ESTIMATING THE EFFECT OF TOTAL JOINT REPLACEMENT WAIT TIME STRATEGIES IN ONTARIO USING SIMULATION MODELING
Lauren E. Cipriano, BSc, BA, Massachusetts General Hospital, Boston, MA, Bert M. Chesworth, PhD, University of Western Ontario, London, ON, Canada, Chris K. Anderson, PhD, Cornell University, Ithaca, NY, and Gregory S. Zaric, PhD, University of Western Ontario, London, ON, Canada.
Purpose The median wait time for total hip and knee joint replacement in Ontario is greater than 6 months and there is wide variation in the wait times for surgery across the province. An aging population will create additional demand for joint replacement surgery over the next 10 years. Several clinical organizations have suggested that it is inappropriate to wait longer than 6 months for total hip and knee joint replacement. Methods We developed a simulation model to estimate future wait times. We used the simulation to determine the distribution of wait times that would be experienced if different wait list management strategies were implemented. We evaluated the use of formal clinical prioritization compared to first-come-first serve wait list management. We considered the impact on wait times of wait time guarantees, centralized wait list management, changing the method of allocating surgeries across regions, reducing surgical demand through prevention, and diverting patients to other jurisdictions for surgery. Results Clinically prioritizing patients relative to selecting patients for surgery on a first-come-first-served basis does not change the average wait time across all patients but does affect the distribution of wait times for patient sub-groups. Wait time guarantees that applied only to high priority patients reduced wait times for high priority patients and increased wait times for low priority patients. Conversely, wait time guarantees that applied to all patients, increased wait times for high priority patients and decreased wait times for low priority patients. Centralizing wait list management improved efficiency and increased equity in waiting across regions within the province. Allocating surgeries using a proxy for surgical need in each region resulted in a more efficient distribution of surgeries and a greater long-term reduction in wait times. If the annual compound rate of growth in surgical capacity is less than 10%, then demand projections must be reduced by at least 15% in order to reduce wait times within 10 years. Discussion The incremental change in wait times that would result from implementation of several different wait list management options have been demonstrated. This information can be combined with clinical knowledge of outcomes as a function of wait times and the cost of each alternative to determine which strategies may be cost effective in addition to providing wait time reductions.