2123. High Utilization of Post-Discharge Antibiotics After Mastectomy in a Nationwide Cohort of Commercially Insured Women

Abstract

Background. Prophylactic antibiotics are commonly prescribed at discharge for mastectomy, despite many guidelines recommending discontinuation 24 hours afer surgery. The objective of this study was to determine the prevalence and patterns of post-discharge prophylactic antibiotic use afer mastectomy in a geographically representative, commercially insured population. Methods. We identifed a cohort of women aged 18-64 years undergoing mastectomy between January 2010 and June 2015 using the Truven Health MarketScan Databases. Patients with evidence of an infection during the surgical admission or 30 days prior were excluded. Post-discharge antibiotic use was identifed from outpatient drug claims within 5 days post-discharge. Univariate logistic regression was used to compare antibiotic use by reconstruction type and geographic factors. Results. The analysis included 43,391 mastectomy procedures. The median age was 52 years; 37,687 (86.8%) patients resided in an urban/suburban area; 27,264 (62.8%) of mastectomy procedures involved immediate reconstruction (IR) and 39,825 (91.8%) patients had a diagnosis of breast cancer or carcinoma in situ. Post-discharge prophylactic antibiotics were used in 16,493 (38.0%) surgeries. The most commonly prescribed antibiotics were cephalexin (59.0%), cefadroxil (9.6%), clindamycin (8.3%), and trimethoprim/sulfamethoxazole (TMP/SMX) (7.5%). Antibiotic use did not change signifcantly from 2010 to 2015 for mastectomy only (P = 0.064) or mastectomy + IR (P = 0.1912; Cochran-Armitage test). Mastectomy patients with IR were more likely to be prescribed antibiotics (50.7% of IR vs. 19.8% of mastectomy only; P < 0.001). In mastectomy only and mastectomy + IR, antibiotic use varied by U.S. region (Figure 1). Among mastectomy + IR, the type of post-discharge antibiotic prescribed difered by U.S. region (Figure 2). In mastectomy + IR, TMP/SMX use increased from 2010 to 2015 (3.3% of procedures in 2010 vs. 5.7% in 2015; P < 0.001; Cochran-Armitage test). Conclusion. Post-discharge prophylactic antibiotic use is common afer mastectomy and varies by reconstruction status and U.S. region. Regional variation in prescribing practices is potential targets for antimicrobial stewardship interventions.