Evaluating willingness-to-pay thresholds for dementia caregiving interventions: application to the tailored activity program

Abstract

Objectives: The study aims to apply willingness-to-pay (WTP) values derived from the literature to inform decision-makers of the cost-effectiveness of the Tailored Activity Program (TAP), an intervention proven to reduce caregiver burden.

Methods: TAP and other caregiver interventions employ an individual perspective and non-quality-adjusted life-year (QALY) outcome measure where the primary objective is to determine caregiver burden from an individual perspective. Therefore, standard cost/QALY thresholds are not appropriate. To identify relevant WTP values, we searched for studies that: 1) were published in the past 5 years and used contingent valuation methodology to identify WTP; 2) assessed WTP for a dementia-related intervention requiring out-of-pocket expenditure; and 3) asked caregivers their WTP for an outcome related to reducing caregiver burden. Three studies were identified utilizing four WTP values. We also assessed potential financial savings that caregivers could achieve from purchasing TAP. To assess the probability of TAP being cost-effective, we built a Monte Carlo simulation to test the four WTP values applied to two TAP outcome measures: reduction in caregiver hours "on duty;" and "doing things."

Results: For outcome measure "on duty," WTP varied between $1.06/hour and $4.58/hour. For outcome measure "doing things," WTP varied between $2.21/hour and $9.57/hour. Applying the four identified WTP values from the literature to TAP outcomes resulted in TAP cost-effectiveness varying between 50% and 80% for both outcome measures.

Conclusions: When WTP data are not collected prospectively or conventional metrics cannot be applied, retrospectively assessing literature-derived WTP may be acceptable for informing decision-makers of potential cost-effectiveness of a proven program. Application of WTP to TAP shows potential cost-effectiveness that can be expected under the tested WTP scenarios.

Figure 1

Acceptability curves for outcome measure “On Duty” and “Doing Things.” *One less hour is equivalent to one more hour of free time.