Heterogeneity in Cost-Effectiveness Analysis of Vaccination for Mild and Moderate Alzheimer's Disease

Immunotherapy for Alzheimer's disease(AD) has gained momentum in recent years. One of the concerns over its application pertains to Cost-Effectiveness Analysis (CEA) from population average and specific subgroup differences, as such a therapy is imperative for health decisionmakers to allocate limited resources. However, this sort of CEA model considering heterogeneous population with risk factors adjustment has been rarely addressed.

We aimed to show the heterogeneity of CEA in immunotherapy for AD in comparison with the comparator without intervention. Economic evaluation was performed via incremental Cost- Effectiveness Ratio (ICER) and Cost-Effectiveness Acceptability Curve (CEAC) in terms of the Quality- Adjusted Life Years (QALY). First, population-average CEA was performed with and without adjustment for age and gender. Secondly, sub-group CEA was performed with the stratification of gender and age based on Markov process.

Given the threshold of $20,000 of willingness to pay, the results of ICER without and with adjustment for age and gender revealed similar results ($14,691/QALY and $17,604/QALY). The subgroup ICER results by different age groups and gender showed substantial differences. The CEAC showed that the probability of being cost-effective was only 48.8%-53.3% in terms of QALY at population level but varied from 83.5% in women aged 50-64 years, following women aged 65-74 years and decreased to 0.2% in men≥ 75 years.

There were considerable heterogeneities observed in the CEA of vaccination for AD. As with the development of personalized medicine, the CEA results assessed by health decision-maker should not only be considered by population-average level but also specific sub-group levels.