Abstract S6-4: Association between Prescription Co-Payment Amount and Compliance with Adjuvant Aromatase Inhibitor Therapy in Women with Early Stage Breast Cancer

Abstract

Abstract Background: Non-adherence to adjuvant hormonal therapy among women with breast cancer is common, but little is known about how financial factors influence it. We investigated the relationship between prescription co-payment amount and compliance with adjuvant aromatase inhibitors (AI) therapy. Patients and Methods: Using de-identified, integrated pharmacy and medical claim database at Medco Health Solutions, Inc. women >50 years old on AIs for early breast cancer with at least 2 mail order prescription refills between 1/1/07 and 12/31/08 were identified. All data were pooled prior to the analysis. Variables that were evaluated included medical and demographic information, household income, number of other prescriptions, diagnostic codes, prescription refill dates, provider type and co-payment amounts. Age was classified as <63 or ≥63 to distinguish patients ever covered by Medicare. Copayment amount was categorized as <$30, between $30 and $89.99, and ≥$90. Non-persistence was defined as prescription supply gap of 45 days with no subsequent refill. Non-adherence was defined as a medication possession ratio ≥80% of eligible days. Logistic regressions and Cox proportional hazards modeling were used. Results: Of 8110 women age 50-62 years (mean=59.1), 1721(21.2%) were non-persistent and of those who continued, 863(10.3%) were non-adherent over the 2 year period. Among 14,050 women ≥63 years (mean=74.9), 3476(24.7%) were non-persistent and of those who continued, 1248(8.9%) were non-adherent. Ninety day co-payments ranged from $0 to $893.49. In a multivariate analysis, non-persistence (ever/never) in both age groups was associated with older age, having a primary care physician write the prescription, and higher number of co-prescriptions. Similar results were seen with non-adherence. Compared to a copayment of <$30, a 90 day copayment of $30-$89.99 was associated with time to non-persistence in women ≥63 (HR 1.34, 95%CI 1.24-1.46) but not among women <63, while a copayment ≥$90 was associated with time to non-persistence both in women <63 (HR 1.26, 95%CI 1.09–1.38) and women ≥63 (HR 1.33, 95%CI 1.22–1.46). Conclusions: We found that a higher prescription co-payment was associated with both early discontinuation and non-adherence to AIs. This relationship was stronger for older women. Because hormone therapy non-compliance is associated with worse survival outcomes, future public policy efforts should be directed towards reducing financial constraints as a means of increasing the use of these life-saving medications. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S6-4.