Intolerance and affordability affect compliance in treating overactive bladder with solifenacin

Michelle M.Y. Lai1,2, Chok L. Lui3, Charles A. Inderjeeth1 1 Department of Rehabilitation and Aged Care, Sir Charles Gairdner Hospital, Perth, Western Australia2 Department of Geriatric Medicine, Royal Perth Hospital, Perth, Western Australia3 Department of Geriatric Medicine, Swan Kalamunda Health Service, Perth, Western Australia

Results

79 patients were considered candidates for pharmacological management. Solifenacin was prescribed in 16 patients, including 8 who failed to tolerate or improve with oxybutynin or amitriptyline in primary care.

Mean age was 81 years (SD=10) and 93.8% were women. All were Caucasians and community dwelling. None had diagnosis of dementia.

Compliance and cost savings

At 1 year, excluding 2 patients who were deceased, only 4 (28.6 %) patients continued to take solifenacin and one of them achieved continence indoors.

Side effects were reported in 5 patients but 2 continued the medication with tolerable dry mouth and slowness in thought. 2 patients did not remember solifenacin was prescribed. Affordability was the reason for poor compliance in 2 patients while the rest provided no reason.

There was no sustained reduction in pads usage compared to that at baseline or 8 weeks. A lack of cost savings in overall continence management (continence products and medication) was observed in the 4 patients who remained on solifenacin.

References

1. Dorosheyenko O, Fuhr U. Clinical pharmacokinetics and pharmacodynamics of solifenacin. Clinical Pharmacokinetics. 2009:48(5):281-302.

2. Wagg A, Wyndaele JJ, Sieber P. Efficacy and tolerability of solifenacin in elderly subjects with overactive bladder syndrome: a pooled analysis. Am J Geriatr Pharmacother. 2006 Mar;4(1):14-24.

3. Australian Government. Medicare Australia. Pharmaceutical Benefits Scheme. Available from URL: http://www.medicareaustralia.gov.au/provider/pbs/index.jsp (accessed on 5 January 2010).

This poster is presented at ANZSGM annual scientific meeting 2010.

Solifenacin is gaining popularity among geriatric clinics in Australia. It is considered as an alternative to lessen symptom of urinary urgency with or without incontinence in patients who are intolerant to conventional anti-cholinergics such as oxybutynin [1].

We report on a case series of older patients with overactive bladder treated with this newer anti-muscurinic agent. The ethics committee at Sir Charles Gairdner Hospital approved this study.

We reviewed bladder diaries of patients who received solifenacin in 2 geriatric continence clinics in WA metropolitan area in 2008. Patients were contacted by phone after 1 year. Efficacy endpoints were tested by paired t-test using SPSS.

Short-term efficacy

At 4 weeks, significant improvement was observed in all parameters in standard 3-day bladder diaries (all p<0.05). Efficacy was sustained at 8 weeks (all p<0.05) Only 2 patients required 10mg due to inadequate response at low dose. They were then discharged to primary care. (table 1)

Table 1. mean change from baseline for patients on solifenacin

Parameters Baseline At 4 weeks (n=11) At 8 weeks (n=8)

(n=16)Mean (SE)

Mean difference

p-value* Mean (SE)

Mean difference

p-value*

Micturition frequency per day

10.93 (1.34)7.73

(0.70)3.20 p<0.05

8.14 (0.74)

2.79 p<0.05

Urgency episodes per day

7.07 (0.89)4.50

(1.01)2.57 p<0.001

4.00 (1.00)

3.07 p<.0.05

Incontinence episodes per day

4.07 (0.44)1.73

(0.43)2.34 p<0.005

1.00 (0.22)

3.07 p=0.01

Pad use per week 22.64 (2.13)15.62 (3.26)

7.02 p<0.0512.80

(4.97)9.84 p<0.05

*by paired t-test

Discussion

Solifenacin has proven efficacy and safety in the elderly in previous studies[2]. However, telephone follow up of our patients at 1 year revealed that persistence was poor in the real world setting.

Discontinuation rate due to side effects (18.8%) in our patients was higher than expected. In a pooled analysis from 4 studies, although discontinuation rate in patients over 65 years old (mean age = 72) appeared to be higher at 10mg daily, the rate at 5mg was comparable to placebo (9.3%, vs. 4.7 and 5.5%, respectively) [2].

Affordability and cost were also important to 4 patients. Two dropped out for this reason, although they were willing to pay initially, knowing the drug was not listed under Pharmaceutical Benefits Scheme (PBS) [3]. This is another example that patients’ perspective is sometimes more important than clinical efficacy of a medication.

Conclusion

Despite short term efficacy of solifenacin was evident in our patients, compliance was poor after 1 year of use.

Government of Western AustraliaDepartment of HealthNorth Metropolitan Area Health Service