LAUSR

Prognosis for patients with MAB lung disease is poor. We sought to examine the potential association between culture conversion and outcomes (progression, mortality) in patients with MAB lung disease. English-language MAB lung disease studies with ≥ 10 patients and reporting mortality and/or microbiological outcomes were identified from Embase, PubMed, relevant congress abstracts, and the Cochrane Library (data cutoff, September 24, 2019) using the National Institute for Health and Clinical Excellence guidance for systematic literature reviews. Two independent reviewers screened 1,551 indexed records; relevant extracted data are expressed as population-weighted means. Mean all-cause mortality across 17 studies (N=1,291) was 12.1% (range, 3%–33%); mortality attributable to MAB lung disease was 7.6% (range, 0%–27%; N=526, 9 studies). Culture conversion across 44 studies (N=2,237) was 46.7% (range, 0%–98.6%), with higher rates reported for M. massiliense subspecies (76.9%; N=507,15 studies) than M. abscessus subspecies (35.8%; N=834,18 studies). No direct comparisons were made between mortality and culture conversion; in the 13 studies (N=1,202) that reported both outcomes there was a moderate correlation between increased rate of culture conversion and decreased MAB-attributable mortality (R2=0.60). The most common definition of progression (21 studies) was radiographic worsening supported by persistent symptoms and/or positive cultures. Across 8 studies (N=415) 57.8% patients had improvement while 35.2% progressed with treatment. A broad variance in treatment regimen and duration (range, 32 days to > 3 years) was observed. Limitations include a small number of studies, and inconsistency in methods and outcomes definitions. In this systematic literature review, available data suggest that culture conversion was achieved in less than half of patients and was lower in patients with M. abscessus compared with M. massiliense. One third of patients had disease progression despite treatment. Some data suggest lower MAB-attributed mortality outcomes in studies with higher culture conversion rates, more evidence is needed to demonstrate a survival benefit associated with culture conversion. Kevin L Winthrop, MD, MPH, Insmed Incorporated (Consultant, Grant/Research Support) Kevin C Mange, MD, MSCE, Insmed Incorporated (Employee) Zhanna Jumadilova, MD, Insmed Incorporated (Employee) Kristan B Cline, PhD, Insmed Incorporated (Employee) Patrick A Flume, MD, Insmed Incorporated (Grant/Research Support, Scientific Research Study Investigator, Advisor or Review Panel member)