Whether temporal discounting is domain-specific between health outcomes and money: a systematic review and meta-analysis

Background: Temporal discounting, the preference for immediate over delayed rewards, affects decision-making in domains like health and finance. Understanding the differences in how people discount health outcomes compared to monetary rewards is crucial to shaping health policy and technology assessments.

Aim: This systematic review and meta-analysis aimed to compare temporal discounting parameters between health outcomes and monetary rewards and evaluate their overall relationship.

Method: Studies were retrieved from PubMed, Embase, Web of Science, and the Cochrane Library up to December 2023. Standardized mean differences (SMD) assessed discounting differences between statistical indicators, and correlation coefficients were transformed into Fisher's Z scores. Subgroup analyses based on population, tradability, magnitude, sign, and experimental process explored potential heterogeneity.

Results: A total of 32 studies were included: 29 studies (47 pairs of health and money) for the comparative meta-analysis and 19 studies (32 pairs) for the correlation meta-analysis. No significant differences were found between health and money discounting, although the individuals were more patient with the health outcomes and more impulsive with the money. In the sign effect subgroup, health discounting for delayed losses was lower than for monetary losses (SMD: - 0.293; 95% CI: - 0.458, - 0.129). The pooled correlation coefficient (r) for all studies was 0.333 (95% CI: 0.283-0.383), indicating a moderate association. In subgroup analysis, when the indicator was the discount rate, the pooled r value for 16 studies was 0.278 (95% CI: 0.231, 0.325).

Conclusion: Although no significant statistical differences were found between health and money discounting, a moderate correlation was observed, supporting consistent discount rate settings for health technology assessments.