501. Medicare Reimbursement across the Continuum of Care Attributable to Surgical Site Infection following Primary Total Hip and Knee Replacement: a Retrospective Cohort Study using Administrative Data
Session: Poster Abstract Session: Surgical Site Infections
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Background: Previous estimates of the financial burden of surgical site infection (SSI) following hip and knee replacement focus on inpatient facility charges. This analysis aimed to estimate Medicare reimbursement across the continuum of covered Medicare services attributable to SSI following primary hip or knee replacement.

Methods: Medicare beneficiaries who underwent elective, unilateral, primary total hip or primary knee replacements, for which claims were submitted in 2004, were identified from a 5% sample of all enrollees. The study cohort consisted of fee-for-service Medicare beneficiaries with continuous coverage of parts A and B, aged ≥65 years, and without evidence of SSI at or prior to the time of surgery. Inpatient, outpatient, skilled nursing facility, home health, and non-institutional provider claims between 2001 and 2008 were utilized. Beneficiaries were considered diagnosed with an SSI if ICD-9-CM diagnosis code 996.66 (infection and inflammation reaction due to internal joint prosthesis) was present at least once on an inpatient claim within 365 days after procedure. To assess Medicare reimbursement attributable to SSI, four-year reimbursement was modeled as a function of SSI status, age, sex, race, comorbidity score, reimbursements in the two years before and during the hospitalization in which the procedure was performed, and length of follow up using a generalized linear model with a natural log-link and gamma distribution for each procedure type. The method of recycled predictions was used to estimate attributable reimbursement point estimates in US dollars.

Results: Thirty-three of 3774 and 90 of 7642 beneficiaries with hip and knee replacements, respectively, had an SSI diagnosis. Over the four years following the procedure, total reimbursement was 2.6 times (1.9-3.5, P<.0001) higher following hip and 2.3 times (2.0-2.8, P<.0001) higher following knee replacement among beneficiaries with SSI compared with those without SSI. Medicare reimbursement attributable to SSI was $67,077 for hip and $56,771 for knee replacement.

Conclusion: Estimated reimbursement attributable to SSI in four-years following elective primary total hip and knee replacement exceeded $50,000 per SSI. The development of an SSI following primary total hip or knee replacement appears to be costly to the Medicare program.

Sarah H. Yi, PhD1, James Baggs, PhD1, Steven D. Culler, PhD1,2, Sandra I. Berrios-Torres, MD1 and John A. Jernigan, MD, MS3, (1)Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, (2)Rollins School of Public Heath, Emory University, Atlanta, GA, (3)Division Of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA


S. H. Yi, None

J. Baggs, None

S. D. Culler, None

S. I. Berrios-Torres, None

J. A. Jernigan, None

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