Purpose: The purpose of this study is to assess empirical differences between CoI and QALY loss estimates and rankings across pathogens and pathogen-food pairs.
Methods: The study compares new QALY and CoI estimates and rankings for 14 foodborne pathogens and 168 pathogen-food pairs based on 2011 incidence estimates. It evaluates the influence of annual number of illnesses, hospitalizations and deaths on QALY and CoI rankings. It uses non-parametric statistical analysis to examine the relationships between rankings based on both integrated measures and on CDC incidence estimates. The study also examines the implications of data limitations on the completeness of QALY and CoI estimates and rankings.
Results: We find that existing research and data are sufficient to estimate both QALY loss and CoI due to acute illness with most foodborne pathogens, but that data on chronic sequelae are lacking for CoI. Despite this, we find QALY and CoI rankings to be highly correlated for pathogens, foods, and pathogen-food pairs. Both QALY and CoI rankings are driven by deaths and hospitalizations. Correlation between QALY and CoI measures falls considerably when focused on only the top 10-20 ranked pathogen-food pairs.
Significance: For overall rankings of all pathogen-food pairs, it makes little difference if rankings are based on CoI, QALY or deaths. As burden measures, CoI and QALYs each have meaningful strengths as well as empirical limitations. This study shows how these limitations affect estimates of the burden of foodborne disease in the U.S.