Allan Chiunda

Case Western Reserve University School of Medicine , Cleveland, Ohio, United States

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Publications (10)32.68 Total impact

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    ABSTRACT: We assessed the impact of wasting on survival in patients with tuberculosis by using a precise height-normalized lean tissue mass index (LMI) estimated by bioelectrical impedance analysis and body mass index (BMI). In a retrospective cohort study, 747 adult pulmonary patients with tuberculosis who were screened for HIV and nutritional status were followed for survival. Of 747 patients, 310 had baseline wasting by BMI (kg/m(2)) and 103 by LMI (kg/m(2)). Total deaths were 105. Among men with reduced BMI, risk of death was 70% greater (hazard ratio [HR] 1.7, 95% confidence interval [95% CI] 1.03-2.81) than in men with normal BMI. Survival did not differ by LMI among men (HR 1.1; 95% CI 0.5-2.9). In women, both the BMI and LMI were associated with survival. Among women with reduced BMI, risk of death was 80% greater (HR 1.8; 95% CI 0.9-3.5) than in women with normal BMI; risk of death was 5-fold greater (HR 5.0; 95% CI 1.6-15.9) for women with low LMI compared with women with normal LMI. Wasting assessed by reduced BMI is associated with an increased risk for death among both men and women whereas reduced LMI is among women with tuberculosis.
    Annals of epidemiology 05/2012; 22(7):466-73. · 2.95 Impact Factor
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    ABSTRACT: Tuberculosis is an ancient disease that continues to threaten individual and public health today, especially in sub-Saharan Africa. Current surveillance systems describe general risk of tuberculosis in a population but do not characterize the risk to an individual following exposure to an infectious case. In a study of household contacts of infectious tuberculosis cases (n = 1918) and a community survey of tuberculosis infection (N = 1179) in Kampala, Uganda, we estimated the secondary attack rate for tuberculosis disease and tuberculosis infection. The ratio of these rates is the likelihood of progressive primary disease after recent household infection. The secondary attack rate for tuberculosis disease was 3.0% (95% confidence interval: 2.2, 3.8). The overall secondary attack rate for tuberculosis infection was 47.4 (95% confidence interval: 44.3, 50.6) and did not vary widely with age, HIV status or BCG vaccination. The risk for progressive primary disease was highest among the young or HIV infected and was reduced by BCG vaccination. Early case detection and treatment may limit household transmission of M. tuberculosis. Household members at high risk for disease should be protected through vaccination or treatment of latent tuberculosis infection.
    PLoS ONE 01/2011; 6(2):e16137. · 3.53 Impact Factor
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    ABSTRACT: The purpose of this study was to summarise the current state of healthcare quality improvement literature focusing on sub-Saharan Africa. Conventional methods of searching the literature were quickly found to be inadequate or inappropriate, given the different needs of practitioners in sub-Saharan Africa, and the inaccessibility of the literature. The group derived a core list of what were deemed exemplary quality improvement articles, based on consensus and a search into the "grey" literature of quality improvement. Quality improvement articles from sub-Saharan Africa are difficult to find, and suffer from a lack of centrality and organisation of literature. Efforts to address this are critical to fostering the growth of quality improvement literature in developing country settings.
    Quality and Safety in Health Care 10/2010; 19(5):416-9. · 2.16 Impact Factor
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    Journal of Health Services Research & Policy 07/2010; 15(3):185-7. · 1.73 Impact Factor
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    ABSTRACT: We determined whether human immunodeficiency virus (HIV) infection affects body cell mass and fat mass wasting among adults with pulmonary tuberculosis (PTB). We screened 967 Ugandan adults for PTB and HIV infection in a cross-sectional study. We compared anthropometric and bioelectric impedance analysis (BIA) body composition parameters among HIV-seropositive and HIV-seronegative men and women with or without PTB by using a non-parametric test. We found that poor nutritional status associated with TB differed among men and women. Anthropometric and BIA body composition did not differ between HIV-seropositive and HIV-seronegative patients regardless of gender. Average weight group difference in men consisted of body cell mass and fat mass in equal proportions of 43%. In women, average weight group difference consisted predominantly of fat mass of 73% and body cell mass of 13%. Compared to individuals without TB, patients with TB had lower body mass index, weight, body cell mass, and fat mass regardless of gender and HIV status. Gender, but not HIV status, was associated with body composition changes in TB. TB appears to be the dominant factor driving the wasting process among co-infected patients.
    Annals of epidemiology 03/2010; 20(3):210-6. · 2.95 Impact Factor
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    ABSTRACT: Tuberculosis (TB) is a growing public health threat globally and several studies suggest a role of host genetic susceptibility in increased TB risk. As part of a household contact study in Kampala, Uganda, we have taken a unique approach to the study of genetic susceptibility to TB by developing an intermediate phenotype model for TB susceptibility, analyzing levels of tumor necrosis factor-alpha (TNFalpha) in response to culture filtrate as the phenotype. In the present study, we analyzed candidate genes related to TNFalpha regulation and found that interleukin (IL)-10, interferon-gamma receptor 1 (IFNGR1), and TNFalpha receptor 1 (TNFR1) genes were linked and associated to both TB and TNFalpha. We also show that these associations are with progression to active disease and not susceptibility to latent infection. This is the first report of an association between TB and TNFR1 in a human population and our findings for IL-10 and IFNGR1 replicate previous findings. By observing pleiotropic effects on both phenotypes, we show construct validity of our intermediate phenotype model, which enables the characterization of the role of these genetic polymorphisms on TB pathogenesis. This study further illustrates the utility of such a model for disentangling complex traits.
