcomes in SRs. Co-occurrence and frequency are both important considerations for developing COS, particularly because the two contribute different information. SNA should be used when developing COS.
Objectives: We conducted a social network analysis (SNA) of outcomes in systematic reviews (SRs) of HIV/AIDS to understand outcome co-occurrence and compare the most central and the most frequent outcomes.
Methods: We examined all Cochrane SRs of HIV/AIDS as of June 2013 and grouped individual outcomes into 1/14 categories. Our SNA only considered outcomes that co-occurred in ≥ 2 SRs. To identify central outcomes, we used normalized node betweenness centrality (nNBC), i.e. the extent to which connections between other outcomes in a network rely on a given outcome as an intermediary. The higher the nNBC, the more central is the outcome to a network. We identified the 7 most central and most frequent outcomes because the Cochrane Handbook recommends including ≤ 7 main outcomes in SRs. We also examined centrality and frequency of outcomes for the 4 pre-defined HIV/AIDS intervention subgroups: clinical management, biomedical prevention, behavioral prevention, and health services.
Results: 140 SRs, measuring 294 unique outcomes, were eligible. The most central outcomes in the overall network were all-cause mortality (nNBC = 23.9) and cost/cost-effectiveness (nNBC = 16.4; Fig 1). The most central and most frequent outcomes differed overall and for each sub-network. For example, for biomedical prevention, adverse events (specified), a patient-important outcome, was among the most central but not among the most frequent outcomes. Only 4/7 outcomes overlapped between the network and frequency analyses for biomedical prevention (Fig 2).
Conclusions: SNA is a novel application for systematically identifying central outcomes in SRs. Co-occurrence and frequency are both important considerations for developing COS, particularly because the two contribute different information. SNA should be used when developing COS.