320. Variation in Use of Chronic Antibiotic Suppression (CAS) for Treatment of Staphylococcus aureus Prosthetic Joint Infection (PJI)

Background The Infectious Diseases Society of America (IDSA) guidelines observed that prescribing CAS for treatment of PJI is an unresolved issue. We aimed to characterize variation in the use of CAS while accounting for patient-level factors to identify targets for antimicrobial stewardship in the Veterans Affairs system. Methods A retrospective cohort study was conducted using data on veterans with a diagnosis of S. aureus PJI between 2003 and 2015. Patients managed with debridement, one-stage exchange (OSE), or two-stage exchange (TSE) were included. Differences in characteristics between any CAS and no CAS treatment (None) were determined by the Mann–Whitney U test for continuous variables and Fisher’s exact test for dichotomous variables. Generalized linear-mixed models were used to calculate the risk standardized measure (observed to expected [O/E] ratio) of a hospital’s CAS use. Results Nine hundred forty-four (75%), 310 (25%), and 11 (<1%) were managed with debridement, TSE, and OSE, respectively, among the 1,265 included patients. CAS was prescribed in 80% of debridement patients, 49% of TSE patients, and 100% of OSE patients. Patient factors associated with CAS use were different for debridement and TSE (table). Risk adjusted models demonstrated greater variability among facilities using CAS after TSE compared with debridement and the overall cohort (figure). Conclusion There is substantial variation in the use of CAS by patient characteristics for S. aureus PJI across the VHA system. This variation differs between debridement and TSE surgery patients. Further research is warranted to guide CAS recommendations. Table: Characteristics for Overall Cohort and by Type of Surgery Overall Debridement TSE Patient factors different between any vs. none CAS groups Site of PJI (P = 0.001) Age (P = 0.03) Body mass index (P = 0.008) Psychosis (P = 0.02) Coagulopathy (P = 0.03) Serum creatinine# (P = 0.04) Erythrocyte sedimentation rate# (P = 0.0003) Obesity (P = 0.007) – Serum creatinine# (P = 0.0002) Average income$ (P = 0.01) – C-reactive protein# (P = 0.0003) Severity of illness at time of PJI (P = 0.04) – White blood cell count# (P = 0.0002) Receipt of dialysis# (P = 0.0007) – Receipt of dialysis (P = 0.006) – – #After PJI revision surgery and prior to initiation of CAS. $Year prior to PJI. Disclosures All authors: No reported disclosures.