Long-term cost-effectiveness of invasive urodynamic studies for overactive bladder in women

Objectives

To estimate the cost-effectiveness of using invasive urodynamic studies (UDS) in the management of women with refractory overactive bladder (OAB) symptoms using the results of the FUTURE trial.

Patients and Methods

The FUTURE study is the largest randomised controlled trial evaluating the clinical effectiveness of UDS with comprehensive clinical assessment (CCA) in this patient population compared to CCA only. We developed an economic model that replicates the 24-month results of FUTURE, then models the lifetime costs and quality-adjusted life-years (QALYs) using long-term studies of treatment outcomes.

Results

Over the patient cohort's lifetime the UDS plus CCA group is £1380 more costly and is associated with 0.002 fewer QALYs than the CCA only group, with only a 23.4% chance of being cost-effective at £20 000 per QALY gained. The sensitivity analysis shows that the results are robust to all changes except for the use of parameters based on the complete case analysis of the FUTURE trial. For the subgroup of patients with an initial diagnosis of mixed urinary incontinence, the UDS group gains more QALYs than the CCA group, albeit at a higher cost. The incremental cost-effectiveness ratio for UDS is £26 462, with a probability of being cost-effective of 45.3% at £20 000 per QALY gained and 53.8% at £30 000 per QALY gained.

Conclusion

The use of UDS in women with a diagnosis of OAB and whose condition is refractory to initial medical and conservative treatments is unlikely to be cost-effective when examined from a UK perspective and with a lifetime horizon. Despite having access to the FUTURE study data, the parameterisation of the model is limited by the current evidence base. An ongoing long-term follow-up study will help reduce these uncertainties.