Postdischarge prophylactic antibiotics following mastectomy with and without breast reconstruction

Abstract

Background: Prophylactic antibiotics are commonly prescribed at discharge for mastectomy, despite guidelines recommending against this practice. We investigated factors associated with postdischarge prophylactic antibiotic use after mastectomy with and without immediate reconstruction and the impact on surgical-site infection (SSI).

Study design: We studied a cohort of women aged 18-64 years undergoing mastectomy between January 1, 2010, and June 30, 2015, using the MarketScan commercial database. Patients with nonsurgical perioperative infections were excluded. Postdischarge oral antibiotics were identified from outpatient drug claims. SSI was defined using International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) diagnosis codes. Generalized linear models were used to determine factors associated with postdischarge prophylactic antibiotic use and SSI.

Results: The cohort included 38,793 procedures; 24,818 (64%) with immediate reconstruction. Prophylactic antibiotics were prescribed after discharge after 2,688 mastectomy-only procedures (19.2%) and 17,807 mastectomies with immediate reconstruction (71.8%). The 90-day incidence of SSI was 3.5% after mastectomy only and 8.8% after mastectomy with immediate reconstruction. Antibiotics with anti-methicillin-sensitive Staphylococcus aureus (MSSA) activity were associated with decreased SSI risk after mastectomy only (adjusted relative risk [aRR], 0.74; 95% confidence interval [CI], 0.55-0.99) and mastectomy with immediate reconstruction (aRR, 0.80; 95% CI, 0.73-0.88), respectively. The numbers needed to treat to prevent 1 additional SSI were 107 and 48, respectively.

Conclusions: Postdischarge prophylactic antibiotics were common after mastectomy. Anti-MSSA antibiotics were associated with decreased risk of SSI for patients who had mastectomy only and those who had mastectomy with immediate reconstruction. The high numbers needed to treat suggest that potential benefits of postdischarge antibiotics should be weighed against potential harms associated with antibiotic overuse.

Figure 1.

Flow Diagram With Exclusion Criteria to Establish Population of Mastectomy Procedures among Women Aged 18–64 Years From January 2010 Through June 2015 in the MarketScan Commercial Database * Excluded procedures lacking claims from both a surgeon and facility, if also without supporting evidence for surgery (i.e., operating room services, pathology, breast reconstruction, anesthesiology claims), procedures only coded by a provider in outpatient surgery encounter if no facility claims within +/− 1 day, and procedures without evidence of performance in a hospital (inpatient or outpatient surgery) or ambulatory surgical center. ** Excluded for major infection coded in the 30 days prior through 2 days post-discharge and minor infection coded in the 14 days prior through 2 days post-discharge.