Cost-Effectiveness of Open Repair of Abdominal Aortic Aneurysms with a Novel Perioperative Protocol

Background: In 2015, a novel perioperative protocol (nPOP), comprising of 19 evidence-based interventions, was adopted as a standard practice for open repair of abdominal aortic aneurysms (AAA) at the Humanitas Clinical and Research Center (Milan, Italy). Its implementation translated into lower complication rates, faster ambulation and return of bowel function, better nausea/vomiting and pain control, and, consequently, a shorter length of hospital stay. Because value of a patient's care cycle can be defined as clinical outcomes relative to costs, we aimed to analyze the cost-effectiveness of nPOP compared to the previously implemented protocols.

Methods: Three groups were identified and retrospectively analyzed: (A) 66 patients (September 2007 to March 2009) treated according to the traditional protocol; (B) 225 patients (April 2009 to March 2015) treated in line with a transitional protocol, incorporating 5 perioperative interventions; and (C) 103 patients (April 2015 to February 2019) treated according to nPOP. For each group a monetary value of required clinical resources and the actual total cost per patient from admission to discharge were determined. The following were analyzed (including nurse and anesthesiologist time): diagnostic tests, medications, materials, operating time, surgical team time, blood transfusion, ward stay, and intensive care unit stay. Two indicators of effectiveness were determined based on the postoperative outcomes: complication-free incidents and relative shortening of hospitalization time. A cost (€) of an improvement in effectiveness (%) was calculated.

Results: Alongside enhancement of clinical outcomes, nPOP constituted the cheapest approach. It consumed the least human and material resources, resulting in the direct reduction in the overall clinical cost per patient. The length-of-stay variable provided the largest reduction in total costs. The actual total clinical cost per patient in Group C was 26% lower than in Group A (4,437€ vs. 6,005€) and 39% lower than in Group B (4,437€ vs. 7,305€). Every unit of enhancement of clinical outcomes was 2.43 times more expensive for the traditional protocol and 2.23 times more costly for the transitional protocol compared to nPOP, making it the most cost-effective.

Conclusions: The nPOP for AAA open repair is not inferior to other perioperative protocols while allowing for efficient utilization of limited hospital resources, thus creating a high social value. The proposed methods for cost-effectiveness analysis are easily reproducible and therefore can be applied in future projects ranging from a micro- to a macro-economic scale.