Factors associated with lung function decline in patients with non-tuberculous mycobacterial pulmonary disease

Phenotypical characteristics of nontuberculous mycobacterial infection in patients with bronchiectasis

BACKGROUND

The global mortality and morbidity rates of bronchiectasis patients due to nontuberculous mycobacteria (NTM) pulmonary infection are on a concerning upward trend. The aims of this study to identify the phenotype of NTM-positive individuals with bronchiectasis.

METHODS

A retrospective single-center observational study was conducted in adult patients with bronchiectasis who underwent bronchoscopy in 2007-2020. Clinical, laboratory, pulmonary function, and radiological data were compared between patients with a positive or negative NTM culture.

RESULTS

Compared to the NTM-negative group (n=677), the NTM-positive group (n=94) was characterized (P ≤0.05 for all) by older age, greater proportion of females, and higher rates of gastroesophageal reflux disease and muco-active medication use; lower body mass index, serum albumin level, and lymphocyte and eosinophil counts; lower values of forced expiratory volume in one second, forced vital capacity, and their ratio, and lower diffusing lung capacity for carbon monoxide; higher rates of bronchiectasis in both lungs and upper lobes and higher number of involved lobes; and more exacerbations in the year prior bronchoscopy. On multivariate analysis, older age (OR 1.05, 95% CI 1.02-1.07, P=0.001), lower body mass index (OR 1.16, 95% CI 1.16-1.07, P <0.001), and increased number of involved lobes (OR 1.26, 95% CI 1.01-1.44, P=0.04) were associated with NTM infection.

CONCLUSIONS

Patients with bronchiectasis and NTM pulmonary infection are more likely to be older and female with more severe clinical, laboratory, pulmonary function, and radiological parameters than those without NTM infection. This phenotype can be used for screening patients with suspected NTM disease.

Proposed Etiotypes for Chronic Obstructive Pulmonary Disease: Controversial Issues

The 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) revised the definition of chronic obstructive pulmonary disease (COPD) to broadly include a variety of etiologies. A new taxonomy, composed of etiotypes, aims to highlight the heterogeneity in causes and pathogenesis of COPD, allowing more personalized management strategies and emphasizing the need for targeted research to understand and manage COPD better. However, controversy arises with including some diseases under the umbrella term of COPD, as their clinical presentations and treatments differ from classical COPD, which is smoking-related. COPD due to infection (COPD-I) and COPD due to environmental exposure (COPD-P) are classifications within the new taxonomy. Some disease entities in these categories show distinct clinical features and may not benefit from conventional COPD treatments, raising questions about their classification as COPD subtypes. There is also controversy regarding whether bronchiectasis with airflow limitations should be classified as an etiotype of COPD. This article discusses controversial issues associated with the proposed etiotypes for COPD in terms of COPD-I, COPD-P, and bronchiectasis. While the updated COPD definition by GOLD 2023 is a major step towards recognizing the disease's complexity, it also raises questions about the classification of related respiratory conditions. This highlights the need for further research to improve our understanding and approach to COPD management.

Clinical phenotypes of nontuberculous mycobacterial disease by cluster analysis based on pulmonary function

BACKGROUND

Nontuberculous mycobacterial pulmonary disease (NTM-PD) often exhibits pulmonary function impairment, such as obstructive or restrictive pattern, with variation among patients according to the damaged lesions in the lung.

METHODS

Patients with NTM-PD were consecutively enrolled between September 2019 and December 2020 at the Respiratory Infection Clinic of our hospital. Patients' data were comprehensively collected through laboratory examinations, PFT, chest computed tomography, and questionnaires for the assessment of subjective symptoms and health-related quality of life (HRQOL). Hierarchical cluster analysis was performed using PFT parameters to compare the clinical findings among clusters.

RESULTS

Data of 104 patients were analyzed and classified into four clusters. The restrictive pattern with decreased forced expiratory volume in 1 s (FEV1) group showed high serum C-reactive protein and low albumin levels, severe radiological findings, and low HRQOL. In the restrictive pattern with preserved FEV1 group, HRQOL was as low as that in the restrictive pattern with decreased FEV1 group, and bacterial exacerbation was observed relatively frequently. HRQOL in the obstructive impairment group was maintained in comparison with that in the normal group.

