Making systematic reviews more useful for policy-makers.
Year: 2005
Type: review
Abstract: Editor – The Mexico Summit has high-lighted the need to improve evidence for informed policy-making about health concerns in low- and middle-income countries (LMICs). We agree with Volmink et al. who, in a recent article published in the Bulletin, asserted that systematic reviews provide the most useful type of evidence for determining the effectiveness of health care interven-tions (1). Other authors have focused on how policy-makers can interpret systematic reviews (2), and have called for more reviews of health problems in LMICs (1, 3).However, as highlighted by Langer et al. in another recent Bulletin article, the evidence in most systematic reviews originates from high-income countries (4). This is likely to continue to be the case for the foreseeable future. Evidence-based policy-making in LMICs would benefit if the applicability of reviews con-ducted elsewhere could be maximized.Use of health-care interventions in LMICs often depends on factors such as the resources available, the organization of health services, cultural norms, and the physical environment. Considering such contextual factors can enhance the generalizability of sys-tematic reviews and their usefulness to policy-makers in diverse settings. This process is analogous to that of improv-ing the internal validity of systematic reviews by considering inter-study variations in participants, study design, and analytic methods (5). A structured approach for dealing with contextual variation can be either extrinsic or intrinsic to the review process.An extrinsic approach requires re-viewers to give some context-dependent guidance for applying a review’s findings. Although the reviewers may not have an in-depth knowledge of all circumstances, they often have considerable expertise in the intervention and alternatives. Furthermore, reviews often provide an opportunity to evaluate studies con-ducted in a variety of settings. Generaliz-ability can be tackled by considering the following questions:1. Relative importance of the health problem: Do the occurrence and se-verity of the health problem vary sig-nificantly between settings and how might this affect the intervention’s potential benefit to the population? 2. Relevance of outcome measures: Are there different outcome measures that might be more or less meaningful in different settings? 3. Practicality of the intervention: What factors, if any, might significantly affect the feasibility of the interven-tion in different settings? 4. Appropriateness of the intervention: Are there other interventions for achieving the stated goal that might be more appropriate in some settings? 5. Cost-effectiveness of the intervention: Are the costs and benefits of the intervention likely to differ signifi-cantly across settings?Addressing these questions may take as little as one or two paragraphs. Using the example of the effect of streptoki-nase for the treatment of myocardial infarction, such a paragraph could read: “Acute myocardial infarction is an im-portant problem in all populations and cultures. Streptokinase is an interven-tion that can be effectively provided in settings where medications can be given intravenously. Alternative treatments do exist, some of which are considerably cheaper (e.g. aspirin), while others are considerably more expensive (e.g. tissue plasminogen activating factor, angio-plasty, etc). Other reviews have com-pared the effectiveness of some alterna-tives with that of streptokinase. The relative beneficial effect of streptokinase compared to no treatment is likely to be consistent across different risk groups in a range of populations. The cost of streptokinase (around US$ 30 per dose) may vary in different countries. While it is considered a cheap intervention in developed countries, it is relatively expensive in developing countries.”Alternatively, in an intrinsic ap-proach, important contextual dimen-sions are addressed through planned stratification or subgroup analyses. We recently used this approach in a Cochrane Review of the effectiveness of specialist outreach clinics compared with hospital outpatient clinics (6). A total of 73 studies were identified reporting outreach to nearby urban clin-ics, such as in the United Kingdom, or to rural communities, including remote populations in Africa, Latin America, Australia and Canada. In some studies outreach was targeted at general popu-lations and in others at disadvantaged subgroups such as indigenous commu-nities or homeless people. The nature of the intervention, the types of outcomes measured, and the effectiveness of out-reach all varied according to the setting and population, and we stratified studies accordingly. For example, outreach to urban clinics had minimal effect on access, but could improve health out-comes when combined with education sessions or joint consultations. Outreach to rural and disadvantaged populations led to improved access. We also identi-fied a paucity of high-quality compara-tive studies in rural and disadvantaged settings, where outreach has poten-tially the most to offer.Evidence-based public policy-making is a laudable goal in all settings, but relies on making the most of avail-able evidence. Authors, as well as users, can work towards this goal by produc-ing systematic reviews that are widely applicable. OCompeting interests: none declared.Russell L. Gruen
Source: Europe PMC (PubMed Central)
Language: English
Subfield: Statistics, Probability and Uncertainty
Field: Decision Sciences
Domain: Social Sciences
Open Access status: green
OpenAlex ID: W2106451687