NTM Cases Up, Especially Among Women and Older Adults

There has been a noted increase in the number of new nontuberculous mycobacterial (NTM) lung disease infections, especially among women and adults aged 65 or older, according to a new report published in the Annals of the American Thoracic Society.

Investigators from Oregon Health & Science University retrospectively studied national managed care claims in order to estimate NTM in order to provide better understanding of the public health and economic impacts of the disease and its treatment. Risk factors for the disease—which only infects a small fraction of the general population—include comorbid chronic obstructive pulmonary disease, cystic fibrosis, or an otherwise immunocompromised system. There are more than 160 different species of NTM bacteria, which are found naturally in the environment.

There were about 27 million members annually in the database the investigators used, which represented a geographically diverse population between 2007 and 2016.

Study author Kevin L. Winthrop, MD, MPH, professor of infectious diseases and public health, told Contagion® that there have been a handful of studies documenting this trend about 5 and 8 years ago. But this current study, he said, is the most recent snapshot which shows a clear trend of increased incidence.

In this study, the investigators learned the annual incidence of NTM increased from 3.13 to 4.37 between 2008 and 2015 per 100,000 person-years. They also found that the annual prevalence increased from 6.78 to 11.70 per 100,000 persons.

Geographically, the incidence of NTM increased by at least 10% in 29 states. The study authors noted that Hawaii and Arizona were consistently in the high range in 2008 and 2015. Additionally, the investigators wrote that the prevalence of NTM increased by at least 10% in 39 states.

“I can tell you anecdotally, from practicing in this area, we get a lot more consults than we used to based on a couple factors,” Winthrop continued. “No question the radiologists have been very aware of this disease the last 10 years. They are paying attention to it on scans as a potential differential diagnosis. That’s leading to workups and consults, and I think increased diagnosis. I think people just get more CT scans than they used to. The factors are definitely driving some of the increased instances — kind of a detection bias.”

Among adults aged 65 years and older, the annual incidence increased from 12.70 to 18.37 per 100,000 person-years. The annual prevalence increased for older adults increased from 30.27 to 47.48 per 100,000 person-years.

For women specifically, the annual incidence increased from 4.16 per 100,000 person-years at the beginning of the study period to 6.69 per 100,000 person-years by the end of the study period. The study authors explained that this might be attributed to the fact that women live longer and could be more likely to seek medical care.

“In the last 5 to 10 years we’ve seen increased interest from industries for drug development, government for funding science around why people get this disease,” Winthrop concluded. “It sets the stage for further development along those lines.”