title: Association of copayment and socioeconomic status with hormonal contraceptive adherence in a female veteran population.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Veterans Affairs San Diego Healthcare System, San Diego, California; UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences, San Diego, California. Electronic address: rashid.kazerooni@va.gov.
authors.forename: Rashid
authors.initials: R
authors.lastname: Kazerooni
authors.affiliation: Veterans Affairs San Diego Healthcare System, San Diego, California; UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences, San Diego, California.
authors.forename: Khanh
authors.initials: K
authors.lastname: Vu
authors.affiliation: Veterans Affairs San Diego Healthcare System, San Diego, California; UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences, San Diego, California.
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Takizawa
authors.affiliation: Sharp HealthCare, San Diego, California.
authors.forename: Christine
authors.initials: C
authors.lastname: Broadhead
authors.affiliation: Department of Veteran Affairs, National Pharmacy Benefits Management Services, San Diego, California.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Morreale
mesh_terms: D000328:Adult; D002140:California; D003268:Contraception Behavior; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage / Q000191:economics*; D003669:Deductibles and Coinsurance / Q000191:economics*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009505:Nevada; D010349:Patient Compliance / Q000706:statistics & numerical data*; D012044:Regression Analysis; D012189:Retrospective Studies; D012923:Social Class; D012959:Socioeconomic Factors; D014728:Veterans / Q000523:psychology* / Q000706:statistics & numerical data
chemical_list: D003278:Contraceptives, Oral, Hormonal