Zero Dollar Drug Copay program improves antidiabetic medication adherence and medication use patterns among Blue Cross and Blue Shield of Louisiana members with diabetes in Louisiana
Authors' conclusion
A zero-dollar co-pay pharmacy benefit improved antidiabetic medication adherence and increased medication use among BCBSLA members with diabetes.
Study context
- Population
- Continuously enrolled Blue Cross and Blue Shield of Louisiana (BCBSLA) members with diabetes, claims 2019–2021; mean age 48.8 (SD 12.5) years ZDC and 52.9 (SD 11.3) years controls
- Participants
- 7,603 participants
- Exposure
- Zero-dollar co-pay pharmacy benefit vs no ZDC coverage
- ZDCn = 3,045
- Controln = 4,558reference
- Outcome
- Antidiabetic medication adherence and use (all medications)
- Follow-up
- July 1, 2020, to December 31, 2021
Methodological detailspropensity score odds weights, weighted difference-in-differences with individual and time fixed effects
- Propensity score odds weights
- Weighted difference-in-differences with individual and time fixed effects
Main finding
As reported in the abstract
Difference-in-differences, monthly proportion of days covered (PDC)
4.4 percentage points
P < 0.001
ZDC
Difference-in-differences, monthly medication use
6.2 percentage points
P < 0.001
ZDC
Difference-in-differences, drug counts
0.090
P < 0.001
ZDC
Observational data: associations, not effects.
Further findings
| Outcome | Estimate | P value |
|---|---|---|
| ZDC-eligible medicationsZDC vs Control · increase with ZDC | difference-in-differences, PDC 5.4 percentage points | all p<0.001 |
| ZDC-eligible medicationsZDC vs Control · increase with ZDC | difference-in-differences, monthly use 7.6 percentage points | all p<0.001 |
| ZDC-eligible medicationsZDC vs Control · increase with ZDC | difference-in-differences, drug counts 0.074 | all p<0.001 |
Subgroups: pre-ZDC users, complex users, pre-ZDC non-users
- Improvements among pre-ZDC users and complex users, but not among pre-ZDC non-users
Original publication
Zero Dollar Drug Copay program improves antidiabetic medication adherence and medication use patterns among Blue Cross and Blue Shield of Louisiana members with diabetes in Louisiana. BMJ Open Diabetes Res Care. Published 20 January 2026. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →