Association of copayment and socioeconomic status with hormonal contraceptive adherence in a female veteran population.

Background: There are limited studies available analyzing association between copayment and hormonal contraception adherence. The study was conducted to investigate the association between copayment status and hormonal contraceptive adherence in a female veteran population when stratified by socioeconomic status.

Methods: This 4-year, retrospective, cohort study of women Veterans from the Veterans Integrated Service Network 22, a network of Veterans Affairs facilities that includes Southern California and Nevada, included patients who received a new hormonal contraceptive prescription between October 1, 2008, and September 30, 2012. Patients were split into five quintiles (one having the lowest income and five the highest) dependent on zip code-based median annual household income from the 2007-2011 American Community Survey data. Medication possession ratio difference of copayment versus no copayment group for each respective quintile was the primary outcome. Analysis was done using multiple linear regression models.

Results: A total of 3,622 patients met the inclusion criteria and were included in the analysis. Over the entire population, copayment was significantly associated with reduced adherence (-0.034; 95% confidence interval [CI], -0.06 to -0.008). Patients in the highest socioeconomic group, quintile five, had the largest reduction in adherence associated with having a copayment (-0.073; 95% CI, -0.129 to -0.017). Patients in the other four quintiles saw varying levels of decreased adherence respectively, although the differences did not achieve statistical significance.

Conclusion: The association between adherence and copayment status varied by socioeconomic status. Our findings suggest that even affluent patients may be discouraged from adherence when subject to a copayment. If larger studies substantiate these findings, consideration should be given to a policy that exempts women veterans from copayments for hormonal contraceptives.