Adherence to Oral Contraception in Women on Category X MedicationsAuthors: Amy Steinkellner, PharmD; William Chen, PhD, MPH; Shannon E. Denison, MA Published in the American Journal of Medicine, October 2010 Study in Brief: - The purpose of this study was to evaluate adherence to oral contraception in women of childbearing age who were also using Category X medications. Furthermore, we looked to identify risk factors that were linked to low adherence to oral contraception in the population. - The study was performed over an 18-month period and analyzed prescription claims of six million women ages 18-44 with claims for Category X medication and for oral contraception. - Adherence was evaluated based on mediation possession ratio (MPR), a measure of how much medication the patient has on hand at a given time. For the purposes of this study, an MPR of at least 95% was considered adherent. - Among the overall study population, 6% (146,758) of child bearing age women were taking one or more Category X medications. Within the Category X group, 18% (26,136) took an oral contraceptive medication, which was only slightly higher than the prevalence of oral contraception use within the general childbearing population (17%). - Approximately 40% of women taking Category X medications and oral contraception had refill patterns that suggested suboptimal adherence to their oral contraception and the study found no better adherence to oral contraception than in the general population. - Women who were prescribed a greater total number of medications were less likely to be adherent to their oral contraception and a majority of these women (68.9%) received five or more medications during the study period. -The study also found that women identified as an ethnic minority, those who were less educated and those who were taking a greater number of medications had a higher risk of non-adherence. View and DownloadFeatured Video |
 Amy Steinkellner, PharmDNational Practice LeaderMedco Health Solutions, Inc. Despite the availability of safe and effective contraception in the United States, 50 percent of all pregnancies in the United States are unplanned. Forty percent of unintended pregnancies occur in women who are using contraceptives and 90 percent of those are the result of inconsistent or incorrect use of contraception. While we know inconsistent or incorrect use of contraception is prevalent among the general childbearing population, I was particularly interested in seeing if this trend also held for those women who were also taking one or more Category X medications. My expectation and hope was that because of the potential risk of serious birth defects linked to those drugs, these women would be far more vigilant in their use of contraception in order to prevent an unintended pregnancy. Surprisingly, our study found that this may not be the case because, as the study shows, women on Category X medications are as likely to be non-adherent to oral contraception as other women in their age bracket. |