CONCLUSION

NTM-PD phenotypes were identified using cluster analysis based on PFT. Two different severe phenotypes were also observed. In the early stages of NTM-PD, PFT may be useful in recognizing disease progression.

Identification of Significant Pathogenic Nontuberculous Mycobacteria Species from Presumptive TB Patients Using Partial hsp65 Gene Sequencing

Purpose

To date, the diagnosis of nontuberculous mycobacteria (NTM) disease primarily relies on clinical symptoms and radiological features. Our objective was to apply a sequence-based analysis method by using partial gene sequencing of heat shock protein 65 (hsp65) to identify NTM species.

Patients and Methods

A total of 32 stored isolates obtained from individuals suspected of having pulmonary NTM infection were subjected to solid Ogawa culture. Genomic DNA from each sample was extracted and used in a conventional polymerase chain reaction (PCR) targeting a specific region of hsp65 gene. Identified amplicons from the PCR were then subjected to targeted sequencing. Analysis of the obtained hsp65 sequence was performed using DNA Baser tool. The consensus sequences obtained were compared to references in the GenBank NCBI database to determine NTM species.

Results

We identified several important NTM species which posses opportunistic characteristics. M. abscessus and M. chelonae are the most frequent NTM species identified in this study (40.63% and 18.75%, respectively). These two species have the potential to cause significant infections in human, ranging from opportunistic pulmonary infection to localized skin infection. Additionally, pathogenic NTM members of M. fortuitum group (MFG), M. avium, M. intracellulare, M. kansasii, and M. celatum were also found among all identified species.

Conclusion

Sequence-based analysis is a promising method for identifying species of NTM. The hsp65 gene has a high discriminatory power to identify opportunistic pathogen NTM species in specimens in Indonesia. Consequently, hsp65 partial gene sequencing is considerable as an alternative and reliable approach for NTM speciation.

The cell envelope of Mycobacterium abscessus and its role in pathogenesis

Mycobacterium abscessus is a nontuberculosis mycobacterium (NTM) that has shown an exponential rise in its ability to cause disease. Due to its ubiquitous presence in the environment, M. abscessus is widely implicated in secondary exacerbations of many nosocomial infections and genetic respiratory disorders, such as cystic fibrosis (CF). Contrary to other rapidly growing NTMs, the cell envelope of M. abscessus harbors several prominent features and undergoes modifications that are responsible for its pathogenesis. Compositional changes of the mycobacterial outer membrane (MOM) significantly decrease the presence of glycopeptidolipids (GPLs) and enable the transition from a colonizing, smooth morphotype into a virulent, rough morphotype. The GPLs are transported to the MOM by the Mycobacterial membrane proteins Large (MmpL), which further act as drug efflux pumps and confer antibiotic resistance. Lastly, M. abscessus possesses 2 type VII secretion systems (T7SS): ESX-3 and ESX-4, both of which have recently been implicated in host-pathogen interactions and virulence. This review summarizes the current knowledge of M. abscessus pathogenesis and highlights the clinically relevant association between the structure and functions of its cell envelope.

The Impact of Nontuberculous Mycobacteria Species on Mortality in Patients With Nontuberculous Mycobacterial Lung Disease

Patients with nontuberculous mycobacterial lung disease (NTM-LD) have increased mortality. The impact of NTM species on the risk of mortality remains unclear, especially that of death by non-cancer causes. We conducted a retrospective cohort study from 2006 to 2018 in a tertiary-care hospital in Taiwan. We enrolled patients who fulfilled the microbiological diagnostic criteria of NTM-LD. The mortality causes within 8 years after diagnosis were identified, and the Cox proportional hazard regression was performed for risk factors of mortality. A total of 1,652 subjects with NTM-LD were included. Among them, 723 (43.8%) were infected by Mycobacterium avium complex (MAC), 408 (24.7%) by M. abscessus complex (MABC), 120 (7.3%) by Mycobacterium kansasii (MK), 304 (18.4%) by other rapid-growing mycobacteria (RGM), and 97 (5.9%) by other slow-growing mycobacteria (SGM) groups. The 8-year all-cause mortality was 45.2% for all and the highest in the MK-LD group (59.2%), followed by the MABC-LD and MAC-LD groups. The adjusted hazard ratios were 2.20 (95% confidence interval: 1.40–3.46) in the MK-LD, 1.85 (1.54–2.22) in the MABC-LD, and 1.65 (1.12–2.41) in the MAC-LD groups for all-cause mortality, compared with the SGM group. Kaplan–Meier survival curves showed that all-cause mortality, non-cancer mortality, and mortality due to chronic airway diseases were significantly correlated with NTM species (log-rank p = 0.0031, < 0.001, and 0.001, respectively). High 8-year mortality rates were found in patients with NTM-LDs according to different NTM species. Notably, the difference was significant in non-cancer mortality causes, especially in chronic airway diseases.

