Microbiological and clinical outcomes of treating non-MAC NTM pulmonary disease: A systematic review and meta-analysis

BACKGROUND: Pulmonary disease caused by non-tuberculous mycobacteria (NTM) is steadily increasing worldwide.

METHODS: A systematic review of Non-Mycobacterium avium complex studies published prior to October 2016 was conducted with respect to microbiological and clinical outcomes of current treatment regimens.

RESULTS: We retrieved 352 citations; these yielded 24 studies eligible for evaluation. Sixteen studies were retrospective chart reviews, 3 were prospective and only 5 randomized. The weighted average proportion of sputum culture conversions (SCC) after subtracting post-treatment relapses for patients with Mycobacterium abscessus was 41.2% (95% CI; 28.6%-54.5%), but 69.8% (95% CI; 41.0%-91.9%) with subspecies M. massiliense in macrolide-containing regimens, 80.2% (95% CI; 58.4%-95.2%) in patients with M. kansasii (MK), 32.0% (95% CI; 16.5%-49.8%) with M. xenopi (MX) and 54.4% (95% CI; 34.7%-73.4%) with M. malmoense. SCC in the total of 55 patients with lung resection and MX or M. abscessus was high at 75.9%. The risk of bias was low in 4 of 5 randomized studies. However, heterogeneous use of outcome parameters (8 definitions of "relapse," 8 of "treatment success" and 4 of "cure") hampered comparison of non-randomized studies as well as possible bias by a posteriori exclusion (13.3%) and uncompleted treatment of participants (25.3%).

CONCLUSION: As sustained microbiological response without surgery is unsatisfactory in treating M. abscessus, MX and M. malmoense, functional and quality of life aspects should be given more emphasis in the individual evaluation of treatment outcome. Further properly planned studies with sufficient power are needed as well as new drugs and/or better-tolerated application of current antibiotics.