Analytical approach:
A decision-tree model was used to combine the data from systematic reviews and other published sources. The analysis had a one-year time horizon. The authors stated that it took the perspective of the UK NHS.
Effectiveness data:
The effectiveness data were from a published systematic review and meta-analysis (Chapple, et al. 2008, see 'Other Publications of Related Interest' below for bibliographic details). Another systematic review and meta-analysis provided the baseline data for urinary frequency, urgency, and incontinence. The persistence data for each drug were from the Information Management System Database. The percentage of patients stopping or switching from fesoterodine was based on data for tolterodine extended release, in the absence of other data. Expert opinion was used for the proportion of patients who stopped or switched treatment due to non-adherence. The main clinical effectiveness estimate was the treatment success. Success for a 24-hour period, for urgency was defined as no urge episodes, for frequency was defined as eight or fewer voids, and for incontinence was defined as no incontinence episodes.
Monetary benefit and utility valuations:
The health utilities were from published literature and were measured using the European Quality of life (EQ-5D) questionnaire to assess the impact on quality of life of a reduction in voids and incontinence episodes. The utilities for a partial response were assumed to be the mid-point between the baseline utility and the utility for a full response. Patients who stopped or switched treatments returned to their baseline utility level.
Measure of benefit:
The primary measure of benefit was quality-adjusted life-years (QALYs).
Cost data:
The cost categories included the drugs, GP visits, and out-patient visits for urology and gynaecology. The drug costs were from the British National Formulary and other unit costs were from standard sources. The cost of adverse events or the additional costs incurred by either adhering or discontinuing treatment were not included. It was assumed that patients who discontinued treatment incurred no further costs. The resource use was based on expert opinion. All costs were reported in 2007 to 2008 UK pounds sterling (£).
Analysis of uncertainty:
The uncertainty was explored in both one-way and probabilistic sensitivity analyses. The probabilistic sensitivity analysis used 1,000 Monte Carlo simulations. The health utilities and costs were varied by 20% in the one-way sensitivity analysis only. Any variable that was excluded from the probabilistic sensitivity analysis and was found to be a driver of the results was varied in a threshold analysis.