The Clinical Significance of Programmed Death-1, Regulatory T Cells and Myeloid Derived Suppressor Cells in Patients with Nontuberculous Mycobacteria-Lung Disease

Background: Increasing expression of programmed death-1 (PD-1) in patients with nontuberculous mycobacteria lung disease (NTM-LD) has been reported, but its role in clinical characteristics and outcomes remains unclear. Methods: We enrolled 96 participants, including 46 with Mycobacterium avium complex (MAC)-LD, 23 with M. abscessus (MAB)-LD, and 27 controls. We measured expressions of PD-1, cytotoxic T-lymphocyte antigen-4 (CTLA-4) and regulatory T (Treg) cells on CD4⁺ lymphocytes and myeloid-derived suppressor cells (MDSCs) and analyzed their association with clinical features and radiographic outcomes. Results: The percentage of PD-1 on CD4⁺(PD-1⁺CD4⁺) lymphocytes and MDSCs were higher in the MAC-LD group than the controls. There were no intergroup differences regarding CTLA-4⁺CD4⁺ lymphocytes. Higher PD-1⁺CD4⁺ lymphocytes were found in M. intracellulare- and M. avium-LD than in other MAC-LD. Positive sputum acid-fast stains and fibrocavitary radiographic lesions were correlated with elevated PD-1⁺CD4⁺ lymphocytes and Treg cells. The percentage of PD-1⁺CD4⁺ lymphocytes at the initial and 2 months of follow-up significantly predicted subsequent radiographic progression. Conclusion: As markers of immune tolerance, PD-1⁺CD4⁺ lymphocytes and MDSCs were higher in MAC-LD patients. The levels of PD-1⁺CD4⁺ and Treg cells were correlated with high mycobacteria bacilli burden in NTM-LD. Monitoring the expressions of PD-1⁺CD4⁺ lymphocytes may predict radiographic progression.

Treatment of Mycobacterium avium Complex Pulmonary Disease

The pathogen Mycobacterium avium complex (MAC) is the most common cause of nontuberculous mycobacterial pulmonary disease worldwide. The decision to initiate long-term antibiotic treatment is difficult for the physician due to inconsistent disease progression and adverse effects associated with the antibiotic treatment. The prognostic factors for the progression of MAC pulmonary disease are low body mass index, poor nutritional status, presence of cavitary lesion(s), extensive disease, and a positive acid-fast bacilli smear. A regimen consisting of macrolides (clarithromycin or azithromycin) with rifampin and ethambutol has been recommended; this regimen significantly improves the treatment of MAC pulmonary disease and should be maintained for at least 12 months after negative sputum culture conversion. However, the rates of default and disease recurrence after treatment completion are still high. Moreover, treatment failure or macrolide resistance can occur, although in some refractory cases, surgical lung resection can improve treatment outcomes. However, surgical resection should be carefully performed in a well-equipped center and be based on a rigorous risk-benefit analysis in a multidisciplinary setting. New therapies, including clofazimine, inhaled amikacin, and bedaquiline, have shown promising results for the treatment of MAC pulmonary disease, especially in patients with treatment failure or macrolide-resistant MAC pulmonary disease. However, further evidence of the efficacy and safety of these new treatment regimens is needed. Also, a new consensus is needed for treatment outcome definitions as widespread use of these definitions could increase the quality of evidence for the treatment of MAC pulmonary disease.

Surgical management of non-cystic fibrosis bronchiectasis

Non-cystic fibrosis bronchiectasis (bronchiectasis) is an abnormal dilatation of the bronchi and bronchioles, resulting from a prolonged recurrent infectious process due to various causes and predisposing factors. This disease has several etiologies and affects a heterogeneous population of patients. The most important viewpoint for the surgical management of bronchiectasis is to select appropriate candidates for surgery and conduct suitable anatomic lung resections at the right time under appropriate conditions. The ideal candidates for lung resection are symptomatic patients with focal disease due to truly localized bronchial pathology regardless of optimal and absolute medical management.

