Study design, materials and methods
In order to determine the most cost-effective surgical strategy, we used TreeAge Pro® software to construct a decision model tree comparing the cost-effectiveness of four surgical options: HP with SS (HP-SS), HP with US (HP-US), VH with SS (VH-SS) and VH with US (VH-US). We modeled a population of healthy women undergoing surgery with a model time horizon of 1 year. Recurrence rates, repeat surgery for surgical failures and complication rates associated with each surgery were modeled. Parameter values were modeled using published Health Utility Indices included baseline uterine prolapse (0.83), repeat surgery for recurrent prolapse (0.75), GU injury (0.75), dyspareunia (0.90), neuropathy (0.66), and transfusion (0.76). Cost data reflects Stanford Hospital costs billed to insurance providers, including HP-SS $41,637.33, HP-US $41,466.00, VH-SS $50,258.00, and VH-US $50,258.00. Cost-effectiveness was defined as an incremental cost-effectiveness ratio (ICER) of < $50,000 per quality-adjusted life year (QALY). Strategies were considered “dominated” if they were both less effective and more expensive than another strategy. Base-case, threshold and 2-way sensitivity analyses were performed.
HP-SS was the most cost-effective strategy, where incremental cost of HP-US was $1,096.21, VH-SS was $7,681.34 and VH-US was $8,775.98 (Table 1). With similar QALY measures between surgical options, the VH-SS and VH-US were dominated strategies (Figure 1A). VH strategies are cost-effective when cost of HP-SS is > $52,500 and HP-US is > $49,500. VH strategies also become cost-effective when recurrence rates of hysteropexy is > 30% with a repeat surgery rate >60%, or with recurrence >40% and repeat surgery rate >40% (Figure 1B).
Interpretation of results
In our model, sacrospinous hysteropexy was the most cost-effective strategy followed by uterosacral hysteropexy, vaginal hysterectomy with sacrospinous ligament fixation and then vaginal hysterectomy with uterosacral ligament suspension. With similar QALY measures between surgical options, both vaginal hysterectomy with apical suspension surgeries were dominated strategies. When we varied the costs of the different strategies, vaginal hysterectomy strategies became the most cost-effective option when the cost of sacrospinous hysteropexy is > $52,500 and uterosacral hysteropexy is > $49,500. Of note vaginal hysterectomy with sacrospinous ligament suspension was more cost-effective than vaginal hysterectomy with uterosacral ligament suspension. The likely driver for a more expensive uterosacral ligament procedure is the 1-3% risk of GU injury which can lead to a repeat surgery costing ~$50,000. Our results also suggest that even if the probability of recurrent uterine prolapse is 15% and all these patients undergo a second surgery, sacrospinous hysteropexy will remain the optimal cost-effective strategy. However, as the probability of recurrent uterine prolapse and the probability of repeat surgery increases, vaginal hysteropexy no longer remains cost-effective.