# Trends in Non-Tuberculous Mycobacterial Lung Disease and Treatment Outcomes in a Low-Tuberculosis Prevalence Setting: A Retrospective Analysis

## TL;DR

This study examines trends and treatment outcomes of non-tuberculous mycobacterial lung disease in Norway, finding a high relapse rate despite a majority showing favorable responses to treatment.

## Contribution

The study provides insights into NTM lung disease trends and treatment outcomes in a low-tuberculosis prevalence setting.

## Key findings

- 74% of treated patients showed a favorable response, but 32% experienced relapse.
- 47% of patients received antibiotic treatment, with factors like high symptom scores and MAC infection increasing treatment odds.
- 55% of untreated patients had spontaneous culture conversion, with 18% experiencing relapse.

## Abstract

Background: Information on the management of non-tuberculous mycobacterial (NTM) lung infection and disease is scarce. The aim of this study was to investigate the trends in NTM lung infections, and the factors associated with the initiation of treatment and treatment outcomes. Methods: A retrospective analysis was carried out on patient medical records from Haukeland University Hospital, Bergen, Norway, from 2000 to 2021. Results: Among 154 patients with NTM lung infection, the majority (70%) were older than 65 years, and 49% had an underlying pulmonary comorbidity. The most frequently observed mycobacterial species was M. avium complex (MAC), followed by M. malmoense and M. abscessus. In total, 72 (47%) patients received antibiotic treatment. Patients with high symptom scores, aged below 65, and with MAC infection had more than three times the odds of receiving antibiotic treatment. A favourable response and culture conversion was observed in 53 of 72 (74%) patients. However, 17 (32%) of them had a relapse. Out of 82 patients who did not receive treatment, 45 (55%) had spontaneous culture conversion, and 8 (18%) of them had a relapse. No factor was identified to be significantly associated with a favourable treatment response. Conclusion: A favourable response to treatment was seen in 74% of patients with a high relapse rate.