Interventions:
The interventions were well described. The comparator was appropriate as it appeared to have reflected usual care in the study setting.
Effectiveness/benefits:
Clinical and effectiveness data were from published and unpublished studies. The authors did not report whether a systematic review of the literature was undertaken, so it was not possible to determine whether all relevant information was included in the model. QALYs were a valid benefit measure, as HIV has an impact both on quality of life and survival. They also allow comparisons with other disease areas. Limited information was provided on the estimation of the utility values, but the sources of references were reported. The authors did not report if future QALYs were discounted, which appeared to have been relevant given the lifetime horizon of the analysis.
Costs:
The perspectives were explicitly reported to have been that of the health care payer and public health. For these perspectives it appears that all major relevant costs were included in the analysis. The sources for these costs were adequately reported and were for the US setting. The time horizon was the lifetime of the patient, the authors did not state whether future costs were discounted. The price year was not reported, which would hamper future inflationary exercises.
Analysis and results:
An appropriate incremental approach was used to synthesise the costs and benefits of the alternative testing strategies. Uncertainty was investigated using a determinist approach, which focused on variations in individual inputs, but a probabilistic sensitivity analysis would have captured the full impact of parameter uncertainty on the results. As a main limitation to the study, the authors reported that reimbursement for the fourth-generation assay was not widely established, so its cost had to be assumed.
Concluding remarks:
The methods, analyses, and results were mostly clear and comprehensive, but some model inputs were uncertain making it hard to assess the authors’ conclusions.