By Sandra Ripley Distelhorst
SAN FRANCISCO -- October 2, 2009 -- According to a prospective long-term community-based study presented here at the 39th Annual Meeting of the International Continence Society (ICS), only a small percentage of patients who are prescribed antimuscarinics to treat overactive bladder (OAB) symptoms continued treatment after 12 months and all patients had stopped taking antimuscarinic after 24 months.
The study, presented on October 1, highlights differences between clinical trials and real-world clinical practice, according to presenter Ramandeep Basra, MBBS, Guys and St. Thomas, NHS Foundation Trust, London, United Kingdom. "This is the first time we have looked at long-term data in a broad population representing typical patients seen in practice clinics."
The community-based study involved 251 women with OAB referred from primary care to 2 tertiary urogynaecology centres from May 2006 to August 2007.
Of the 251 women enrolled in the study, only 133 completed the 12-month follow-up; 107 patients dropped out of the study within the first 6 months. After 12 months, only 20% of patients were taking their prescribed medication, and no patients were taking an antimuscarinic after 24 months. Thirty study patients did not ever full their prescriptions.
All patients were given written and verbal information about the management of OAB. The first-line antimuscarinic agents used in the 2 clinics were solifenacin and extended release tolterodine. The subsequent choice of second- or third-line antimuscarinic agent was at the discretion of the prescribing physician (solifenacin, tolterodine, darifenacin, oxybutynin tablets or transdermal patches).
The mean number of antimuscarinic medication tried by patients ranged from 0 to 4 (mean 1.4). For those patients taking an antimuscarinic that allows for flexible dosing, 28% chose to increase their dose. Patients who tried more than 3 antimuscarinic agents reported a longer duration of medication use (mean duration of 29.6 weeks) than patients who used a single agent (mean duration 19.9 weeks).
Patients completed the Patient Perception of Bladder Condition scale (PPBC), a single-item questionnaire that provides an assessment of the patients' perception of their urinary symptoms, and the 33-item Kings Health Questionnaire (KHQ) that assesses health-related quality of life in patients with lower urinary tract dysfunction.
Greater severity of OAB symptoms as reported on the PPBC and KHQ was associated with use of a greater number of antimuscarinic agents, escalation of drug dose, and a longer duration of medication use. The study also found that eligibility for free medication did not affect the number of medications tried, the frequency of increasing dosages, or the persistence use of medication. Age and ethnicity were not associated with multiple medication switches, medication dose escalation, or a longer duration of medication use.
The study authors concluded that long-term persistence use of antimuscarinic medication in patients with OAB in clinical practice is lower than clinical studies would suggest. The percentage of patients requiring dose escalation in clinical practice is also significantly lower than that reported in clinical studies. A greater health-related quality of life impact from OAB is associated with the use of multiple antimuscarinic agents and a longer duration of medication use.
[Presentation title: Long-term Use of Antimuscarinic Medication in the Real World: Results of a Community-Based Prospective Study of Patients With Overactive Bladder. Abstract 160]
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