Ethambutol treatment duration, HIV positivity tied to 1-year improvements in NTM-PD
HIV positivity, the male sex and the duration of ethambutol treatment are all associated with 1-year improvements in patients with probable or definite nontuberculosis mycobacterial pulmonary disease (NTM-PD), according to a retrospective, multicentre study.
“Early predictive factors for a favourable development of … NTM-PD are important to improve management due to the high mortality of this infection at 5 years,” said researchers.
“The purpose of this study was to search for early factors that could predict at the first year the favourable or unfavourable evolution of NTM-PD,” they added.
In the study sample of 119 patients (mean age 50.4±19.4 years; 67.2 percent male) with probable or definite NTM-PD, 46 showed improvements after a year (38.6 percent; mean age 46.1±9.0 y ears; 78.2 percent male) while 73 did not (61.3 percent; mean age 55.0±20.1 years; 60.2 percent male). [PLoS Negl Trop Dis 2017;11:e0005841]
Those who improved were significantly younger (p=0.05) and were more likely to be HIV positive (36.9 vs 16.4 percent; p=0.02).
In a multivariate analysis of all patient data, the male sex was found to be significantly associated with improvements in NTM-PD status at 1 year (odds ratio [OR], 2.34; 95 percent CI, 1.26 to 8.16; p=0.02).
Other factors that were significantly correlated with improvements at 1 year were a positive HIV status (OR, 3.23; 1.27 to 8.45; p=0.01) and a longer ethambutol treatment duration (OR, 2.24; 2.11 to 3.41; p=0.001).
Notably, while the male sex was significantly associated with improvements at 1 year, no substantial gender differences in bacteriological culture findings were observed, and males showed a higher mortality at 1 year.
Indeed, previous studies have shown that “[m]en with NTM-PD have been reported as having a worse prognosis in terms of mortality than women,” explained researchers. [Am J Respir Crit Care Med 2010;181:514-521]
Previous studies have reported similar improvements in NTM-PD symptoms in persons infected with HIV. According to researchers, anti-HIV therapies likely contribute largely to this association. [Swiss Med Wkly 2001;131:471-477]
“Restoration of immunity, monitoring of these patients in specialized structures and treatment of NTM-PD have played an important role in improving prognosis,” they said.
In the subset of patients who were negative for HIV, the male sex (OR, 3.54; 1.12 to 14.0; p=0.04) and the duration of ethambutol treatment (OR, 1.90; 1.50 to 3.50; p=0.001) were significantly associated with improvements at 1 year.
Of all the participants, 57.1 percent (n=68) met the ATS/IDSA (American Thoracic Society and the Infectious Disease Society of America) criteria for NTM-PD and were thus identified as those with definite NTM-PD. In this group, the duration of ethambutol treatment was similarly associated with improvements at 1 year (OR, 2.45; 1.82 to 7.45; p=0.01).
“Identifying predictors of improvement at one year of NTM-PD is expected to optimize the management of the disease in its early stages,” researchers concluded.