Efficacy outcomes in non-tuberculous mycobacterial pulmonary disease studies: a scoping review

Non-tuberculous mycobacterial pulmonary disease (NTM-PD) is increasing in prevalence. However, anti-NTM-PD treatments have low rates of success and are based on low-quality evidence. It’s vital to select appropriate outcomes that reflects the characteristics of NTM-PD to measure the efficacy of interventions. We conducted a scoping review on efficacy outcome selection in NTM-PD studies. We searched full-text databases and trial registries for published articles and study protocols that prospectively investigated the efficacy of NTM-PD treatments. We categorized the outcome measurements into microbiological, radiological, functional and patient-reported, described the distributions and frequency of different outcomes. 77 studies were included in the analysis. The median sample size was 54 (IQR 24.25–137.25). The number of trials increased over time ( P < 0.05). Microbiological endpoints were reported in 70 studies (90.9%), most commonly three consecutive negative sputum cultures. 27 studies (35.1%) predefined radiological endpoints. Functional outcomes were included in 27 studies (35.1%), mainly assessed via the 6-min walk test. 44 studies incorporated patient-reported outcomes (PROs), with the Quality of Life-Bronchiectasis being the most used instrument; only 7 studies included non-tuberculous mycobacteria disease module. In NTM-PD trials, microbiological outcomes are most used, followed by PROs, radiological and functional measures. Future studies need more quantitative microbiological and imaging assessments, along with NTM-PD-specific PROs. Implementing composite endpoints should be considered and formally evaluated.