Improved Methods to Understand the Impact of Tobacco Use on the Distribution of Healthcare Expenditures

Associate Adjunct Professor, UCSF School of Dentistry

Accurate assessment of the impact of tobacco use on health outcomes and healthcare expenditures is critical in regulatory science to assist policy makers to promulgate rational policies. However, confounding is a potential problem for assessments based on observational studies. Recently, modern analytic methods that use causal modeling have been successfully applied to address confounding inherent in observational research.
In studies of the impact of tobacco use on healthcare expenditures and health outcomes, these outcomes variables are typically skewed right , because many individuals may not yet have disease or related healthcare expenditures, while a small number may experience severe disease or extremely large expenditures. Different approaches have been developed to model such outcomes with excess zeroes. However, most methods consider the overall average effect between groups, not how the full distribution differs between groups (such as tobacco users and non-users) or whether outcome distributions differ among tobacco products, which have the same average effect but different implications for affected individuals.
Therefore, we propose two specific aims in this project. In Aim 1, we will develop new methods to evaluate the impact of tobacco use on the distribution of tobacco related cost outcomes with excess zeroes when many possible confounders require adjustment, without parametric assumptions on the outcome distribution. In Aim 2, we will evaluate whether different tobacco product uses change the distributions of healthcare expenditures differentially among adult tobacco users (>18 years) even when average healthcare expenditures are about the same.
Compared to just knowing average effects, knowing the impact of tobacco use on the full distribution of healthcare expenditures would enable policy makers to capture a more complete picture and then tailor programs or policies to control tobacco for individual or subgroup needs.