The effect of partner HIV status on motivation to take antiretroviral and isoniazid preventive therapies: a conjoint analysis. (2018). Kim HY., Hanrahan CF., Dowdy DW., Martinson N., Golub J., Bridges JFP, AIDS care, 30, 1298-1305
Antiretroviral therapy (ART) and isoniazid preventive therapy (IPT) are important to reduce morbidity and mortality among people newly diagnosed of HIV. The successful uptake of ART and IPT requires a comprehensive understanding of patients' motivation to take such therapies. Partners also play an important role in the decision to be initiated and retained in care. We quantified patients' motivation to take preventive therapies (ART and IPT) and compared by partner HIV status among people newly diagnosed of HIV. We enrolled and surveyed adults (≥18 years) with a recent HIV diagnosis (<6 months) from 14 public primary care clinics in Matlosana, South Africa. Participants received eight forced-choice tasks comparing two mutually exclusive sub-sets of seven possible benefits related to preventive therapies. A linear probability model was fitted to estimate the probability of prioritizing each benefit. Tests of concordance were conducted across partner HIV status (no partner, HIV- or unknown, or HIV+). A total of 424 people completed surveys. At the time of interview, 272 (64%) were on ART and 334 (79%) had a partner or spouse. Keeping themselves healthy for their family was the most important motivator to take preventive therapies (p < 0.001). Preventing HIV transmission to partners was also highly prioritized among participants with current partners independent of partner's HIV status (p < 0.001), but it was least prioritized among those without current partners (p = 0.72). Keeping themselves healthy was less prioritized. We demonstrate that social responsibility such as supporting family and preventing HIV transmission to partners may pose greater motivation for ART and IPT initiation and adherence compared to individual health benefits. These messages should be emphasized to provide effective patient-centered care and counseling.
Predictors of isoniazid preventive therapy completion among adults newly diagnosed with HIV in rural Malawi. (2018). Little KM., Khundi M., Barnes GL., Ngwira LG., Nkhoma A., Makombe S., Corbett EL., Chaisson RE., Dowdy DW, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease, 22, 371-377
SETTING: To reduce the risk of tuberculosis (TB) among individuals with human immunodeficiency virus (HIV) infection, the World Health Organization recommends at least 6 months of isoniazid preventive therapy (IPT). Completion of IPT remains a major challenge in resource-limited settings. OBJECTIVE: To evaluate predictors of IPT completion in individuals newly diagnosed with HIV. DESIGN: Predictors of IPT completion among adults newly diagnosed with HIV in rural Malawi were evaluated using a multilevel logistic regression model. RESULTS: Of 974 participants who screened negative for active TB and were started on IPT, 732 (75%) completed treatment. Only one IPT-eligible individual refused treatment. Participants who were aged <25 years (compared with those aged 45 years, adjusted OR [aOR] 0.33, 95%CI 0.18-0.60) and male (compared to non-pregnant females, aOR 0.57, 95%CI 0.37-0.88) had lower odds of IPT completion. CONCLUSION: IPT provision at the time of initial HIV diagnosis was highly acceptable in rural Malawi; three quarters of those who initiated IPT successfully completed therapy. We observed lower odds of completion among males and among female participants aged <25 years. Additional efforts may be needed to ensure IPT completion among males and young females who have recently been diagnosed with HIV.
Of Testing and Treatment: Implications of Implementing New Regimens for Multidrug-Resistant Tuberculosis. (2018). Dowdy DW., Theron G., Tornheim JA., Warren R., Kendall EA, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 65, 1206-1211
A novel, shorter-course regimen for treating multidrug-resistant (MDR) tuberculosis was recently recommended by the World Health Organization. However, the most appropriate use of drug susceptibility testing (DST) to support this regimen is less clear. Implementing countries must therefore often choose between using a standardized regimen despite high levels of underlying drug resistance or require more stringent DST prior to treatment initiation. The former carries a high likelihood of exposing patients to de facto monotherapy with a critical drug class (fluoroquinolones), whereas the latter could exclude large groups of patients from their most effective treatment option. We discuss the implications of this dilemma and argue for an approach that will integrate DST into the delivery of any novel antimicrobial regimen, without excessively stringent requirements. Such guidance could make the novel MDR tuberculosis regimen available to most patients while reducing the risk of generating additional drug resistance.
