A cost-effectiveness analysis of delayed sphincteroplasty for anal sphincter injury

Objective  Anal-sphincter injury may result in faecal incontinence. Sphincteroplasty is usually performed as a primary (immediate) procedure. Delayed sphincteroplasty (DS) can be performed if there is significant trauma or soiling, if the primary procedure has failed, and if the injury was not recognized initially. This study aimed to determine the cost to patient and health service in the event a DS is performed.
Method  Patients with anal-sphincter-injury who underwent primary sphincteroplasty (PS)/DS were identified from the published literature (primary, n  = 103; delayed, n  = 777) using Medline, Embase, Ovid and Cochrane databases for studies published between 1976 and 2006. Studies included described at least one of the measured outcomes – probability of functional success/failure and quality of life (QOL). An economic model was constructed and decision analysis performed using a decision tree based on a Markov process. Main outcomes were quality-adjusted-life-years (QALYs) gained from each strategy, costs incurred and incremental cost-effectiveness ratio (ICER) over a 10- and 15-year time horizon.
Results  Over 10 years, primary sphincteroplasty (PS) produced a gain of 5.72 QALYs for an estimated £2750, giving an ICER of £487 per QALY. DS produced a gain of 3.73 QALYs for a cost of £2667, giving an ICER of £719 per QALY. Both procedures fell below the £10 000 per QALY willingness-to-pay threshold, but PS produced the highest QALYs. Both procedures performed poorly beyond the 10-year mark.
Conclusion  If DS has to be performed, the resultant cost is greater with concurrently lower QALYs gained. Successful PS substantially improves QOL and reduces overall cost-of-treatment.