67th Annual Meeting Abstracts

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Overactive Bladder Medication Adherence When Medications Are Free To The Patients
Christine L Gray Sears¹, *Christa Lewis², *Kathleen Noel³, *Todd S Albright⁴, *John R Fischer^4
1Department of Urology, National Naval Medical Center, Bethesda, MD;²National Capitol Consortium Uniformed Services Residency in Obstetrics and Gynecology, Bethesda, MD;³Female Pelvic Medicine and Reconstructive Surgery, Walter Reed Army Medical Center, Washington, DC;⁴Female Pelvic Medicine and Reconstructive Surgery, Walter Reed Army Medical Center, Washington, DC

Introduction: In order to examine the effect of medication cost on medication compliance, we examined overactive bladder medication compliance in a healthcare system where patients do not pay for their medications.
Materials & Methods:
Pharmacy dispensing records were reviewed for antimuscarinic agents from January 2003 to December 2006 for the National Capital Region of the U.S. Military Health System. Medication non-persistence, switching, and adherence were examined. Kaplan Meier survival analysis was performed to compare medication persistence duration.
Results:
Overactive bladder medications were dispensed to 7,879 adults. Tolterodine extended release (4,716 prescriptions) and oxybutynin immediate release (2,003 prescriptions) were most commonly prescribed. The medication non-persistence rate was 35.1% (2,760/7,858). Of 5,098 subjects who refilled their prescriptions, 1,305 changed their medication or dosage at least once, for a medication switch rate of 25.6%. The overall median Medication Possession Ratio (MPR) was 0.82 for all subjects. Men had a significantly higher median MPR than women (0.86 vs. 0.81, p<0.001). However, among patients who obtained at least one refill, women stayed on medications longer than men (Median 606 days vs. 547 days, p=0.01). Patients on tolterodine extended release had a higher MPR than those on oxybutynin immediate release (0.89 vs. 0.68, p<0.01). There was no difference between any different extended release medications.
Conclusions:
In a health care system in which patients do not pay for medications, 35% of patients do not refill their prescription for overactive bladder medications. Other measures of medication compliance are higher than those published previously in systems with co-pays.

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