Incorporating process utility into cost-effectiveness analysis via a bolt-on domain to the SF-6D : an exploratory study

Background

Within the UK, standard methods of economic evaluation centre on the maximisation of the quality-adjusted life-year (QALY). However, preference-based measures used to estimate QALYs may not be suited to all economic evaluations, as they routinely measure only health outcomes.

Aim

This study used an economic evaluation alongside a clinical trial (EEACT) comparing patients’ preferences for a telephone versus a face-to-face consultation to incorporate process utility into cost-effectiveness analyses.

Methods

An EEACT is described that generates QALYs using Short-form 6-dimension version 1 (SF-6Dv1) responses. These results exclude specific consideration of process utility. A health state valuation study is then reported that bolts a process domain onto the SF-6Dv1 using data obtained from the EEACT. These results therefore include the consideration of process utility. The results of the EEACT with and without process utility are then compared.

Results

This study shows that the QALY, in its current form, does not capture patient benefits associated with the process of receiving healthcare. The EEACT illustrates this, showing a statistically significant difference between control and intervention groups for the patient experience questionnaire communication domain, indicating that patients preferred the intervention. This preference was not identified in the cost-effectiveness outcomes, and the point estimates lie in the north-west quadrant of the cost-effectiveness plane. The preference is captured after adding a communication domain. The point estimate moves to the north-east quadrant, where the intervention is more effective and more costly than the control.

Conclusion

This study indicates that it is possible to capture patients’ preferences for processes associated with care, in a format compatible with the QALY.