Health Disparities
Using a target trial to estimate the causal effect of health technology on racial disparities Chloe Bennett* Chloe Bennett Rob Cavanaugh Louisa Smith
The burden of type 2 diabetes (T2D) disproportionately affects Black people, perpetuating health inequities. Continuous glucose monitors (CGM), which improve glycemic control and reduce complications, have the potential to mitigate racial disparities in T2D outcomes.
This ongoing study uses the target trials framework to estimate the causal effect of CGM initiation on racial inequities in hemoglobin A1c levels, a key indicator of diabetes control. We specified a target trial with the following design: non-Hispanic Black and White individuals with T2D and no prior CGM use are assigned to one of two treatment strategies: either initiate CGM use or continue with standard monitoring. Differences in A1c between the Black and White participants within each treatment arm after 1 year will quantify disparity in diabetes control.
This target trial is currently being emulated using data from the NIH All of Us Research Program, which includes electronic health records and surveys. Eligible participants are 18+ with self-reported T2D. Initial analyses found 17,507 participants with self-reported T2D; 9312 (53%) met eligibility criteria at least once. Eligible participants contributed a median of 5.66 years of data. The average A1c when participants first met eligibility criteria was 7.7% (Black participants) and 7.2% (White).
The emulation uses a repeated design: time zero begins every time A1c lab results are recorded, as long as eligible participants have no recorded use of a CGM within the year prior. Baseline confounding, including by baseline A1c level, is adjusted for via inverse-probability weighting to estimate an intention-to-treat effect. Pooling over all trials, we can estimate the difference in differences in A1c after 1 year between Black and White individuals across treatment and control groups. Results will be discussed in the context of the use of (1) health technology to address disparities and (2) the target trials framework to study them.