Factors associated with diabetes in tuberculosis patients in Harris County, Texas 1995--2004

Objective. To determine the prevalence and factors associated with diabetes in tuberculosis patients in Harris County, Texas. ^ Background. Tuberculosis and diabetes mellitus are two diseases of immense public health significance. Various epidemiologic studies have established an association between the two conditions. While many studies have identified factors associated with the conditions individually, few have looked at factors associated with their co-occurrence particularly in the United States. Furthermore, most of those studies are hospital-based and may not be representative of the population. The aim of this study was to determine the prevalence and distribution of diabetes among tuberculosis patients in Harris County, Texas and to identify the factors associated with diabetes in tuberculosis. ^ Methods. A population-based case control study was performed using secondary data from the Houston Tuberculosis Initiative (HTI) collected from October 1995 to September 2004. Socio-demographic characteristics and clinical variables were compared between tuberculosis patients with diabetes and non-diabetic tuberculosis patients. Logistic regression analysis was performed to identify associations. Survival at 180 days post tuberculosis diagnosis was assessed by Cox regression. ^ Results. The prevalence of diabetes among the tuberculosis (TB) population was 14.4%. The diabetics (cases) with a mean age 53 ± 13.3 years were older than the non-diabetics (controls) with a mean age of 39 ± 18.5 years (p<0.001). Socio-demographic variables that were independently associated with the risk of diabetes were age (OR 1.04, p<0.001) and Hispanic ethnicity (OR 2.04, p<0.001). Diabetes was associated with an increased risk of pulmonary tuberculosis disease (OR 1.33, p<0.028). Among individuals with pulmonary TB, diabetes was associated with positive sputum acid-fast bacilli (AFB) smear (OR 1.47, p<0.005) and culture (OR 1.83, p<0.018). Diabetics were more likely to have cavitary lung disease than non-diabetics (OR 1.50, p<0.002). After adjustment for age and HIV status, the risk of dying within 180 days of TB diagnosis was significantly increased in the diabetics (HR 1.51, p<0.002). ^ Conclusion. Diabetes mellitus was more prevalent in our tuberculosis patients than in the general population. The tuberculous diabetic may be more infectious and has a higher risk of death. It is therefore imperative to screen diabetics for TB and TB patients for diabetes. ^

A retrospective analysis of patients referred for tuberculosis testing at Parkland Hospital, Dallas, TX

Tuberculosis (TB) is an infectious disease of great public health importance, particularly to institutions that provide health care to large numbers of TB patients such as Parkland Hospital in Dallas, TX. The purpose of this retrospective chart review was to analyze differences in TB positive and TB negative patients to better understand whether or not there were variables that could be utilized to develop a predictive model for use in the emergency department to reduce the overall number of suspected TB patients being sent to respiratory isolation for TB testing. This study included patients who presented to the Parkland Hospital emergency department between November 2006 and December 2007 and were isolated and tested for TB. Outcome of TB was defined as a positive sputum AFB test or a positive M. tuberculosis culture result. Data were collected utilizing the UT Southwestern Medical Center computerized database OACIS and included demographic information, TB risk factors, physical symptoms, and clinical results. Only two variables were significantly (P<0.05) related to TB outcome: dyspnea (shortness of breath) (P<0.001) and abnormal x-ray (P<0.001). Marginally significant variables included hemoptysis (P=0.06), weight loss (P=0.11), night sweats (P=0.20), history of homelessness or incarceration (P=0.15), and history of positive skin PPD (P=0.19). Using a combination of significant and marginally significant variables, a predictive model was designed which demonstrated a specificity of 24% and a sensitivity of 70%. In conclusion, a predictive model for TB outcome based on patients who presented to the Parkland Hospital emergency department between November 2006 and December 2007 was unsuccessful given the limited number of variables that differed significantly between TB positive and TB negative patients. It is suggested that a future prospective cohort study should be implemented to collect data on TB positive and TB negative patients. It may be possible that a more thorough prospective collection of data may lead to clearer comparisons between TB positive and TB negative patients and ultimately to the design of a more sensitive predictive model for TB outcome. ^

Does exhaled nitric oxide predict asthma exacerbation in children?