The Clarithromycin Susceptibility Genotype Affects the Treatment Outcome of Patients with Mycobacterium abscessus Lung Disease

Mycobacterium abscessus accounts for a large proportion of lung disease cases caused by rapidly growing mycobacteria. The association between clarithromycin sensitivity and treatment outcome is clear. However, M. abscessus culture and antibiotic susceptibility testing are time-consuming. Clarithromycin susceptibility genotyping offers an alternate, rapid approach to predicting the efficacy of clarithromycin-based antibiotic therapy. M. abscessus lung disease patients were divided into two groups based upon the clarithromycin susceptibility genotype of the organism isolated. A retrospective analysis was conducted to compare the clinical features, microbiological characteristics, and treatment outcomes of the two groups. Several other potential predictors of the response to treatment were also assessed. Sixty-nine patients were enrolled in the clarithromycin-resistant genotype group, which included 5 infected with rrl 2058-2059 mutants and 64 infected with erm(41)T28-type M. abscessus; 31 were in the clarithromycin-sensitive group, i.e., 6 and 25 patients infected with genotypes erm(41)C28 and erm(41) M type, respectively. The results showed that lung disease patients infected with clarithromycin-sensitive and -resistant M. abscessus genotypes differed significantly in clarithromycin-based combination treatment outcomes. Patients infected with the clarithromycin-sensitive genotype exhibited higher initial and final sputum-negative conversion and radiological improvement rates and better therapeutic outcomes. Multivariate analysis demonstrated that genotyping was a reliable and, more importantly, rapid means of predicting the efficacy of clarithromycin-based antibiotic treatment for M. abscessus lung disease.

Performance of a Highly Sensitive Mycobacterium tuberculosis Complex Real-Time PCR Assay for Diagnosis of Pulmonary Tuberculosis in a Low-Prevalence Setting: a Prospective Intervention Study

The potential impact of routine real-time PCR testing of respiratory specimens from patients with presumptive tuberculosis in terms of diagnostic accuracy and time to tuberculosis treatment inception in low-prevalence settings remains largely unexplored. We conducted a prospective intervention cohort study. Respiratory specimens from 1,020 patients were examined by acid-fast bacillus smear microscopy, tested by a real-time Mycobacterium tuberculosis complex PCR assay (Abbott RealTime MTB PCR), and cultured in mycobacterial media. Seventeen patients tested positive by PCR (5 were acid-fast bacillus smear positive and 12 acid-fast bacillus smear negative), and Mycobacterium tuberculosis was recovered from cultures for 12 of them. Patients testing positive by PCR and negative by culture (n = 5) were treated and deemed to have responded to antituberculosis therapy. There were no PCR-negative/culture-positive cases, and none of the patients testing positive for nontuberculous mycobacteria (n = 20) yielded a positive PCR result. The data indicated that routine testing of respiratory specimens from patients with presumptive tuberculosis by the RealTime MTB PCR assay improves the tuberculosis diagnostic yield and may reduce the time to antituberculosis treatment initiation. On the basis of our data, we propose a novel mycobacterial laboratory algorithm for tuberculosis diagnosis.

Change in lung function in never-smokers with nontuberculous mycobacterial lung disease: A retrospective study

Purpose

Never-smokers account for a large proportion of subjects in general population studies on nontuberculous mycobacteria lung disease (NTM-LD). However, the influence of NTM infection on the lung function of never-smokers has not yet been evaluated. The aim of this study was to determine how NTM-LD impairs the lung function in never-smokers, and whether there are an association between successful NTM-LD treatment in radiologic outcomes and improvement in lung function of never-smokers with NTM-LD or not.

Methods

We performed a retrospective study of patients (1) who have never smoked during their lifetime; (2) with at least two respiratory specimens from sputum, one bronchial washing sample, or one lung tissue that were culture positive for the same NTM species; and (3) who underwent at least two pulmonary function tests. We enrolled healthy never-smokers as the control group.