Tuberculosis Mortality in the United States: Epidemiology and Prevention Opportunities. (2018). Beavers SF., Pascopella L., Davidow AL., Mangan JM., Hirsch-Moverman YR., Golub JE., Blumberg HM., Webb RM., Royce RA., Buskin SE., Leonard MK., Weinfurter PC., Belknap RW., Hughes SE., Warkentin JV., Welbel SF., Miller TL., Kundipati SR., Lauzardo M., Barry PM., Katz DJ., Garrett DO., Graviss EA., Flood JM, Annals of the American Thoracic Society, 15, 683-692
Rationale: More information on risk factors for death from tuberculosis in the United States could help reduce the tuberculosis mortality rate, which has remained steady for more than a decade.Objective: To identify risk factors for tuberculosis-related death in adults.Methods: We performed a retrospective study of 1,304 adults with tuberculosis who died before treatment completion and 1,039 frequency-matched control subjects who completed tuberculosis treatment in 2005 to 2006 in 13 states reporting 65% of U.S. tuberculosis cases. We used in-depth record abstractions and a standard algorithm to classify deaths in persons with tuberculosis as tuberculosis-related or not. We then compared these classifications to causes of death as coded in death certificates. We used multivariable logistic regression to calculate adjusted odds ratios for predictors of tuberculosis-related death among adults compared with those who completed tuberculosis treatment.Results: Of 1,304 adult deaths, 942 (72%) were tuberculosis related, 272 (21%) were not, and 90 (7%) could not be classified. Of 847 tuberculosis-related deaths with death certificates available, 378 (45%) did not list tuberculosis as a cause of death. Adjusting for known risks, we identified new risks for tuberculosis-related death during treatment: absence of pyrazinamide in the initial regimen (adjusted odds ratio, 3.4; 95% confidence interval, 1.9-6.0); immunosuppressive medications (adjusted odds ratio, 2.5; 95% confidence interval, 1.1-5.6); incomplete tuberculosis diagnostic evaluation (adjusted odds ratio, 2.2; 95% confidence interval, 1.5-3.3), and an alternative nontuberculosis diagnosis before tuberculosis diagnosis (adjusted odds ratio, 1.6; 95% confidence interval, 1.2-2.2).Conclusions: Most persons who died with tuberculosis had a tuberculosis-related death. Intensive record review revealed tuberculosis as a cause of death more often than did death certificate diagnoses. New tools, such as a tuberculosis mortality risk score based on our study findings, may identify patients with tuberculosis for in-hospital interventions to prevent death.
Delay in seeking care for tuberculosis symptoms among adults newly diagnosed with HIV in rural Malawi. (2018). Ngwira LG., Dowdy DW., Khundi M., Barnes GL., Nkhoma A., Choko AT., Murowa M., Chaisson RE., Corbett EL., Fielding K, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease, 22, 280-286
SETTING: Ten primary health clinics in rural Thyolo District, Malawi. OBJECTIVE: Tuberculosis (TB) is a common initial presentation of human immunodeficiency virus (HIV) infection. We investigated the time from TB symptom onset to HIV diagnosis to describe TB health-seeking behaviour in adults newly diagnosed with HIV. DESIGN: We asked adults (18 years) about the presence and duration of TB symptoms at the time of receiving a new HIV diagnosis. Associations with delayed health seeking (defined as >30 and >90 days from the onset of TB symptoms) were evaluated using multivariable logistic regression. RESULTS: TB symptoms were reported by 416 of 1265 participants (33%), of whom 36% (150/416) had been symptomatic for >30 days before HIV testing. Most participants (260/416, 63%) were below the poverty line (US$0.41 per household member per day). Patients who first sought care from informal providers had an increased odds of delay of >30 days (adjusted odds ratio [aOR] 1.6, 95%CI 0.9-2.8) or 90 days (aOR 2.0, 95%CI 1.1-3.8). CONCLUSIONS: Delayed health seeking for TB-related symptoms was common. Poverty was ubiquitous, but had no clear relationship to diagnostic delay. HIV-positive individuals who first sought care from informal providers were more likely to experience diagnostic delays for TB symptoms.
