Pulmonary Nontuberculous Mycobacterial Disease Prevalence and Clinical Features

TLDR

Respiratory specimens containing nontuberculous mycobacteria are increasingly common, yet the prevalence of pulmonary disease caused by these organisms remains unknown. This study aimed to determine the prevalence, clinical characteristics, and risk factors for pulmonary NTM disease and to assess how well the ATS/IDSA microbiologic criteria predict true disease. Researchers identified all Oregon residents with at least one respiratory NTM isolate during 2005–2006, then collected clinical and radiologic data from a population‑based subset and applied the ATS/IDSA criteria to define disease. Among 807 isolates, 134 of 283 evaluable patients (47 %) met ATS/IDSA disease criteria, yielding a 2‑year prevalence of 8.6 per 100,000 overall and 20.4 per 100,000 in those ≥50 years, with most cases caused by Mycobacterium avium complex, frequent cavitation, bronchiectasis, COPD, and immunosuppression, and 86 % of microbiologic‑criteria‑positive patients also meeting full criteria.

Abstract

Rationale: Respiratory specimens with nontuberculous mycobacteria (NTM) are increasingly common; however, pulmonary disease prevalence is unknown.Objectives: To determine the disease prevalence, clinical features, and risk factors for NTM disease, and to examine the predictive value of the microbiologic criteria of the American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) pulmonary NTM case definition for true NTM disease.Methods: We identified all Oregon residents during 2005–2006 with at least one respiratory mycobacterial isolate. From a population-based subset of these patients, we collected clinical and radiologic information and used the ATS/IDSA pulmonary NTM disease criteria to define disease.Measurements and Main Results: In the 2-year time period, 807 Oregonians had one or more respiratory NTM isolates. Four hundred and seven (50%) resided within the Portland metropolitan region, among which 283 (70%) had evaluable clinical records. For those with records, 134 (47%) met ATS/IDSA pulmonary NTM disease criteria for a minimum overall 2-year period prevalence of 8.6/100,000 persons, and 20.4/100,000 in those at least 50 years of age within the Portland region. Case subjects were 66 years of age (median; range, 12–92 yr), frequently female (59%), and most with disease caused by Mycobacterium avium complex (88%). Cavitation (24.5%), bronchiectasis (16%), chronic obstructive pulmonary disease (28%), and immunosuppressive therapy (25.5%) were common. Eighty-six percent of patients meeting the ATS/IDSA microbiologic criteria for disease also met the full ATS/IDSA disease criteria.Conclusions: Respiratory NTM isolates frequently represent disease. Pulmonary NTM disease is not uncommon, particularly among elderly females. The ATS/IDSA microbiologic criteria are highly predictive of disease and could be useful for laboratory-based NTM disease surveillance.