Cochrane reviews may include narrative summaries of the main characteristics and results of included economic studies, including measures of incremental resource use, cost and cost-effectiveness, to supplement and provide a commentary on tabulated results. This can be located in the Results section, alongside narrative summary of the results of effectiveness studies (see Chapter 11, Section 11.7)
The central aim of this narrative summary is to make explicit, for the end-user, the extent to which cost and resource use estimates collected from multiple studies are homogeneous between studies. This can be accomplished by describing differences in methods for assessing, and patterns of, resource use and costs between comparison groups, both within and across included studies, with potential explanations for any inconsistencies in results between studies. As discussed earlier in this chapter, economic evaluation studies are constructed differently and for different purposes (see also Section 15.1.2). This is one factor that may lead to heterogeneity between studies in their methods and results. Where there is heterogeneity between economics studies in their methods or results, drawing attention to these potential sources of statistical heterogeneity can help to summarize the international economics literature in an explicit way that is likely to be useful to the end-users of reviews (Gilbody 1999). It is important to avoid using this section as a form of analysis leading to recommendations regarding cost-effectiveness (see also Section 15.8).
Other features of good practice in a narrative summary of included health economics studies include:
reporting the overall numbers of health economics studies selected for inclusion in the review, by study design;
outlining the economic questions addressed within included studies;
reporting the designs of included studies;
reporting the analytic viewpoints adopted within included studies;
reporting the time horizons adopted within included studies;
discussion of measures of incremental resource use, costs and/or cost-effectiveness reported within included studies;
reporting measures of uncertainty alongside measures of resource use, costs and/or cost-effectiveness extracted from reports of included studies;
reporting currency and price year alongside estimates of costs extracted from included studies;
adjusting cost estimates extracted from reports of each included study to a common currency and price year, if possible;
highlighting key features of sensitivity analyses undertaken and consistency of results, both within sensitivity analyses and across included studies;
discussion of the overall methodological quality and limitations of included studies;
discussion of the relevance and generalizability of the results of included studies to other jurisdictions and settings; and
discussion of the quality of effectiveness data used in included health economics studies and the relationship between outcomes used and those estimated in the effectiveness component of the Cochrane review.
A further option is to provide links to completed NHS EED or other structured abstracts of full economic evaluation studies, if available. NHS EED structured abstracts include information on both the characteristics and results of full health economic evaluations (see also Section 15.3.2). Some systematic reviews include NHS EED abstracts of included full economic evaluations in an appendix, as well as a narrative summary of the abstracts in the main text of the review (Rodgers 2006, Fayter 2007).