Chapter 6 Discussion

Blood safety is a critical and data-rich area of health policy, making it an ideal domain for decision-analytic modeling. To date, various model-based blood safety policy analyses have been performed, mostly to evaluate disease marker testing and pathogen inactivation interventions. However, there remain numerous opportunities for improving the methodology and utilization of model-based analyses within the policymaking process.

The four projects described in this dissertation yield insights that are directly applicable to current blood safety policy decisions. Specific insights include:

  • The U.S. policy of screening all donations for Zika virus was not cost effective at the peak of the epidemic. Now that Zika incidence has largely subsided, the benefits of continued screening are vanishingly small.

  • Whole blood pathogen inactivation may be cost-saving in Ghana and other sub-Saharan African health systems, and transfusion-transmitted bacterial sepsis is an underappreciated transfusion-related adverse event.

  • The optimal blood safety portfolio can vary considerably by geography, donor characteristics, and over time as epidemiologic conditions shift. This suggests that more frequent updating of blood safety policies in light of changing conditions could increase efficiency.

  • Blood donors exhibit considerable heterogeneity in their post-donation iron recovery and risk of iron-related adverse donation outcomes as a function of time between donation attempts. This suggests that tailored donation intervals could out-perform the current one-size-fits-all approach in balancing risks to blood donors and the adequacy of the blood supply.

Additionally, this dissertation includes methodological innovations that can be applied in other health systems or to evaluate other blood safety interventions. Namely:

  • The recipient-level microsimulation developed for the Zika analysis models the relationship between the number and type of blood components transfused and recipient characteristics such as age and baseline expected post-transfusion survival. For chronic viral infections such as HIV, HBV, and HCV, differences in recipient characteristics may have an even greater influence on the estimated costs and health utility loss from adverse events.

  • The approach to accounting for the timing of clinical detection and treatment initiation for transfusion-related adverse events in the pathogen inactivation analysis can be used in assessments of other blood safety interventions. This approach is a better reflection of reality and prevents over-estimation of the benefits of interventions that avert adverse events.

  • The optimal blood safety portfolio framework can be used to consider the opportunity cost of all feasible combinations of interventions, overcoming a major limitation of traditional cost-effectiveness analysis methods. The framework is applicable for any set of diseases and interventions in any jurisdiction.

  • The method of integrating a machine learning model with a decision rule developed for the inter-donation interval analysis can be used for data-driven, individual-level policymaking in many settings.

Together, these projects advance the state of the art for blood safety policy assessment.

Several areas for future work remain. Moving forward, it is important to document best practices in both the methodology and reporting of blood safety policy assessment to establish standards that improve the rigor of decision-analytic modeling for blood safety and its applicability to policymaking. I envision a future in which health systems develop and maintain portfolio and surveillance models to continually assess the blood safety portfolio in light of current blood safety threats and adapt policies as epidemiologic conditions shift and new technologies become available. Toward this end, a key area for further research is to build on the methods developed in chapters 2-4 to develop blood safety portfolio assessment techniques that integrate sophisticated disease surveillance models. Another high-impact area for future efforts is to work with regulators and blood centers to further assess the benefits and barriers to implementation for personalizing inter-donation intervals. The level of acceptable risk is one open question that must be addressed before real-world implementation. Towards that end, one could perform preference elicitation with the medical directors of blood centers to understand beliefs around how iron-related risks to donors should be traded off against risks to the sufficiency of the blood supply. Future projects such as these can further inform critical blood safety policy decisions and ensure the efficient and effective use of limited blood safety resources.