Microbiological and Clinical Outcomes of Treating Non-Mycobacterium Avium Complex Nontuberculous Mycobacterial Pulmonary Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: Pulmonary disease caused by nontuberculous 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, which yielded 24 studies eligible for evaluation. Sixteen studies were retrospective chart reviews, three studies were prospective, and only five studies were randomized. The weighted average proportion of sputum culture conversion (SCC) after subtracting posttreatment relapses for patients with M abscessus was 41.2% (95% CI, 28.6%-54.5%) but was 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, 32.0% (95% CI, 16.5%-49.8%) for M xenopi (MX) and 54.4% (95% CI, 34.7%-73.4%) for M malmoense. SCCs in the total of 55 patients who underwent lung resection and had MX or M abscessus was high at 75.9%. The risk of bias was low in four of five randomized studies. However, heterogeneous use of outcome parameters (eight definitions of "relapse," eight of "treatment success," and four of "cure") hampered comparison of nonrandomized studies as well as producing possible bias by a posteriori exclusion (13.3%) and uncompleted treatment of participants (25.3%).

CONCLUSIONS: As a 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 are new drugs or better-tolerated application of current antibiotics, or both.