Isoniazid resistance and death in patients with tuberculous meningitis: retrospective cohort study

Objective To determine whether initial isoniazid resistance is associated with death during the treatment of tuberculous meningitis

Assessing Response to Therapy for Nontuberculous Mycobacterial Lung Disease: Quo Vadis?

Assessing progression of disease or response to treatment remains a major challenge in the clinical management of nontuberculous mycobacterial (NTM) infections of the lungs. Serial assessments of validated measures of treatment response address whether the current therapeutic approach is on track toward clinical cure, which remains a fundamental question for clinicians and patients during the course of NTM disease treatment. The 2015 NTM Research Consortium Workshop, which included a patient advisory panel, identified treatment response biomarkers as a priority area for investigation. Limited progress in addressing this challenge also hampers drug development efforts. The Biomarker Qualification Program at the FDA supports the use of a validated treatment response biomarker across multiple drug development programs. Current approaches in clinical practice include microbiologic and radiographic monitoring, along with symptomatic and quality-of-life assessments. Blood-based monitoring, including assessments of humoral and cell-mediated NTM-driven immune responses, remain under investigation. Alignment of data collection schemes in prospective multicenter studies, including the support of biosample repositories, will support identification of treatment response biomarkers under standard-of-care and investigational therapeutic strategies. In this review, we outline the role of treatment monitoring biomarkers in both clinical practice and drug development frameworks

Isoniazid Toxicity among an Older Veteran Population: A Retrospective Cohort Study

Background: our objective was to determine the incidence of toxicity among veterans initiating isoniazid therapy for latent tuberculosis infection (LTBI) and determine whether advancing age was a risk factor for toxicity. Methods: we performed a retrospective cohort study among all adults initiating isoniazid treatment for LTBI at a Veterans Medical Center from 1999 to 2005. We collected data on patient demographics, co-morbidities, site of initiation, and treatment outcome. Results: 219 patients initiated isoniazid therapy for LTBI during the period of observation, and the completion of therapy was con�rmed in 100 patients (46%). Among 18/219 patients (8%) that discontinued therapy due to a documented suspected toxicity, the median time to onset was 3 months (IQR 1-5 months). In an adjusted Cox regression model, there was no association between discontinuation due to suspected toxicity and advancing age (HR 1.03, 95% CI 0.99, 1.07). In contrast, hepatitis C infection was a signi�cant predictor of cessation due to toxicity in the adjusted analysis (HR 3.03, 95% CI 1.08, 8.52). Conclusions: cessation of isoniazid therapy due to suspected toxicity was infrequently observed among a veteran population and was not associated with advancing age. Alternative LTBI treatment approaches should be further examined in the veteran population

First Use of Multiple Imputation with the National Tuberculosis Surveillance System

Aims. The purpose of this study was to compare methods for handling missing data in analysis of the National Tuberculosis Surveillance System of the Centers for Disease Control and Prevention. Because of the high rate of missing human immunodeficiency virus (HIV) infection status in this dataset, we used multiple imputation methods to minimize the bias that may result from less sophisticated methods. Methods. We compared analysis based on multiple imputation methods with analysis based on deleting subjects with missing covariate data from regression analysis (case exclusion), and determined whether the use of increasing numbers of imputed datasets would lead to changes in the estimated association between isoniazid resistance and death. Results. Following multiple imputation, the odds ratio for initial isoniazid resistance and death was 2.07 (95% CI 1.30, 3.29); with case exclusion, this odds ratio decreased to 1.53 (95% CI 0.83, 2.83). The use of more than 5 imputed datasets did not substantively change the results. Conclusions. Our experience with the National Tuberculosis Surveillance System dataset supports the use of multiple imputation methods in epidemiologic analysis, but also demonstrates that close attention should be paid to the potential impact of missing covariates at each step of the analysis

