Exploring the Relationship Between Medication Adherence and Diabetes Disparities among Hispanic Patients in a Large...

Area of Science:

• Diabetes Management
• Health Disparities Research
• Clinical Informatics

Background:

• Sub-optimal hemoglobin A1c (HbA1c) control contributes to disparities in diabetes outcomes for Hispanic patients.
• Differences in medication adherence are a potential factor contributing to racial/ethnic variations in HbA1c levels.

Purpose of the Study:

• To investigate the association between medication adherence and disparities in HbA1c levels among Hispanic patients compared to other racial/ethnic groups within the University of California Health System (UC Health).

Main Methods:

• A cross-sectional analysis utilized clinical, administrative, and prescription dispensing data from UC Health electronic health records (January-December 2021).
• Linear regression models (LRMs) assessed the relationship between medication adherence (proportion of days covered - PDC) and HbA1c levels, adjusting for race/ethnicity.
• The study included 27,542 patients aged 18-75, reporting Asian, Hispanic, or White race/ethnicity, with a diabetes diagnosis or medication prescription.

Main Results:

• In models excluding medication adherence, Hispanic ethnicity showed a positive association with HbA1c levels (β=0.31, p<0.001).
• When medication adherence (PDC) was included, it was negatively associated with HbA1c levels (β=-0.18, p<0.001).
• Crucially, the positive association between Hispanic ethnicity and HbA1c levels remained unchanged (β=0.31, p<0.001), indicating adherence did not explain the disparity.

Conclusions:

• Medication adherence, measured by PDC, did not account for the observed disparities in HbA1c levels among Hispanic patients.
• These findings highlight the need to explore other factors beyond medication adherence that influence the relationship between Hispanic ethnicity and HbA1c levels in academic medical centers.