The epidemiology of nontuberculous mycobacterial pulmonary disease in the Netherlands

BACKGROUND: Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens of humans. Because NTM pulmonary disease (PD) is not a notifiable disease in Europe, the epidemiology of NTM-PD is not well known. However, the prevalence of NTM-PD is thought to be increasing, particularly in countries where tuberculosis rates have decreased. Here we aim to determine the prevalence of NTM-PD in the Netherlands. METHODS: Annual prevalence estimates of NTM-PD in the Netherlands (2012–2019) were derived from four separate databases, including two drug dispensing databases, an ICD-10 code database and a hospitalisation database. Databases covered a fraction of the Dutch population and were extrapolated. In addition, annual NTM-PD prevalence was also estimated by means of a pulmonologist survey. RESULTS: The estimated annual prevalence of NTM-PD using databases is between 2.3 and 5.9 patients per 100 000 inhabitants. Prevalence estimates derived from the drug dispensing databases, the hospitalisation database and the claims database were 2.3, 5.9, 3.5 and 4.5 per 100 000 inhabitants, respectively. The annual prevalence estimated in the pulmonologist survey was between 6.2 and 9.9 per 100 000 inhabitants. The annual prevalence remained stable over the included period. CONCLUSION: The estimated annual prevalence of NTM-PD using databases was between 2.3 and 5.9 patients per 100 000 inhabitants. Due to the possible presence of tuberculosis patients and low coverage in one dispensing database, we believe an annual prevalence of between 2.3 and 4.5 patients per 100 000 inhabitants is more probable, which still renders NTM-PD a serious health threat. This estimate is lower than the estimate from the pulmonologist survey, indicating physicians likely overestimate prevalence.