Global prevalence of non-tuberculous mycobacteria in adults with non-cystic fibrosis bronchiectasis 2006-2021: a systematic review and meta-analysis

Objective To accurately estimate the global prevalence of non-tuberculous mycobacteria (NTM) in adults with non-cystic fibrosis (non-CF) bronchiectasis and to determine the proportion of NTM species and subspecies in clinical patients from 2006 to 2021. Design Systematic review and meta-analysis using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data sources Medline, Embase, Cochrane Library and Web of Science were searched for articles published between 2006 and 2021. Eligibility criteria for selecting studies We included all the prospective or retrospective studies without language restrictions and all patients were adults (>= 18 years of age) with non-CF bronchiectasis. The studies estimated the effect size of the prevalence of NTM with a sample size >= 40, and patients were registered in and after 2006. Data extraction and synthesis Two reviewers screened the titles, abstracts and full texts independently. Relevant information was extracted and curated into tables. Risk of bias was evaluated following the Cochrane Collaboration's tool. Meta-analysis was performed with software R Statistics V.3.6.3 using random effect model with 95% CI. I-2 index and Q statistics were calculated to assess the heterogeneity, and mixed-effects meta-regression analyses were performed to identify the sources of heterogeneity. The proportions of NTM subspecies were examined using Shapiro-Wilk normality test in R. Results Of all the 2014 studies yielded, 24 met the inclusion criteria. Of these, 14 were identified to be randomised controlled studies and included for an accurate estimation. The global prevalence of NTM in adults with non-CF bronchiectasis from 2006 to 2021 was estimated to be approximately 10%, with great variations primarily due to geographical location. Mycobacterium avium complex was the most common subspecies, followed by Mycobacterium simiae and Mycobacterium gordonae. Conclusions The prevalence of NTM in adults with non-CF bronchiectasis has been on the rise and the most common subspecies changed greatly in recent years. More cohort studies should be done in many countries and regions for future estimates. PROSPERO registration number CRD42020168473.