Results

In 22 never-smokers with NTM-LD, the median forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) at baseline was lower than those in 9 healthy never-smokers [1800 vs 2080 ml (p = 0.23) and 2230 vs 2620 ml (p = 0.06)], respectively. The median change in FEV₁ in never-smokers with NTM-LD was lower than that in healthy never-smokers [−70 vs 20 ml per year (p = 0.07), respectively]. On univariate analysis, baseline %-predicted FEV₁ in never-smokers with NTM-LD was associated with changes in FVC (p = 0.026) and FEV₁ (p = 0.013). Anti-NTM treatment was administered for at least 1 year in 19 patients (86.4%). The relationship between worsening chest CT findings and rapid progressive decline in both FVC (p = 0.66) and FEV₁ (p = 0.23) were not significant.

Conclusion

Never-smokers with NTM-LD showed lung function decline. There was no association between successful NTM-LD treatment in radiologic outcomes and improvement in lung function of never-smokers.

Progression and Treatment Outcomes of Lung Disease Caused by Mycobacterium abscessus and Mycobacterium massiliense

BACKGROUND

Mycobacterium abscessus and Mycobacterium massiliense are grouped as the Mycobacterium abscessus complex. The aim of this study was to elucidate the differences between M. abscessus and M. massiliense lung diseases in terms of progression rate, treatment outcome, and the predictors thereof.

METHODS

Between 1 January 2006 and 30 June 2015, 56 patients and 54 patients were diagnosed with M. abscessus and M. massiliense lung diseases, respectively. The time to progression requiring treatment and treatment outcomes were compared between the 2 groups of patients, and predictors of progression and sustained culture conversion with treatment were analyzed. In addition, mediation analysis was performed to evaluate the effect of susceptibility to clarithromycin on treatment outcomes.

RESULTS

During follow-up, 21 of 56 patients with M. abscessus lung diseases and 21 of 54 patients with M. massiliense lung diseases progressed, requiring treatment. No difference was detected in the time to progression between the 2 patient groups. Lower body mass index, bilateral lung involvement, and fibrocavitary-type disease were identified as predictors of disease progression. Among the patients who began treatment, infection with M. massiliense rather than M. abscessus and the use of azithromycin rather than clarithromycin were associated with sustained culture conversion. The difference in treatment outcomes was partly mediated by the organism's susceptibility to clarithromycin.

CONCLUSIONS

Progression rates were similar but treatment outcomes differed significantly between patients with lung disease caused by M. abscessus and M. massiliense. This difference in treatment outcomes was partly explained by the susceptibility of these organisms to clarithromycin.

Mycobacterium abscessus Complex Infections in Humans

New treatments, rapid and inexpensive identification methods, and measures to contain nosocomial transmission and outbreaks are urgently needed.

Mycobacterium abscessus complex comprises a group of rapidly growing, multidrug-resistant, nontuberculous mycobacteria that are responsible for a wide spectrum of skin and soft tissue diseases, central nervous system infections, bacteremia, and ocular and other infections. M. abscessus complex is differentiated into 3 subspecies: M. abscessus subsp. abscessus, M. abscessus subsp. massiliense, and M. abscessus subsp. bolletii. The 2 major subspecies, M. abscessus subsp. abscessus and M.abscessus subsp. massiliense, have different erm(41) gene patterns. This gene provides intrinsic resistance to macrolides, so the different patterns lead to different treatment outcomes. M. abscessus complex outbreaks associated with cosmetic procedures and nosocomial transmissions are not uncommon. Clarithromycin, amikacin, and cefoxitin are the current antimicrobial drugs of choice for treatment. However, new treatment regimens are urgently needed, as are rapid and inexpensive identification methods and measures to contain nosocomial transmission and outbreaks.

Mycobacterium abscessus Complex - a Particular Challenge in the Setting of Lung Transplantation

Mycobacterium abscessus complex is an emerging pathogen in lung transplant candidates and recipients. M. abscessus complex is widespread in the environment and can cause pulmonary, skin and soft tissue, and disseminated infection, particularly in lung transplant recipients. It is innately resistant to many antibiotics making it difficult to treat. Herein we describe the epidemiology, clinical manifestations, diagnosis and treatment of M. abscessus with an emphasis on lung transplant candidates and recipients. We also outline the areas where data are lacking and the areas where further research is urgently needed.

