Mortality in patients with Mycobacterium avium complex lung disease – a review of published literature
23 February 2017 (online)
Nontuberculous mycobacteria (NTM) are ubiquitous environmental bacteria and the prevalence in human clinical samples is increasing worldwide. Mycobacterium avium Complex (MAC) has been reported to be the most common causative agent in NTM lung disease worldwide. Treatment outcomes in NTM lung disease are sparsely reported and as of today only one systematic literature review on quality of life, co-morbidities and mortality, and one meta-analysis on treatment success rate have been published. However, no review of long-term mortality specifically in patients with MAC lung disease has been published yet.
The objective of the analysis was to collect available data from the published literature on 5-year all-cause mortality in patients with MAC lung disease and to explore study characteristics that may have contributed to variability in all-cause mortality reports.
We have identified 13 published studies reporting 5-year mortality in patients with MAC lung disease. Ten studies were retrospective and three were prospective, with sample sizes from 9 to 782 patients with MAC lung disease. 5-year mortality rates ranged between 10% and 66%, and 10 of the 13 studies reported a rate exceeding 25%. The Q-statistics (Q = 172, degrees of freedom (df)= 12) suggest substantial deviations of study-specific mortality from an aggregate mortality estimate. The I2-statistic (I2= 93%) indicates that 93% of the observed variability in mortality rates was likely due to true heterogeneity in mortality rates among the studies. Lower mortality rates were reported by studies in patients with predominantly nodular disease, whereas higher rates by studies in patients with predominantly cavitary disease or in case of macrolides resistance.
Risk of all-cause mortality in patients with MAC lung disease varies across studies. Most of the studies document a 5-year mortality rate greater than 25%, indicating a substantial health threat to people with the disease.