Comparison of frailty in patients with nontuberculous mycobacterial lung disease and bronchiectasis: a prospective cohort study

Background The incidence of nontuberculous mycobacterial lung disease (NTM-LD) peaks in middle- and old age groups, coinciding with senescence; thus, chronic infectious diseases can accelerate frailty and worsen mental health in the elderly. In this study, we aimed to compare the prevalence of physical and psychiatric frailty between patients with NTM-LD and bronchiectasis (BE). Methods The Kihon Checklist Questionnaire (KCQ) was used to assess physical and psychiatric frailties and identify those at risk of requiring care among patients with newly diagnosed NTM-LD and BE. Additionally, the Hospital Anxiety and Depression Scale (HADS) scores and chronic inflammatory biomarkers of the alveolar region (surfactant protein [SP]-A, SP-D, and human cationic antibacterial protein [hCAP]/LL-37) were assessed and compared between NTM-LD and BE patients. Results There were no significant differences in the background characteristics between the 33 NTM and 36 BE patients recruited. The KCQ revealed that the proportion of frail NTM patients at diagnosis was higher than that of frail BE patients (48.5% vs. 22.2%, p = 0.026). HADS scores were significantly higher in the NTM group than in the BE group ( p < 0.01). Bronchoalveolar lavage fluid (BALF) hCAP/LL-37 and SP-D levels were significantly higher ( p = 0.001), but serum hCAP/LL-37 levels were significantly lower in the NTM group than in the BE group ( p = 0.023). However, there were no significant differences in the BALF and serum SP-D levels between the two groups. Conclusions The number of frail NTM patients at diagnosis was significantly higher than that of frail BE patients. Biomarker analysis suggested that the former had more localized lung inflammation than the latter. Trial registration This trial was prospectively registered in the Clinical Trials Registry (UMIN 000027652).