Adipose Tissue Regulates Pulmonary Pathology during TB Infection

Although the lungs are the port of entry and the predominant site of TB disease manifestation, we and others have demonstrated that M. tuberculosis also persists in adipose tissue of aerosol-infected animals and directly or indirectly alters adipose tissue physiology, which in turn alters whole-body immuno-metabolic homeostasis. Our present report demonstrates a direct effect of loss of adipocytes (fat cells) on promoting the severity of pulmonary pathogenesis during TB, advancing our understanding of the pathogenic interactions between wasting and TB activation/reactivation.Tuberculosis (TB), caused by Mycobacterium tuberculosis infection, remains a major cause of mortality and morbidity worldwide. One-third of the world population is infected with M. tuberculosis, and about 15 million people with latent tuberculosis infection (LTBI) reside in the United States. An estimated 10% of individuals with LTBI are at risk of progressing to active disease. Loss of body mass, or wasting, accompanied by a significant reduction of body fat is often associated with active TB disease and is considered to be immunosuppressive and a major determinant of severity and outcome of disease. While the lungs are the primary site of M. tuberculosis infection and TB manifestation, recent reports have shown that adipose tissue serves as an important reservoir for M. tuberculosis. In this article, we investigated the association between M. tuberculosis infection, adipose tissue, and TB disease progression using a transgenic inducible “fatless” model system, the FAT-ATTAC (fat apoptosis through targeted activation of caspase 8) mouse. By selectively ablating fat tissue during M. tuberculosis infection, we directly tested the role of fat cell loss and adipose tissue physiology in regulating pulmonary pathology, bacterial burden, and immune status. Our results confirm the presence of M. tuberculosis in fat tissue after aerosol infection of mice and show that loss of fat cells is associated with an increase in pulmonary M. tuberculosis burden and pathology. We conclude that acute loss of adipose tissue during LTBI may predispose the host to active TB disease

A Pilot Study of Immune Activation and Rifampin Absorption in HIV-Infected Patients without Tuberculosis Infection: A Short Report

Background. Rifampin malabsorption is frequently observed in tuberculosis patients coinfected with human immunodeficiency virus (HIV) but cannot be predicted by patient factors such as CD4+ T cell count or HIV viral load. Methods. We sought to describe the relationship between HIV-associated immune activation, measures of gut absorptive capacity and permeability, and rifampin pharmacokinetic parameters in a pilot study of 6 HIV-infected, tuberculosis-uninfected patients who were naïve to antiretroviral therapy. Results. The median rifampin area under the concentration-versus-time curve during the 8-hour observation period was 42.8 mg·hr/L (range: 21.2 to 57.6), with a median peak concentration of 10.1 mg/L (range: 5.3 to 12.5). We observed delayed rifampin absorption, with a time to maximum concentration greater than 2 hours, in 2 of 6 participants. There was a trend towards increased plasma concentrations of sCD14, a marker of monocyte activation in response to bacterial translocation, among participants with delayed rifampin absorption compared to participants with rapid absorption (p=0.06). Conclusions. Delayed rifampin absorption may be associated with elevated markers of bacterial translocation among HIV-infected individuals naïve to antiretroviral therapy. This trial is registered with NCT01845298

Guidelines-based treatment associated with improved economic outcomes in nontuberculous mycobacterial lung disease

Background: The prevalence of nontuberculous mycobacterial lung disease (NTMLD) in the US has increased; however, data characterizing the associated healthcare utilization and expenditure at the national level are limited. Objective: To examine associations between economic outcomes and the use of anti-Mycobacterium avium complex (MAC) guidelines-based treatment (GBT) for newly-diagnosed NTMLD in a US national managed care claims database (Optum ® Clinformatics ® Data Mart). Methods: NTMLD was defined as having ≥2 claims for NTMLD (ICD-9 031.0; ICD-10 A31.0) on separate occasions ≥30 days apart (between 2007 and 2016). The cohort included patients insured continuously over a period of at least 36 months (12 months before initial NTMLD diagnostic claim and for the subsequent 24 months). Treatment was classified as GBT (consistent with American Thoracic Society/Infectious Diseases Society of America guidelines), non-GBT, or untreated. All-cause hospitalization rates and total healthcare expenditures at Year 2 were assessed as outcomes of the treatment prescribed in Year 1 after NTMLD diagnosis. Results: A total of 1,039 patients met study criteria for NTMLD (GBT, n = 294; non-GBT, n = 298; untreated, n = 447). After adjustment for baseline characteristics, GBT was associated with a significantly lower all-cause hospitalization risk vs non-GBT (odds ratio [OR] = 0.53; 95% CI = 0.33-0.85, p = 0.008), and vs being untreated (OR = 0.57; 95% CI = 0.35-0.91, p = 0.020). Adjusted total healthcare expenditure in Year 2 with GBT ($69,691) was lower than that with non-GBT ($77,624) with a difference of −$7,933 (95$14,968 to −$899; p = 0.03). Conclusions: Patients with NTMLD in a US managed care claims database who were prescribed GBT had lower hospitalization risk than those who were prescribed non-GBT or were untreated. GBT was associated with lower total healthcare expenditure compared with non-GBT