Factors affecting in-hospital mortality of non-tuberculous mycobacterial pulmonary disease

The Study of Associated Factors for Non-Tuberculous Mycobacterial Pulmonary Disease Compared to Pulmonary Tuberculosis: A Propensity Score Matching Analysis

Objective

Investigate the differences in clinical manifestations, imaging features, and associated inflammatory markers between Nontuberculous Mycobacterial Pulmonary Disease (NTM-PD) and Pulmonary Tuberculosis (PTB), identify potential risk factors for NTM-PD, and establish a logistic regression model to evaluate its diagnostic value.

Methods

Baseline data were collected from 145 patients with NTM-PD and 206 patients with PTB. Propensity score matching (PSM) was utilized to achieve a 1:1 match between the two groups, resulting in 103 matched pairs. The differences in comorbidities, imaging features, and inflammatory markers were compared between the two groups. Multivariate binary logistic regression analysis was conducted to identify independent influencing factors, and the diagnostic value of the established model was evaluated.

Results

After matching, significant differences were observed between the NTM-PD group and the PTB group in terms of diabetes, bronchiectasis, chronic obstructive pulmonary disease(COPD), cystic and columnar changes, lung cavity presentation, and monocyte percentage (MONO%), lymphocyte count (LYMPH#), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) (P<0.05). Logistic regression analysis confirmed that diabetes, bronchiectasis, COPD, and lung cavities were risk factors for NTM-PD. The established regression analysis model was analyzed by the Receiver Operating Characteristic (ROC) curve, the Area Under the Curve (AUC) was obtained as 0.795 (P<0.001, 95% CI 0.734-0.857). At a Youden index of 0.505, the sensitivity was 84.5% and the specificity was 66.6%. The Hosmer-Lemeshow test was used to evaluate the model's calibration, with a chi-square value of 11.023 and P=0.200>0.05, indicating no significant difference between predicted and observed values.

Conclusion

For patients without diabetes but with bronchiectasis, COPD, and imaging characteristics of lung cavities, a high level of vigilance and active differential diagnosis for NTM-PD should be exercised. Given that the clinical manifestations of NTM-PD are similar to those of PTB, a detailed differential diagnosis is necessary during the diagnostic process to avoid misdiagnosis.

Protein-energy restriction-induced lipid metabolism disruption causes stable-to-progressive disease shift in Mycobacterium avium-infected female mice

BACKGROUND

Disease susceptibility and progression of Mycobacterium avium complex pulmonary disease (MAC-PD) is associated with multiple factors, including low body mass index (BMI). However, the specific impact of low BMI on MAC-PD progression remains poorly understood. This study aims to examine the progression of MAC-PD in the context of low BMI, utilising a disease-resistant mouse model.

METHODS

We employed a MAC infection-resistant female A/J mouse model to compare the progression of MAC-PD under two dietary conditions: one group was fed a standard protein diet, representing protein-energy unrestricted conditions, and the other was fed a low protein diet (LPD), representing protein-energy restriction.

FINDINGS

Our results reveal that protein-energy restriction significantly exacerbates MAC-PD progression by disrupting lipid metabolism. Mice fed an LPD showed elevated fatty acid levels and related gene expressions in lung tissues, similar to findings of increased fatty acids in the serum of patients who exhibited the MAC-PD progression. These mice also exhibited increased CD36 expression and lipid accumulation in macrophages upon MAC infection. In vitro experiments emphasised the crucial role of CD36-mediated palmitic acid uptake in bacterial proliferation. Importantly, in vivo studies demonstrated that administering anti-CD36 antibody to LPD-fed A/J mice reduced macrophage lipid accumulation and impeded bacterial growth, resulting in remarkable slowing disease progression.

INTERPRETATION

Our findings indicate that the metabolic status of host immune cells critically influences MAC-PD progression. This study highlights the potential of adequate nutrient intake in preventing MAC-PD progression, suggesting that targeting CD36-mediated pathways might be a host-directed therapeutic strategy to managing MAC infection.

FUNDING

This research was funded by the National Research Foundation of Korea, the Korea Research Institute of Bioscience and Biotechnology, and the Korea National Institute of Health.

Pulmonary complications of eating disorders: a literature review

The medical complications of eating disorders (EDs) have been described in the literature; however, the pulmonary system has historically been described as relatively spared from the ravages of eating disorders and thus neglected in the literature. Here we review the pulmonary complications that have been described in the literature, including the effects of starvation on the lungs of nutritionally deprived animals and patients with anorexia nervosa. There is clear evidence of weakness of respiratory muscles with starvation in both groups. However, there is discordance in the literature as to whether starvation results in "nutritional emphysema," and if so, by what mechanism and at what degree of malnutrition it develops. We also explore the growing concern for the risk of non-tuberculosis mycobacterium infection as well as risk for pneumomediastinum and pneumothorax in patients with restrictive EDs. From the limited literature, it is clear the lungs, in fact, are not spared and that further research is needed to fully understand the full extent of pulmonary complications instigated by EDs.