ABSTRACT
Background
Patients with non-tuberculous mycobacterial pulmonary disease (NTM-PD) have impaired exercise capacity, but the underlying factors are unknown. We investigated the characteristics of patients with NTM-PD and impaired exercise capacity.
Methods
In total, 149 patients with NTM-PD participated in this study. Patients completed the incremental shuttle walk test (ISWT) to assess exercise capacity. Peripheral muscle strength and pulmonary function were also assessed. Radiological findings were classified into three phenotypes: non-cavitary nodular bronchiectatic (NC-NB) form, cavitary nodular bronchiectatic form, and fibrocavitary (FC) form.
Results
The median ISWT distance (ISWD) and %ISWD were 450 meters and 88%. Participants were classified into three groups according to %ISWD, with %ISWD <60% as the severely decreased group, 60%-80% as the moderately decreased group, and >80% as the normal or mildly decreased group. In a comparison of %ISWD among phenotypes, FC form had significantly lower %ISWD than those with NC-NB form. In the severely decreased group, peripheral muscle strength and pulmonary function were significantly lower than the other two groups. From a radiological standpoint, significantly more patients had FC form in the group with severely decreased %ISWD.
Conclusions
Decreased ISWD is characterized by a deterioration in physical function and the presence of FC lesions in NTM-PD.
Acknowledgments
We thank Yuki Toyoda (Respiratory Care and Rehabilitation Center, Fukujuji Hospital, Japan Anti-Tuberculosis Association, Tokyo, Japan) for collecting data. We thank Analisa Avila, MPH, ELS, of Edanz (https://jp.edanz.com/ac) for editing a draft of this manuscript.
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
Author contributions
Study conception and design: K. Ono, H. Kimura and H. Senjyu.
Data collection: K. Ono, M. Tabusadani, K. Yamane, S. Takao, K. Mori, Y. Matsumura, Y. Kuroyama, K. Kawahara, S. Omatsu, K. Furuuchi, K. Fujiwara, K. Morimoto.
Data analysis and interpretation: K. Ono, H. Kimura and H. Senjyu.
Manuscript preparation: K. Ono, H. Kimura and H. Senjyu.
Manuscript final review: All authors
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.