Nontuberculous mycobacteria accounts for an increasing percentage of pulmonary disease, and nonsurgical treatment alone has not shown effectiveness, according to data from a meta-analysis of 24 studies and 1,224 patients. The study results were published online in Chest.

In particular, non-MAC species Mycobacterium xenopi (MX), Mycobacterium abscessus, Mycobacterium malmoense, and Mycobacterium kansasii (MK) were addressed in the studies, which included 16 retrospective chart reviews, 5 randomized trials, and 3 prospective, nonrandomized studies (Chest 2017. doi: 10.1016/j.chest.2017.04.166).

Treatment success was measured by rates of sputum culture conversion (SCC).

Overall, the average proportion of SCC for patients with M. abscessus was 41% after subtraction for posttreatment relapses, but reached 70% for subspecies M. massiliense in macrolide-containing treatments. The average proportion of SCC was 80% for patients with M. kansasii, 32% for those with MX, and 54% for those with M. malmoense.

Treatment success ranged from 9% to 73% for M. xenopi patients, but all-cause mortality was 69%. Of note, a 100% success rate was noted in M. kansasii patients using a three-drug TB regimen of isoniazid, rifampicin, and ethambutol, or with a combination of ethambutol, rifampicin, and clarithromycin, the researchers noted.

The percentage of SCC in 55 patients with lung resection and either MX or M. abscessus was considered high at 76%.

The study findings were limited by the diverse definitions of treatment success and by the variety of treatments and “an optimal multidrug treatment cannot be derived from the few studies and has yet to be determined,” the researchers said. In the absence of optimal drug therapy, functional and quality of life elements deserve greater consideration when evaluating outcomes in patients with non-MAC NTM pulmonary disease, they added.

Dr. Diel reported receiving lecturing and/or consulting fees from Insmed and Riemser.