Methods
In December 2013, a systematic search for economic literature on the cost-effectiveness of LVADs was performed by consulting various databases. First, reviews on this topic were searched by consulting the HTA database produced by the Centre for Reviews and Dissemination (CRD HTA) and websites of HTA institutes mentioned on the International Network of Agencies for Health Technology Assessment (INAHTA) website (www.inahta.net). Websites of non-member HTA institutes such as NICE (www.nice.org.uk) were also checked for relevant analyses. Furthermore, the CRD National Health Service Economic Evaluation Database (NHS EED), Medline (OVID) and EMBASE databases were searched to retrieve both full economic evaluations and reviews of full economic evaluations of LVADs as destination therapy. No restrictions on publication date and language were imposed. Details of the original search strategy performed in January 2011 are available in the appendix of the full HTA report. The search strategy in these databases was performed by one researcher, transparently reported, and validated afterwards by a second researcher. The update in December 2013 was performed with a similar approach.
All retrieved references were assessed against pre-defined selection criteria (Table 1). The selection was restricted to patients with end-stage heart failure receiving an LVAD as destination therapy. Patients with an LVAD as BTT were excluded. Only full economic evaluations were included, i.e., the comparative analysis of at least two alternative interventions in terms of both costs and outcomes. Partial evaluations such as cost analysis were excluded.
The selection of relevant articles was performed in a two-step procedure: initial assessment of the title, abstract, and keywords, followed by a full-text assessment of the selected references. This procedure was in first instance performed by an economist (MN). To improve the quality of this procedure, a physician (JV) checked the medical selection criteria. In case of doubt, the opinion of a third researcher (AV) was asked. Reference lists of the selected studies were checked for additional relevant citations. Figure 1 provides the flow chart of this process. Most articles were excluded due to not being a full economic evaluation (design). In the end, seven relevant studies were selected. Two studies represented the same analysis and were discussed as one study. These full economic evaluations were summarized by a health economist in an in-house developed structured data extraction sheet. These working documents provided the basis of this overview, in which the models' input variables were compared with the systematically identified evidence and with real-world data from the Dutch University Medical Centre Utrecht.
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Figure 1.
Selection of relevant articles. *For this special issue on LVADs, the original search performed in January 2011 was updated in December 2013. Of the seven identified references (5–11), presented the same analysis and were discussed as one. LVADs, left ventricular assist devices; HTA, health technology assessment; CRD, Centre for Reviews and Dissemination.