MAC lung disease progression overview
Early identification of MAC lung disease and its progression may impact clinical assessment
Identifying MAC lung disease and key patterns of progression
Diagnosing MAC lung disease requires clinical symptoms, radiologic findings, and positive microbiologic cultures1
The 2020 NTM Guidelines provide diagnostic criteria for identifying MAC lung disease: chronic pulmonary or systemic symptoms, radiological evidence of bronchiectasis and/or fibrocavitary features, and positive MAC sputum cultures.1
Symptoms alone may not provide the full clinical picture. Progression of MAC lung disease can present in various ways and may lead to irreversible lung damage, making it important to recognize and address early.2-5
Indicators that progression has started often include:
Risk factors can help identify the likelihood of MAC lung disease progression10
A retrospective study identified risk factors for MAC lung disease progression in 488 newly diagnosed patients. Within 3 years of diagnosis, untreated patients with comorbidities (including fibrocavitary disease, positive sputum AFB smear, or systemic symptoms) were at a significantly higher risk of clinical deterioration leading to treatment initiation than those without.8
Overlapping symptoms of comorbid conditions, such as bronchiectasis or COPD, may lead to a delayed diagnosis of MAC lung disease, which can contribute to disease progression12
Worsening symptoms that seem to be due to comorbid COPD or bronchiectasis may actually be important signals of MAC lung disease progression.7,13
Once you see MAC lung disease progression, consider reviewing the patient’s treatment plan
Learn about the clinical consequences of MAC lung disease progression
AFB=acid-fast bacilli; CI=confidence interval; FVC=forced vital capacity; HR=hazard ratio; NTM=nontuberculous mycobacteria.
References: 1. Daley CL, Iaccarino JM, Lange C, et al. Treatment of nontuberculous mycobacterial pulmonary disease: an official ATS/ERS/ESCMID/IDSA clinical practice guideline. Clin Infect Dis. 2020;71(4):e1-e36. doi:10.1093/cid/ciaa241 2. Hagiwara E, Katano T, Isomoto K, et al. Clinical characteristics and early outcomes of patients newly diagnosed with pulmonary Mycobacterium avium complex disease. Respir Investig. 2019;57(1):54-59. doi:10.1016/j.resinv.2018.08.006 3. van Ingen J, Obradovic M, Hassan M, et al. Nontuberculous mycobacterial lung disease caused by Mycobacterium avium complex—disease burden, unmet needs, and advances in treatment developments. Expert Rev Respir Med. 2021;15(11):1387-1401. doi:10.1080/17476348.2021.1987891 4. Lee G, Lee KS, Moon JW, et al. Nodular bronchiectatic Mycobacterium avium complex pulmonary disease: natural course on serial computed tomographic scans. Ann Am Thorac Soc. 2013;10(4):299-306. doi:10.1513/AnnalsATS.201303-062OC 5. Winthrop K, Waweru C, Hassan M, et al. Reductions in hospitalisations and emergency department visits with early antibiotic initiation in nontuberculous mycobacterial lung disease. ERJ Open Res. 2024;10(4):1-11. doi:10.1183/23120541.00963-2023 6. Lin C-Y, Huang H-Y, Hsieh M-H, et al. Impacts of nontuberculous mycobacteria isolates in non-cystic fibrosis bronchiectasis: a 16-year cohort study in Taiwan. Front Microbiol. 2022;13:868435. doi:10.3389/fmicb.2022.868435 7. Griffith DE, Aksamit T, Brown-Elliott BA, et al; ATS Mycobacterial Diseases Subcommittee. An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Am J Respir Crit Care Med. 2007;175(4):367-416. doi:10.1164/rccm.200604-571ST 8. Hwang JA, Kim S, Jo KW, Shim TS. Natural history of Mycobacterium avium complex lung disease in untreated patients with stable course. Eur Respir J. 2017;49(3):1600537. doi:10.1183/13993003.00537-2016 9. Pathak K, Hart S, Lande L. Nontuberculous mycobacteria lung disease (NTM-LD): current recommendations on diagnosis, treatment, and patient management. Int J Gen Med. 2022;15:7619-7629. doi:10.2147/IJGM.S272690 10. Pan SW, Shu CC, Feng JY, et al. Microbiological persistence in patients with Mycobacterium avium complex lung disease: the predictors and the impact on radiographic progression. Clin Infect Dis. 2017;65(6):927-934. doi:10.1093/cid/cix479 11. National Jewish Health. Advanced Diagnostic Laboratories. Smear and culture (only) of acid fast bacilli. Accessed May 11, 2026. https://www.nationaljewish.org/for-professionals/diagnostic-testing/advanced-diagnostic-laboratories/smear-culture-acid-fast-bacilli 12. Wang P, Morimoto K, Hasegawa N, Hassan M, Chatterjee A. Nontuberculous mycobacterial pulmonary disease added burden to COPD and bronchiectasis in Japan. ERJ Open Res. 2024;10(4):00911-2023. doi:10.1183/23120541.00911-2023 13. Wang P, Marras TK, Allison PD, Hassan M, Chatterjee A. Identifying potentially undiagnosed nontuberculous mycobacterial lung disease among patients with chronic obstructive pulmonary disease: development of a predictive algorithm using claims data. J Manag Care Spec Pharm. 2023:29(8):927-937.