Asthma is a chronic complex disorder of the respiratory tract that affects millions of people globally, a large percentage of which are children. Triggered by a host of factors such as allergens and changes in temperature, the pathophysiologic and clinical indices vary among patients and have contributed to difficulties in overall management of asthma. Shortly after exhaled nitric oxide (eNO) was discovered in higher concentrations in asthma patients, it was shown to be superior to other markers such as PEFR, FEV1 and sputum eosinophils in screening asthma patients. Studies have also noted promising results regarding the use of eNO to predict asthma exacerbation in adults while in children, asthma symptoms have been observed to be good predictors of asthma exacerbation. Currently however, the potential of eNO as a predictor of asthma exacerbation in children is yet to be examined. The objective of this study was to assess eNO potential to predict asthma exacerbation in children by examining the relationship between eNO and changes in pulmonary function, asthma symptoms and rescue medication use.^ The primary study "Air Toxics and Asthma in Children" (ATAC), recruited children aged 9 to 14 years with labile persistent asthma diagnosed at least one year earlier. The data obtained from 30 study participants, included exhaled nitric oxide concentration, PEFR, FEV1, asthma symptoms and frequency of emergency medication use.^ Descriptive statistics, Pearson's and Spearman's correlation tests were followed by a simple linear regression in which eNO was the independent (predictor) variable while FEV1, PEFR, asthma symptoms and frequency of emergency medication use were the dependent (outcome) variables.^ Results showed that eNO was associated with percent change in FEV1, day time wheeze, night time shortness of breath, but correlated only weakly with PEFR, amplitude percent of mean PEFR, FEV1, percent change in FEV1 and asthma symptoms.^ Further research is imperative to better define the role of eNO and understand intrinsic pathologic mechanisms towards asthma management in children.^

Evaluation of the T-SPOT(RTM).TB test in the diagnosis of latent tuberculosis infection in HIV-infected children in Uganda

Background. About a third of the world’s population is infected with tuberculosis (TB) with sub-Saharan Africa being the worst hit. Uganda is ranked 16th among the countries with the biggest TB burden. The burden in children however has not been determined. The burden of TB has been worsened by the advent of HIV and TB is the leading cause of mortality in HIV infected individuals. Development of TB disease can be prevented if TB is diagnosed during its latent stage and treated with isoniazid. For over a century, latent TB infection (LTBI) was diagnosed using the Tuberculin Skin Test (TST). New interferon gamma release assays (IGRA) have been approved by FDA for the diagnosis of LTBI and adult studies have shown that IGRAs are superior to the TST but there have been few studies in children especially in areas of high TB and HIV endemicity. ^ Objective. The objective of this study was to examine whether the IGRAs had a role in LTBI diagnosis in HIV infected children in Uganda. ^ Methods. Three hundred and eighty one (381) children were recruited at the Baylor College of Medicine-Bristol Meyers Squibb Children’s Clinical Center of Excellence at Mulago Hospital, Kampala, Uganda between March and August 2010. All the children were subjected to a TST and T-SPOT ®.TB test which was the IGRA chosen for this study. Sputum examination and chest x-rays were also done to rule out active TB. ^ Results. There was no statistically significant difference between the tests. The agreement between the two assays was 95.9% and the kappa statistic was 0.7 (95% CI: 0.55–0.85, p-value<0.05) indicating a substantial or good agreement. The TST was associated with older age and higher weight for age z-scores but the T-SPOT®. TB was not. Both tests were associated with history of taking anti-retroviral therapy (ART). ^ Conclusion. Before promoting use of IGRAs in children living in HIV/TB endemic countries, more research needs to be done. ^

Tuberculosis in HIV-infected individuals in Ho Chi Minh City, Vietnam

Early and accurate detection of TB disease in HIV-infected individuals is a critical step for a successful TB program. In Vietnam, the diagnosis of TB disease, which is based predominantly on the clinical examination, chest radiography (CXR) and acid fast bacilli (AFB) sputum smear, has shown to be of low sensitivity in immunocompromised patients. The sputum culture is not routinely performed for patients with AFB negative smears, even in HIV-infected individuals.^ In that background, we conducted this cross-sectional study to estimate the prevalence of sputum culture-confirmed pulmonary tuberculosis (PTB), smear-negative PTB, and multidrug-resistant TB (MDR-TB) in the HIV-infected population in Ho Chi Minh City (HCMC), the largest city in Vietnam where both TB and HIV are highly prevalent. We also evaluated the diagnostic performance of various algorithms based on routine available tools in Vietnam such as symptoms screening, CXR, and AFB smear. Nearly 400 subjects were consecutively recruited from HIV-infected patients seeking care at the An Hoa Clinic in District 6 of Ho Chi Minh City from August 2009 through June 2010. Participants’ demographic data, clinical status, CXR, and laboratory results were collected. A multiple logistic regression model was developed to assess the association of covariates and PTB. ^ The prevalence of smear-positive TB, smear-negative TB, resistant TB, and MDR-TB were 7%, 2%, 5%, 2.5%, and 0.3%, respectively. Adjusted odds ratios for low CD4+ cell count, positive sputum smear, and CXR to positive sputum culture were 3.17, 32.04, and 4.28, respectively. Clinical findings alone had poor sensitivity, but the combination of CD4+ cell count, sputum smear, and CXR proved to perform a more accurate diagnosis.^ This study results support the routine use of sputum culture to improve the detection of TB disease in HIV-infected individuals in Vietnam. When routine sputum culture is not available, an algorithm combining CD4+ cell count, sputum smear, and CXR is recommended for diagnosing PTB. Future studies on more affordable, rapid, and accurate tests for TB infection would also be necessary to timely provide specific treatments for patients in need, reduce mortality, and minimize TB transmission to the general population.^