A retrospective managed care claims data analysis of medication adherence to vaginal estrogen therapy: Implications for clinical practice

Objectives: This study sought to assess refill-based treatment duration and adherence to vaginal estrogen therapy (VET) in clinical practice and to compare treatment duration in women prescribed vaginal tablets (VT) or vaginal creams (VC) in clinical trials with that in clinical practice. Methods: Adults initiating VET between January and June 2004 were identified in 57 commercial health plans in the United States and followed for up to 10 months after treatment initiation. Treatment duration (Kaplan-Meier analysis) and adherence (medication possession ratio [MPR]) were examined for VC and VT cohorts and compared with a weighted average of treatment duration calculated for seven clinical trials identified in the literature. Results: Of 13,074 women (mean age 54 +/- 9.1 years) identified, patients on VT had significantly longer treatment duration compared with patients on VC (149.1 +/- 101.1 days vs. 91.6 +/- 30.0 days, p < 0.01). Among 5,599 patients receiving multiple prescriptions, higher treatment durations were observed for both VT-treated and VC-treated patients (198.5 +/- 82.4 days vs. 177.1 +/- 86.7 days, p < 0.01) compared with 165 days observed in clinical trials. Medication adherence (MPR >= 80%) was significantly higher among VT users compared with VC users (74% +/- 27% vs. 52% +/- 32%], p < 0.01); OR, 3.24, 95% CI 2.84-3.70). Conclusions: Duration of VET among patients receiving multiple prescriptions was longer in real-world clinical practice than in clinical trials. Newly treated patients initiating VT were more likely to continue treatment for longer periods and exhibited greater medication adherence than did those on VC.