Recent studies report increasing incidence and prevalence of nontuberculous mycobacterial lung disease in the United States, while these rates have decreased for other mycobacterial diseases, like tuberculosis. Few national estimates of NTM lung disease burden in the US exist, with the most recent prevalence estimates covering through 2007 and only regional studies—not nationwide—addressing incidence. For a study published in Annals of the American Thoracic Society, Kevin L. Winthrop MD, MPH, and colleagues sought to estimate the yearly incidence and prevalence of administrative claims–based NTM lung disease between 2008 and 2015 in a U.S. managed care claims database. “We needed to determine if initial trends of increasing incidence were continuing and if this problem was most prevalent in specific subgroups of people,” adds Dr. Winthrop.

Using a population-based US claims database representing a geographically diverse population of approximately 27 million members annually, the researchers scanned medical claims from January 2007 to June 2016 for diagnosis codes for NTM lung disease that were dated at least 30 days apart. Annual prevalence and incidence were estimated for each calendar year from 2008 to 2015.

During the study period, the annual incidence of NTM lung disease increased from 3.13 to 4.73 per 100,000 person-years, while the annual prevalence increased from 6.78 to 11.70 per 100,000 persons. Average annual incidence and prevalence changes were +5.2% and +7.5%, respectively. Most cases were women, among whom annual incidence increased from 4.16 to 6.69 per 100,000 person-years and annual prevalence increased from 9.63 to 16.78 100,000 persons. Most cases were older than 50, with annual incidence among those older than 65 increasing from 12.70 to 18.37 per 100,000 person-years and annual prevalence increasing from 30.27 to 47.48 per 100,000 persons.

“The findings of increased incidence over time, a higher incidence in women overall (but currently increasing in both men and women), and higher incidences with advancing age are all important and should increase physician awareness of the possibility that their patient with chronic cough, fatigue, or both—particularly if older than 60—might have this infection,” says Dr. Wintrhop.