Applying the Target Study Conceptual Model to Measure Racial and Ethnic Disparities in Hypertension Treatment Intensification

BACKGROUND: This tutorial paper demonstrates the application of a conceptual model to measure racial and ethnic disparities in treatment intensification among adults with hypertension consistent with the Institute of Medicine (IOM) definition. The IOM defines disparity as differences in health care quality that are not due to access-related factors, clinical needs, preferences, and appropriateness of intervention (referred to as allowable covariates). METHODS: We used a conceptual model called the Target Study to estimate annual disparities in the probability of treatment intensification between Black and White patients seen at primary care clinics within a large healthcare system in the Mid-Atlantic region from 2018 to 2022, using electronic medical record data. We emulated the specified target study through an appropriate study design and the use of inverse probability weighting to balance allowable covariates while measuring disparities. RESULTS: Unadjusted analyses showed a higher percentage of treatment intensification for Black patients compared with White patients, with annual differences ranging from 2 to 4 percentage points. For example, in 2020, the unadjusted difference was three percentage points (95% confidence interval: 1%, 5%). After adjusting for allowable covariates via the emulated target study, Black patients had consistently lower percentages of treatment intensification by 3-4 percentage points each year. For example, in 2020, the adjusted disparity was -3 percentage points (95% confidence interval: -4%, -1%). CONCLUSIONS: The Target Study can implement the IOM definition for measuring disparities in health care. Future research should explore its application across different populations to better understand and address health disparities.