    Human Genetics 08/2007; 121(6):663-73. · 4.63 Impact Factor
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    ABSTRACT: To determine immunologic and epidemiologic correlates of acute Mycobacterium tuberculosis infection in household contacts of infectious tuberculosis cases, we performed a prospective, community-based cohort study of index cases and their household contacts in Kampala, Uganda. Contacts were evaluated for tuberculin skin test (TST) conversion over two years. Interferon-gamma expression was measured using a whole blood assay after stimulating with M. tuberculosis culture-filtrate. In 222 contacts with a TST less than 5 mm at baseline, the one-year rate of TST conversion was 27%. The TST conversion was associated with the infectiousness of the index case and proximity of contact. Interferon-gamma levels at baseline were greater among TST converters compared with those who did not convert. The risk of TST conversion increased four-fold as the baseline interferon-gamma increased 10-fold, but only in contacts with BCG vaccination. In household contacts of tuberculosis, interferon-gamma responses to non-specific mycobacterial antigens may be used to make an early diagnosis of tuberculosis infection, especially in resource-limited settings where bacille Calmette-Guérin vaccination is commonly used.
    The American journal of tropical medicine and hygiene 08/2006; 75(1):55-61. · 2.53 Impact Factor
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    ABSTRACT: Tuberculosis (TB) is a growing global public health problem. Several studies suggest a role for host genetics in disease susceptibility, but studies to date have been inconsistent and a comprehensive genetic model has not emerged. A limitation of previous genetic studies is that they only analyzed the binary trait TB, which does not reflect disease heterogeneity. Furthermore, these studies have not accounted for the influence of shared environment within households on TB risk, which may spuriously inflate estimates of heritability. We conducted a household contact study in a TB-endemic community in Uganda. Antigen-induced tumor necrosis factor-alpha (TNFalpha) expression, a key component of the underlying immune response to TB, was used as an endophenotype for TB. Path analysis, conducted to assess the effect of shared environment, suggested that TNFalpha is heritable (narrow sense heritability = 34-66%); the effect of shared environment is minimal (1-14%), but gene-environment interaction may be involved. Segregation analysis of TNFalpha suggested a major gene model that explained one-third of the phenotypic variance, and provided putative evidence of natural selection acting on this phenotype. Our data further support TNFalpha as an endophenotype for TB, as it may increase power to detect disease-predisposing loci.
    Human Heredity 02/2005; 60(2):109-18. · 1.57 Impact Factor
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    ABSTRACT: Tuberculosis remains a serious threat to public health, especially in sub-Saharan Africa. To determine the host and environmental factors responsible for tuberculosis in African households, the authors performed a prospective cohort study of 1,206 household contacts of 302 index cases with tuberculosis enrolled in Uganda between 1995 and 1999. All contacts were systematically evaluated for active tuberculosis and risk factors for active disease. Among the 1,206 household contacts, 76 secondary cases (6%) of tuberculosis were identified. Of these cases, 51 were identified in the baseline evaluation, and 25 developed during follow-up. Compared with index cases, secondary cases presented more often with minimal disease. The risk for secondary tuberculosis was greater among young children than adults (10% vs. 1.9%) and among human immunodeficiency virus-seropositive than -seronegative contacts (23% vs. 3.3%). Host risk factors could not be completely separated from the effects of environmental risk factors, suggesting that a household may represent a complex system of interacting risks for tuberculosis.
    American Journal of Epidemiology 12/2003; 158(9):887-98. · 4.78 Impact Factor
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    ABSTRACT: The timely evaluation of new drugs that can be used to shorten tuberculosis (TB) treatment will require surrogate markers for relapse. This study examined bactericidal activity against intracellular Mycobacterium tuberculosis in whole blood culture (whole blood bactericidal activity; WBA) during TB treatment. In the absence of chemotherapy, immune mechanisms in patient blood resulted in bacteriostasis, whereas administration of oral chemotherapy resulted in bacillary killing. Total WBA per dose was greater during the intensive phase of treatment than during the continuation phase (mean, -2.32 vs. -1.67 log(10) cfu-days, respectively; P<.001). Cumulative WBA throughout treatment was greater in subjects whose sputum cultures converted to negative by the eighth week of treatment than in those for whom conversion was delayed (mean, -365 vs. -250 log(10) cfu-days; P=.04) and correlated with the rate of decrease of sputum colony-forming unit counts during the first 4 weeks of treatment (P=.018), both of which are indicative of prognosis. These findings indicate that measurement of WBA may have a role in assessing the sterilizing activity of new anti-TB drugs.
    The Journal of Infectious Diseases 01/2003; 187(2):270-8. · 5.85 Impact Factor