Background: Previous UK studies investigating the incidence and prevalence of nontuberculous mycobacteria have been limited to reporting isolation from culture, as opposed to the burden of disease. We assessed the burden of nontuberculous mycobacterial disease (NTMD) in primary care in the UK.

Methods: Using primary care electronic healthcare records (Clinical Practice Research Datalink), we identified patients with NTMD using a strict definition including patients with appropriate treatment/monitoring as determined by guidelines. We described treatment regimens and incidence/prevalence in the general population and in patients with underlying chronic respiratory diseases.

Results: We identified 1,262 patients with NTMD. Incidence of NTMD in the general population decreased (2006 to 2016 rates per 100,000 person-years: 3.85 to 1.28). Average annual prevalence rate of NTMD in the general population was 6.38 per 100,000. Around 85% were taking antimycobacterial therapy; 53.2% were taking a guideline-recommended regimen. Incidence of NTMD in patients with underlying respiratory disease trended downwards (2006 to 2016 rates per 100,000 person-years: 12.5 to 7.40). Average annual prevalence rate of NTMD in patients with underlying respiratory disease was 27.7 per 100,000.

Conclusions: This is the first UK study using nationally-representative data to investigate the clinical burden of NTMD within primary care. Incidence and prevalence of NTMD managed within primary care is gradually declining. Incidence decreased, while prevalence remained steady, in patients with underlying respiratory disease. Half of patients did not appear to be treated along recommendations; indicating a need for better patient management.