The search terms used to identify cost of illness studies differed from those used for cost effectiveness studies. For the Medline database search terms “exp “costs and cost analysis” OR costs.tw. OR cost.tw.” was used. This algorithm had a sensitivity of 95% and a specificity of 95.6% (Wilczynski et al. 2004). The search algorithm “cost.mp. OR costs.tw. OR health care costs.sh.” was used for the EMBASE search and has a sensitivity of 96.8% and specificity of 97.6%.
There is currently no formal tool or checklist for the critical appraisal of the quality of cost of illness studies. Therefore, for this analysis, a modified version of a checklist presented by Larg and Moss (2011) in a critical analysis of cost of illness studies was used. This checklist focused on three major areas: 1) Analytical framework of the study, 2) Methodology and data collection and 3) Cost analysis and reporting.
Similar to the review of cost effectiveness studies, a brief summary of each study will be reported. Costs were converted to 2018 US dollars by converting currency through the Organisation for Economic Co-operation and Development (2014) reported purchasing price parity and then inflating the cost to 2018 values through United States consumer price index for medical care (United States Department of Labour 2014).