Mycobacterium abscessus Complex Infections in Humans

Mycobacterium abscessus complex comprises a group of rapidly growing, multidrug-resistant, nontuberculous mycobacteria that are responsible for a wide spectrum of skin and soft tissue diseases, central nervous system infections, bacteremia, and ocular and other infections. M. abscessus complex is differentiated into 3 subspecies: M. abscessus subsp. abscessus, M. abscessus subsp. massiliense, and M. abscessus subsp. bolletii. The 2 major subspecies, M. abscessus subsp. abscessus and M. abscessus subsp. massiliense, have different erm(41) gene patterns. This gene provides intrinsic resistance to macrolides, so the different patterns lead to different treatment outcomes. M. abscessus complex outbreaks associated with cosmetic procedures and nosocomial transmissions are not uncommon. Clarithromycin, amikacin, and cefoxitin are the current antimicrobial drugs of choice for treatment. However, new treatment regimens are urgently needed, as are rapid and inexpensive identification methods and measures to contain nosocomial transmission and outbreaks.

Plasma Biomarkers Can Predict Treatment Response in Tuberculosis Patients: A Prospective Observational Study

Despite numerous studies, there has been little progress in the use of biomarkers for predicting treatment response in patients with tuberculosis (TB). Patients with culture-confirmed pulmonary TB between 2010 and 2014 were prospectively recruited. Blood samples were taken upon diagnosis and 2 months after the start of standard anti-TB treatment. A pilot study utilizing measurement of TB-antigen-stimulated cytokines was conducted to select potential biomarkers for further testing. Outcome was defined as persistent culture positivity at 2 months into treatment. Of 167 enrolled patients, 26 had persistent culture positivity. RANTES, IL-22, MMP-8, IL-18, MIG, and Granzyme A were selected as potential biomarkers. For predicting persistent culture positivity, receiver-operating characteristics (ROC) analysis showed that initial RANTES (AUC: 0.725 [0.624-0.827]) and 2-month MMP-8 (AUC: 0.632 [0.512-0.713]) had good discriminative ability. Using a logistic regression model, low initial RANTES level (< 440 pg/mL), initial smear positivity, and high 2-month MMP-8 level (> 3000 pg/mL) were associated with persistent culture positivity. Low initial RANTES level and initial smear positivity had a positive predictive value of 60% (12/20) for persistent culture positivity, compared with 4% (3/75) among patients with high RANTES level and smear negativity upon diagnosis. In the 72 patients with either low RANTES/smear negativity or high RANTES/smear positivity upon diagnosis, the 2-month MMP-8 level had a positive and negative predictive value of 24 and 94%, respectively, for 2-month culture status. Aside from an initial sputum smear status, serum RANTES level at diagnosis and MMP-8 level at 2 months of treatment may be used to stratify risk for culture persistence.

Clinical findings in relation to mortality in non-tuberculous mycobacterial infections: patients with Mycobacterium avium complex have better survival than patients with other mycobacteria

We compared the clinical findings and survival in patients with Mycobacterium avium complex (MAC) and other non-tuberculous mycobacteria (NTM). A total of 167 adult non-human immunodeficiency virus (HIV) patients with at least one positive culture for NTM were included. Medical records were reviewed. The patients were categorised according to the 2007 American Thoracic Society (ATS) criteria. MAC comprised 59 % of all NTM findings. MAC patients were more often female (70 % vs. 34 %, p < 0.001) and had less fatal underlying diseases (23 % vs. 47 %, p = 0.001) as compared to other NTM patients. Symptoms compatible with NTM infection had lasted for less than a year in 34 % of MAC patients but in 54 % of other NTM patients (p = 0.037). Pulmonary MAC patients had a significantly lower risk of death compared to pulmonary other NTM (hazard ratio [HR] 0.50, 95 % confidence interval [CI] 0.33–0.77, p = 0.002) or subgroup of other slowly growing NTM (HR 0.55, 95 % CI 0.31–0.99, p = 0.048) or as rapidly growing NTM (HR 0.47, 95 % CI 0.25–0.87, p = 0.02). The median survival time was 13.0 years (95 % CI 5.9–20.1) for pulmonary MAC but 4.6 years (95 % CI 3.4–5.9) for pulmonary other NTM. Serious underlying diseases (HR 3.21, 95 % CI 2.05–5.01, p < 0.001) and age (HR 1.07, 95 % CI 1.04–1.09, p < 0.001) were the significant predictors of mortality and female sex was a predictor of survival (HR 0.38, 95 % CI 0.24–0.59, p < 0.001) in the multivariate analysis. Pulmonary MAC patients had better prognosis than pulmonary other NTM patients. The symptom onset suggests a fairly rapid disease course.

