Treatment Regimens Prescribed for Mycobacterium avium complex Infections Diagnosed in Hospitalized Patients throughout the United States, 2008–2013

BACKGROUND: Nontuberculous mycobacteria (NTM) are associated with human lung disease, with 80% of cases caused by Mycobacterium avium complex (MAC). American Thoracic Society (ATS)-led treatment guidelines exist for MAC (macrolide/ethambutol/rifamycin), although studies suggest poor concordance with clinician practice. Using a national database of hospitalized patients with MAC isolated, we sought to characterize US treatment practices and trends. METHODS: Linked demographic and microbiologic data from Premier(TM) Healthcare Database were extracted for all inpatient encounters from 2009 to 2013. Patients with ≥1 positive MAC culture were identified as cases; concomitant pathogens were also identified. Antibiotics ordered within 3-months post-positive culture were evaluated. Regression models were used to estimate the relative risk (RR) for factors associated with receiving an ATS regimen or macrolide monotherapy. RESULTS: Of 3629 MAC cases, 2285 (63%) received an evaluated antibiotic regimen. Most (59%) were treated with a quinolone-based regimen, and 481 (21%) received an ATS regimen. Concordance with ATS guidelines improved over time from 12% in 2009 to 20% in 2013, peaking in 2012(23%). Concordance was highest at facilities in the South (24%) and lowest in the Midwest (13%). Regimens associated with macrolide resistance were given to 160 (7%) cases, including macrolide monotherapy (4%). Guideline concordance was 60% more likely in the South (RR: 1.6, P < 0.01) and 5-fold greater among those who received initial tuberculosis-specific therapy (isoniazid/pyrazinamide, RR: 4.7, P < 0.01). Cases in the Northeast (RR: 2.3, P = 0.02) and without co-infection (only MAC isolated) (RR: 1.7, P = 0.05) were more likely to receive macrolide monotherapy. CONCLUSION: Prescribing concordance with ATS guidelines increased over time. However, regimens associated with macrolide-resistance are still ordered nationally. Clinicians managing hospitalized patients with suspected MAC infections should avoid use of regimens associated with macrolide resistance, which can result in worse clinical outcomes. This work was supported in part by the Division of Intramural Research, NIAID, NIH DISCLOSURES: All authors: No reported disclosures.