Persistent bothersome urinary incontinence after radical prostatectomy can significantly impact quality of life. Men with post-prostatectomy incontinence (PPUI) receive standard investigation (SI) consisting of history, physical examination and cystoscopy. In complex cases of unclear etiology, they receive urodynamic (UDS) assessment, although this is not standard and there is little evidence regarding the impact of multichannel UDS on patient outcomes and costs in the management of PPUI. Our aim is to understand the impact of standard investigation (SI) vs SI and multichannel urodynamics (UDS) in men with post-prostatectomy urinary incontinence (PPUI) on quality adjusted life expectancy and to compare the cost-utility of treatment decisions. We hypothesize that pre-operative SI+UDS will improve the quality adjusted life expectancy for such men and the cost-utility of treatment decisions for PPUI as compared to SI alone.

We constructed a Markov model employing a two-dimensional (2D) Monte Carlo simulation using a lifetime horizon to compare the quality-adjusted life expectancy associated with the use of preoperative SI+UDS compared to SI. The primary assumption of the model was that UDS is always accurate at identifying the diagnosis, as there is no gold standard test to identify post-prostatectomy incontinence. We validated our model using the results of previous retrospective studies. We considered clinically important health states from immediately after investigation, initial treatment, commonly described complications, and failure of treatment. Transition probabilities and utilities for disease states were derived from a literature search of MEDLINE and expert consensus. Direct healthcare costs were derived from national and provincial health administrative data. Using the simulation results, we conducted a cost-utility analysis of preoperative SI+UDS compared to SI.

Men assessed with SI+UDS assessment were incontinent for 12.4 months less than those assessed with SI alone. Of the patient simulated, 25% fewer patients experienced medication failure. Patients treated with SI+UDS had an incremental cost utility ratio (ICUR) of $1110 per quality adjusted life year. SI+UDS was cost-effective with a willingness-to-pay (WTP) threshold set at $50 000 per quality adjusted life year (QALY) gained. In deterministic sensitivity analysis, the model was sensitive to patient age at treatment with SI+UDS becoming the dominant strategy after a threshold age of 70. In probabilistic sensitivity analysis, the model was robust to parameter uncertainty across 1 million iterations. The probability of UDS+SI being cost-effective was 83% at a WTP of $50,000/QALY.

This model-based cost-utility analysis suggests that SI+UDS is a economically favorable approach compared to SI in the pre-treatment workup of men with PPUI. Men assessed with SI+UDS assessment lived with incontinence 12.4 months less than those assessed with SI alone and experienced less medication failure. The addition of UDS assessment to SI was cost-effective 83% of the time in our model. The model suggests that patient age is important to consider in pre-treatment workup, and for men over 70 years, SI+UDS is always the most cost-effective approach. Limitations of this study include assumptions regarding the accuracy of UDS assessment, ignoring the development of patient comorbidity that could impact on treatment decisions, and focusing on single treatment modalities for stress (AUS) or urge (oral medication) incontinence.

In this cost-utility analysis model, multi-channel urodynamics with standard investigations is economically favourable compared to standard investigations alone in the pre-treatment assessment of men with post-prostatectomy incontinence. Future studies should be conducted to validate these findings in a real population.