The Long and Winding Road: Three-year Mortality Following Prescription of Multidrug Antibiotic Treatment for Mycobacterium avium complex Pulmonary Disease in United States Medicare Beneficiaries With Bronchiectasis

Cara D Varley; Jennifer H Ku; Emily Henkle; Luke Strnad; Kevin L Winthrop

doi:10.1093/ofid/ofae639

The Long and Winding Road: Three-year Mortality Following Prescription of Multidrug Antibiotic Treatment for Mycobacterium avium complex Pulmonary Disease in United States Medicare Beneficiaries With Bronchiectasis

Open Forum Infect Dis. 2024 Nov 6;11(11):ofae639. doi: 10.1093/ofid/ofae639. eCollection 2024 Nov.

Authors

Cara D Varley^{1

2}, Jennifer H Ku^{2

3}, Emily Henkle², Luke Strnad^{1

2}, Kevin L Winthrop^{1

2}

Affiliations

¹ Division of Infectious Diseases, Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA.
² Center for Infectious Disease Studies, Oregon Health & Science University-Portland State University School of Public Health, Portland, Oregon, USA.
³ Department of Research & Evaluation, Kaiser Permanente Southern California Medical Group, Pasadena, California, USA.

Abstract

Background/aims: Although increased mortality has been reported among people with Mycobacterium avium complex pulmonary disease (MAC-PD), data are limited on survival associated with various antibiotic regimens used to treat MAC-PD. We conducted a comparative analysis of 3-year mortality in Medicare beneficiaries with bronchiectasis using various MAC-PD regimens.

Methods: We included Medicare beneficiaries aged ≥65 years with bronchiectasis (01/2006-12/2014). We limited our cohort to new MAC-PD therapy users. MAC-PD therapy was defined as ≥60-day prescriptions for a macrolide plus ≥1 other MAC-PD antibiotic. Guideline-based therapy (GBT) included a macrolide, ethambutol, and/or rifamycin. Using Cox proportional hazard models, we calculated adjusted hazard ratios (aHR) for death up to 3 years after therapy start between the following groups: (1) 2007 GBT versus non-GBT; (2) 2020 GBT versus non-GBT; and (3) macrolide-ethambutol-rifamycin (3-drug) versus macrolide-ethambutol (2-drug).

Results: We identified 4820 new MAC-PD therapy users, of whom 866 (17.9%) were deceased within 3 years of therapy initiation. Of 3040 (63.1%) beneficiaries prescribed 2007 GBT, 472 (15.5%) were deceased by 3 years, compared to 394 (22.1%) of 1780 (36.9%) prescribed non-GBT (aHR 0.82; 95% confidence interval [CI], .72-.94). We observed a similar trend for 2020 GBT versus non-GBT (aHR 0.81; 95% CI, .70-.94]). Three-year-mortality was similar between those starting 3-drug versus 2-drug regimens (aHR 0.89; 95% CI, .74-1.08]).

Conclusions: Among Medicare new MAC-PD therapy users, 3-year-mortality was higher in those prescribed non-GBT regimens compared to GBT regimens. Whether this finding suggests improved efficacy of GBT and/or differential characteristic of those using non-GBT regimens deserves further study.

Keywords: Mycobacterium avium complex; Nontuberculous mycobacteria; bronchiectasis; evidence based medicine; infectious disease guidelines; mortality; pulmonary infections.