Background: The use of systematic reviews to inform public health policy has become increasingly common in recent years. A key criticism of systematic reviews intended for public health policy makers has been that they lack clarity and are difficult to interpret, especially when they lack quantitative syntheses.
Objectives: Describe challenges faced when attempting to avoid ambiguity in a systematic review conducted for the Drug Effectiveness Review Project (DERP), a collaboration of organizations that is funded by multiple US state Medicaid programs.
Methods: We conducted a systematic review of the comparative effectiveness and safety of psychostimulants and atomoxetine for adult attention deficit and hyperactivity disorder (ADHD). Here we review our process of formulating our data synthesis approach.
Results: One head-to-head and 20 placebo-controlled trials were included. The first challenge was in deciding whether it was sensible to conduct a meta-analysis of the indirect comparative efficacy and safety of drugs across placebo-controlled trials. Considering the heterogeneity in populations and methods of outcome reporting, we decided against this approach. The other big challenge was in identifying the optimal approach to the qualitative synthesis. The main difficulty was in identifying the most meaningful way, if any, to group and tabulate outcome data, considering the heterogeneity in reporting methods. We consulted the review methods outlined in the Cochrane Handbook for Systematic Reviews of Interventions and by the Centre for Reviews and Dissemination, University of York, for support, but did not identify any other recent practical guide materials specific to conducting drug class reviews for use in public policy forums.
Conclusions: Further work is needed to define optimal approaches to qualitative evidence synthesis in systematic drug class reviews for use in public policy forums. Dissemination of the experiences of systematic reviewers with DERP and other such groups will contribute to the development of models for the qualitative synthesis of evidence.