TRENDS IN UTILITY ELICITATION METHODS: IS THERE STILL A ROLE FOR DIRECT ELICITATION?

Purpose: To identify trends in the use of direct and indirect utility elicitation techniques in published cost-effectiveness analyses.

Method: We analyzed data extracted from cost-effectiveness analyses (CEAs) included in the Tufts Medical Center Cost-effectiveness Analysis Registry, a database with detailed information on CEAs published in the peer-reviewed medical and economic literatures.  Using studies from 1991-2008, we analyzed the proportion of utility weights elicited using direct vs. indirect methods, type of direct or indirect elicitation method, source of weights, age of the population affected by the disease, and disease category.  Trends over time were assessed by comparing the 1991-93 and 2006-08 periods.

Result: For CEAs published from 1991 to 2008, 42% of utility weights were elicited using direct elicitation methods, 35% using indirect methods, and methods were unknown for 23%.  For adult utility weights, the rating scale was the most commonly used direct method (25% for ‘91-‘93 and ‘06-‘08).  For children, author/clinician judgment was most commonly reported as the “direct” method in earlier years (91%) compared with the standard gamble later (31%).  For the elderly, the time trade-off was the most commonly reported direct method for both periods (33% and 18%, with 50% unreported in both periods).  The most commonly used indirect method in the later period was the EQ-5D for adults (28%) and elderly (23%), and the HUI for children’s states (25%).  Source of the utility weight also varied over time:  for adult weights, the most common source changed from clinicians to patients for children, from authors to proxies; and for elderly, from proxies to patients.  Specific characteristics of utility weights were missing for 6-60% of utility weights depending on the year, with fewer missing in later years.  Few CEAs specific to children or elderly target populations were reported in earlier years.

Conclusion: Published guidelines recommend the use of generic instruments and trends over time show increasing adherence to these recommendations. In recent years, fewer studies have used authors or clinicians to estimate utility weights and more have used indirect methods.  Nevertheless, the substantial proportion of CEAs using direct elicitation methods suggests there may be a continued role for direct elicitation.  Future research should explore conditions under which a direct elicitation approach may be warranted.