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Multicohort models in cost-effectiveness analysis: why aggregating estimates over multiple cohorts can hide useful
James F O'Mahony1,2, Joost van Rosmalen1, Ann G Zauber3
1Department of Public Health, Erasmus MC, Erasmus University, Rotterdam, the Netherlands (JFO’M, JvR, MvB)
Aggregating cost-effectiveness analysis (CEA) estimates across multiple patient cohorts can obscure important differences. Analyzing per-cohort data is crucial for accurate health policy decisions in screening programs.
Area of Science:
- Health economics
- Public health policy
- Screening program evaluation
Background:
- Cost-effectiveness analysis (CEA) models for screening programs can utilize single or multiple birth cohorts.
- Real-world screening implementation often involves multiple concurrent patient cohorts due to long-term, multi-stage screening processes.
- While modeling all cohorts is advocated for accuracy, aggregating estimates masks cohort-specific cost-effectiveness variations.
Purpose of the Study:
- To demonstrate the drawbacks of combining cost-effectiveness estimates from multiple cohorts without examining individual cohort data.
- To highlight how aggregated estimates can lead to different policy recommendations compared to per-cohort analyses.
- To illustrate potential disadvantages of aggregating CEA estimates across cohorts in screening programs.
Main Methods:
- Developed a multicohort model to estimate the cost-effectiveness of two alternative cervical screening tests.
- Compared aggregated cost-effectiveness estimates with per-cohort estimates.
- Analyzed scenarios where policy choices differed based on aggregated versus disaggregated results.
Main Results:
- Identified instances where aggregated and per-cohort cost-effectiveness estimates suggested different optimal policy choices.
- Demonstrated that aggregating estimates can obscure significant heterogeneity in cost-effectiveness across cohorts.
- Highlighted the policy relevance of variations in cost-effectiveness, particularly in cancer screening with concurrent birth cohorts.
Conclusions:
- The recommendation to consider multiple cohorts in CEA is valid.
- Aggregating cost-effectiveness estimates across multiple cohorts into a single figure is not advisable.
- Per-cohort analysis is essential for nuanced and accurate policy recommendations in screening programs.
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