Impact of pulmonary nontuberculous mycobacterial treatment on pulmonary function tests in patients with and without established obstructive lung disease

BACKGROUND AND OBJECTIVE

There is relatively little data regarding pulmonary function test (PFT) findings and impact of treatment on PFT in pulmonary nontuberculous mycobacterial (pNTM) disease.

METHODS

We performed a retrospective study on pNTM patients. Clinical, radiographical, microbiological and PFT data were reviewed. Patients were divided into three groups based on pre-existing obstructive lung disease: (i) normal (no chronic obstructive pulmonary disease (COPD) or asthma); (ii) asthma; and (iii) COPD. We studied pre-treatment PFT and assessed for PFT changes after anti-mycobacterial therapy.

RESULTS

A total of 96 patients fulfilled ATS disease criteria and had pre-treatment PFT (54 'normal', 18 asthma, 24 COPD). Most common causative NTM was Mycobacterium avium complex (76%), and radiographical disease type was nodular bronchiectasis (71%). Before therapy, all groups had PFT abnormalities, including obstruction, gas trapping and at least mildly low diffusion capacity of carbon monoxide (DLCO). Pre-treatment PFT abnormalities were more pronounced among patients with asthma and COPD. A total of 44 patients had >12 months anti-mycobacterial therapy and post-treatment PFT. There tended to be small and generally not statistically significant reductions in spirometry and DLCO in most groups. Among the nine asthmatic patients, there was a small reduction in residual volume (RV) (1.5% predicted, P = 0.01) and RV/total lung capacity (by 7% predicted, P = 0.06).

CONCLUSIONS

Patients with pNTM have abnormal PFT, and treatment was not associated with substantial changes therein. Asthmatics may experience some improvements in gas trapping after NTM therapy, but because the sample size and the observed change were both small, this requires further investigation.

Nontuberculous mycobacterial infection is associated with increased respiratory failure: a nationwide cohort study

BACKGROUND AND PURPOSE

Population study on relationship between nontuberculous mycobacterial (NTM) infection and respiratory failure (RF) is limited. This study evaluated the RF risk, including acute respiratory failure (ARF), chronic respiratory failure (CRF) and ARF on CRF, in patients with NTM infection in Taiwan.

METHODS

We used the National Health Insurance Research Database of Taiwan to identify 3864 newly diagnosed NTM patients (NTM cohort) from 1999 to 2009, and 15456 non-NTM patients (non-NTM cohort), frequency matched by demographic status for comparison. Incidence and hazard of developing RF were measured by the end of 2010.

RESULTS

The incidence rate of RF was 4.31-fold higher in the NTM cohort than in the non-NTM cohort (44.0 vs.10.2 per 1000 person-years), with an adjusted hazard ratio (HR) of 3.11 (95% CI: 2.73-3.54). The cumulative proportional incidence of RF was 10% higher in the NTM cohort than in the non-NTM cohort (P<0.0001). The RF risk was much greater within 6 months after the diagnosis of NTM infection with a HR of 7.45 (95% CI = 5.50-10.09). Age-specific comparison showed that the younger NTM patients had a higher HR of RF than the elderly NTM patients (HR: 4.42, 95% CI: 3.28-5.96 vs. HR: 2.52, 95% CI: 2.17-2.92). Comorbidity increased the risk of RF in both cohorts, particularly in those with chronic obstructive pulmonary disease.

CONCLUSION

Our study suggests patients with NTM infection are at a high risk of RF. The risk appears much greater soon after patients diagnosed with NTM infection.

Factors associated with quality of life measured by EQ-5D in patients with nontuberculous mycobacterial pulmonary disease

PURPOSE

The impact of pulmonary nontuberculous mycobacterial (pNTM) disease on health-related quality of life (HRQoL) has not received significant attention in the literature. In this study, we compared the HRQoL in patients with pNTM disease and healthy subjects and identified influencing factors using EuroQol 5D (EQ-5D) data.

METHODS

The present study used an age- and sex-matched case-control analysis from a cohort of 85 pNTM patients and 340 participants from a national survey. Baseline EQ-5D utility scores and EQ-5D visual analog scale (VAS) scores were measured in both groups. In patients with pNTM disease, the factors affecting EQ-5D were identified using multiple linear regression analysis.

