Division of Clinical Research, Department of Obstetrics and Gynecology, Washington University, St Louis School of Medicine, St Louis, MO 63110, USA.
Contraception. 2011 Apr;83(4):340-5. doi: 10.1016/j.contraception.2010.08.003. Epub 2010 Sep 17.
We examined prescription adherence rates by contraceptive method among women who used oral contraceptive pills (OCP), transdermal patch or vaginal ring.
Women in the St. Louis area were provided their choice of OCP, patch or ring at no cost and followed for 18 months. Time between monthly refills was obtained from pharmacy data and analyzed as a marker of adherence. Risk factors for initial nonadherence were estimated using Cox proportional hazards; predictors for repeated nonadherence were analyzed using Poisson regression with robust error variance.
Overall, 619 participants filled 6435 contraceptive prescriptions with a median of 10 refills per participant. Only 30% of women (n = 187) obtained all refills on time. In the time-to-failure analysis, use of vaginal ring and increased parity were predictors of early nonadherence (p < .05). In the multivariable analysis, use of the vaginal ring and history of abortion were risk factors for repeated nonadherence (p < .01).
Even with financial barriers removed, pharmacy data show that many women inconsistently refill their contraception and may be at risk for unintended pregnancy.
我们研究了使用口服避孕药（OCP）、透皮贴剂或阴道环的女性的避孕方法的处方依从率。
圣路易斯地区的女性可以免费选择 OCP、贴剂或环，并随访 18 个月。从药房数据中获得每月补充之间的时间，并将其分析为依从性的标志物。使用 Cox 比例风险估计初始不依从的危险因素；使用具有稳健误差方差的 Poisson 回归分析重复不依从的预测因素。
总体而言，619 名参与者共填写了 6435 份避孕处方，中位数为每位参与者 10 次补充。只有 30%的女性（n=187）按时获得了所有补充。在失效时间分析中，使用阴道环和更高的产次是早期不依从的预测因素（p<.05）。在多变量分析中，使用阴道环和堕胎史是重复不依从的危险因素（p<.01）。
即使消除了经济障碍，药房数据仍显示许多女性不规律地补充避孕措施，可能有意外怀孕的风险。
