Our results suggest that routine preoperative MRSA screening and decolonization for orthopedic surgery patients would be a cost-effective and, in many circumstances, economically dominant strategy for a wide range of MRSA colonization prevalence (at least 1%) and decolonization success rates (at least 25%), from both the third-party payer and hospital perspectives. These findings may hold whether swab samples are obtained from 1 or 2 body sites, and they provide economic support for adopting such a strategy. The cost savings and health benefits of surveillance and decolonization seem to outweigh the cost of implementing such a strategy. In fact, the cost savings alone in many cases exceeds the cost of implementation. This is not a common finding, because most interventions require at least some net cost to realize health benefits.
Particularly compelling is the finding that decolonization does not have to be particularly effective for this strategy to be valuable. Short-term rates of decolonization success (long enough to cover the perioperative period) only have to be as high as 25% for the strategy to be cost-effective, substantially lower than many of the rates reported in the literature. A systematic review of MRSA eradication trials reported that a short course of mupirocin administered nasally was 90% effective 1 week after treatment and approximately 60% effective after a longer follow-up period, but additional studies are needed to ascertain the short-term effectiveness of assorted decolonization regimens.60,61
Combining this study with our previously published study of simulated vascular surgery patients, we have now revealed that routine preoperative surveillance and decolonization may provide substantial economic value in 2 different large populations of surgical patients.18,62
Although the vascular and orthopedic surgery populations are similar in many ways (eg, patients tend to be older, with a median age in the mid-60s, and have comorbid conditions; and many procedures are scheduled electively rather than emergently), there are important differences.18
As may be expected, vascular insufficiency, which can predispose patients to develop postoperative infections, is more common among vascular surgery patients. Vascular surgical procedures create a direct route of entry to the bloodstream, potentially allowing bacterial contamination to rapidly lead to systemic complications, whereas orthopedic surgical procedures, although invasive, mainly involve soft tissue, osteochondral, and articular spaces in which bacterial contamination tends to remain more localized. The surgical materials and equipment are also quite different, with vascular procedures involving the use of catheters, grafts, and stents and orthopedic procedures involving the use of drills, saws, and hardware. Our model also reflected other key differences, such as the postoperative length of stay and the rate and type of surgical revisions.
The evidence does not yet suggest that MRSA screening should be applied to all preoperative surgical patient populations. Such a strategy may not be as advantageous for younger and healthier surgical patient populations (eg, cosmetic surgery) or for patients undergoing less invasive procedures (eg, ophthalmologic surgery). Researchers undertaking future studies may want to investigate the cost-effectiveness of MRSA screening and decolonization among surgical patient populations (eg, urological or gastrointestinal surgery) for which the economic value may be more equivocal.
Our analyses may underestimate the economic value of MRSA screening for several reasons. First, we endeavored to remain conservative about the benefits of MRSA surveillance when constructing the model. We deliberately elected to incorporate high screening and decolonization costs, to include only the most common complications of postoperative MRSA infections, and to use the least expensive diagnostic and treatment procedures for each clinical condition. Second, the model did not account for transmission of MRSA between carriers and noncarriers. Third, our model accounted only for infections caused by MRSA. Accounting for the additional health and financial outcomes due to infection by methicillin-susceptible strains of S. aureus would increase the economic value of surveillance. Fourth, decreasing the incidence of MRSA infections could reduce antibiotic use and decrease selection pressure for the evolvement of antibiotic resistance. Fifth, the model did not quantify the value of surveillance information (eg, colonization prevalence and infection incidence) gleaned from a structured MRSA surveillance and decolonization program.
Our findings were limited by the fact that all computer simulation models are simplifications of real life and cannot represent all possible MRSA colonization and infection outcomes in the highly heterogeneous orthopedic surgery patient population. The data inputs for our model came from different studies of varying quality but represent the best approximations of their respective values that were available to us. The findings of this model may not be applicable to patients undergoing emergency orthopedic surgery, because the urgency of treatment obviates screening.
In conclusion, the results of our model provide strong economic support for MRSA screening and decolonization in patients preparing to undergo orthopedic surgical procedures. Results were strongly cost-effective (ICER less than $10,000 per QALY) or dominant from both the third-party payer and hospital perspectives for a variety of MRSA colonization prevalence rates (1%–30%), testing and decolonization costs ($300 or less), and decolonization success rates (25%–100%). Preventing the substantial morbidity and mortality associated with MRSA infections can lead to improved patient outcomes and decreased resource use. Clinical practitioners, infection control specialists, hospital administrators, third-party payers, and other decision makers can compare the inputs and assumptions of our model and the findings of our analyses with their local circumstances when deciding whether to implement routine preoperative MRSA testing for orthopedic surgical patients.