RESULTS

While the median EQ-5D VAS scores were lower in pNTM patients than in the control subjects (pNTM, 70; control, 80; P < 0.001), the median EQ-5D utility scores were similar in two groups (both, 1.000, P = 0.878). Interestingly, the percentage of subjects reporting problems on the anxiety/depression dimension was higher for patients with pNTM disease (18.8 %) compared with the control subjects (11.5 %, P = 0.07). In multivariate analysis, increasing severity of forced expired volume in one second (FEV1) decline was associated with a significant decrease in EQ-5D scores of pNTM patients.

CONCLUSIONS

This study suggested the EQ-5D may not be useful instrument in pNTM patients due to ceiling effect of EQ-5D and mild disease activity. Patients with pNTM disease tended to report more reduced health status and more problems with anxiety/depression than the healthy controls. Lung function, measured by FEV1, was independently associated with EQ-5D scores in patients with pNTM disease.

Nontuberculosis mycobacterium disease is a risk factor for chronic obstructive pulmonary disease: a nationwide cohort study

BACKGROUND

The aim of this study was to evaluate the association between chronic obstructive pulmonary disease (COPD) and nontuberculosis mycobacterium (NTM) disease.

METHODS

We used data from the National Health Insurance Research Database of Taiwan in this study. The NTM cohort contained 3,005 patients, and each case was randomly frequency matched by age, sex, income, occupation, and index year with four people from the general population without NTM infections. Multivariate Cox proportional hazards regression was used to calculate adjusted hazard ratios (aHR) of COPD in the NTM cohort compared with the non-NTM cohort.

RESULTS

The incidence of COPD was 3.08-fold higher (21.75 vs. 6.11 per 1,000 person-years) in the NTM cohort than in the non-NTM cohort. The aHR of COPD comparing the NTM cohort with the non-NTM cohort was 3.57 (95 % CI 2.56-4.97) for women and 2.89 (95 % CI 2.31-3.61) for men. The aHR of COPD was higher in the patients with NTM infection and a comorbidity such as bronchopneumonia, pneumonia, diabetes, asthma, and heart disease. The Mycobacterium avium-intracellulare complex group (MAC) and the non-MAC group were isolated in the NTM cohort. The MAC group had a higher aHR of COPD than the non-NTM cohort (aHR = 3.72, 95 % CI 2.94-4.72). The cumulative incidence of COPD in the NTM cohort was higher than in the non-NTM cohort (P < 0.0001, log rank test).

CONCLUSIONS

Physicians should be aware of indolent NTM disease that increases the risk of COPD.

Nutritional indicators are correlated with the radiological severity score in patients with Mycobacterium avium complex pulmonary disease: a cross-sectional study

OBJECTIVE

Body weight loss in patients with Mycobacterium avium complex (MAC) pulmonary disease can be fatal. The administration of nutritional supplements should be an important component in the treatment of this disease. Objective data regarding the association between the nutritional status and disease severity have not been reported. This cross-sectional study aimed to compare the nutritional status and radiological severity scores in MAC pulmonary disease patients.

METHODS

We retrospectively reviewed the records of 40 patients who were admitted to our institution for the treatment of MAC pulmonary disease between July 2008 and July 2010. Nutritional indices, including the ideal body weight ratio, triceps skinfold, mid-upper arm muscle circumference, and percentage of predicted resting energy expenditure, were compared with the radiological severity scores. Quantitative values of the extent of nodules, infiltration shadows, cavities, and bronchiectasis on the computed tomography scans were used to evaluate the radiological severity scores.

RESULTS

The patients suffered from a significantly decreased percentage of ideal body weight, body fat and muscle mass. The average radiological score was 17.6±8.4 points. The percentage of ideal body weight (p<0.001), percentage of triceps skinfold (p<0.001) and percentage of mid-upper arm muscle circumference (p<0.002) were negatively correlated with the radiological scores, while the percentage of the predicted resting energy expenditure (p<0.001) was positively correlated with the scores.

CONCLUSION

A poor nutritional status is common in patients with progressive MAC pulmonary disease, which supports the hypothesis that aggressive nutritional interventions are indicated in the treatment of this disease.