Nontuberculous mycobacterial lung disease (NTM-LD) is increasingly recognized as an
important predisposing condition for the development of chronic pulmonary aspergillosis
(CPA), but there are limited data on the risk factors for CPA development in NTM-LD
patients. We reviewed the medical records of 566 patients who, at the time of diagnosis of
NTM-LD, did not have CPA and who received 12 months of treatment for NTM-LD
between January 2010 and June 2015. Of these patients, 41 (7.2%) developed CPA (NTMCPA
group), whereas the remaining 525 patients did not develop CPA (NTM group). The
median time to the development of CPA was 18.0 months from treatment initiation for NTMLD.
The NTM-CPA group was older and had significantly higher proportions of males, current
smokers, and patients with a low body mass index (<18.5 kg/m2), when compared to
the NTM group. Moreover, the NTM-CPA group was more likely to have a history of tuberculosis
and chronic obstructive lung disease and to have used inhaled or systemic steroids. In
the NTM-CPA group, more than 40% of patients had Mycobacterium abscessus complex
(MABC) as the cause of NTM-LD, and the fibrocavitary form of NTM-LD was the most common;
both associations were higher than in the NTM group. Overall, 17 (3%) patients died,
and the NTM-CPA group had a higher mortality rate than did the NTM group (19.5% vs.
1.7%, respectively; P<0.001). In a multivariable analysis, old age, male gender, low body
mass index, chronic obstructive lung disease, systemic steroids, MABC as the etiologic
organism, and the fibrocavitary form of NTM-LD remained significant predictors of development
of CPA. In conclusion, CPA occurred in 7.2% of patients after initiation of treatment for
NTM-LD, and some risk factors were associated with CPA development. Given the worse
prognosis, early diagnosis and treatment of CPA are important in patients with NTM-LD.