What Will It Take to Reduce HIV Incidence in the United States: A Mathematical Modeling Analysis. (2018). Perry A., Kasaie P., Dowdy DW., Shah M, Open forum infectious diseases, 5, ofy008
BACKGROUND: The National HIV/AIDS Strategy has set ambitious goals to improve the epidemic in the United States. However, there is a paucity of usable program-level benchmarks tied to population-level epidemiologic goals. Our objective was to define tangible benchmarks for annual rates along the care continuum that are likely to translate to meaningful reductions in incidence. METHODS: We used a validated mathematical model of HIV transmission and care engagement to characterize care continuum parameters that would translate into 50% reductions in incidence by 2025, compared with a base case scenario of the current US care continuum. We generated a large pool of simulations in which rates of screening, linkage, and retention in care were varied across wide ranges to evaluate permutations that halved incidence by 2025. RESULTS: Among all simulations, 7% achieved a halving of incidence. It was impossible for our simulations to achieve this target if the annual rate of disengagement from care exceeded 20% per year, even at high rates of care reengagement. When retention in care was 95% per year and people living with HIV (PLWH) out of care reengaged within 1.5 years (on average), the probability of halving incidence by 2025 was approximately 90%. CONCLUSIONS: HIV programs should aim to retain at least 95% of PLWH in care annually and reengage people living with HIV into care within an average of 1.5 years to achieve the goal of halving HIV incidence by 2025.
Risk factors associated with cluster size of Mycobacterium tuberculosis (Mtb) of different RFLP lineages in Brazil. (2018). Peres RL., Vinhas SA., Ribeiro FKC., Palaci M., do Prado TN., Reis-Santos B., Zandonade E., Suffys PN., Golub JE., Riley LW., Maciel EL, BMC infectious diseases, 18, 71
BACKGROUND: Tuberculosis (TB) transmission is influenced by patient-related risk, environment and bacteriological factors. We determined the risk factors associated with cluster size of IS6110 RFLP based genotypes of Mycobacterium tuberculosis (Mtb) isolates from Vitoria, Espirito Santo, Brazil. METHODS: Cross-sectional study of new TB cases identified in the metropolitan area of Vitoria, Brazil between 2000 and 2010. Mtb isolates were genotyped by the IS6110 RFLP, spoligotyping and RD(Rio). The isolates were classified according to genotype cluster sizes by three genotyping methods and associated patient epidemiologic characteristics. Regression Model was performed to identify factors associated with cluster size. RESULTS: Among 959 Mtb isolates, 461 (48%) cases had an isolate that belonged to an RFLP cluster, and six clusters with ten or more isolates were identified. Of the isolates spoligotyped, 448 (52%) were classified as LAM and 412 (48%) as non-LAM. Our regression model found that 6-9 isolates/RFLP cluster were more likely belong to the LAM family, having the RD(Rio) genotype and to be smear-positive (adjusted OR = 1.17, 95% CI 1.08-1.26; adjusted OR = 1.25, 95% CI 1.14-1.37; crude OR = 2.68, 95% IC 1.13-6.34; respectively) and living in a Serra city neighborhood decrease the risk of being in the 6-9 isolates/RFLP cluster (adjusted OR = 0.29, 95% CI, 0.10-0.84), than in the others groups. Individuals aged 21 to 30, 31 to 40 and > 50 years were less likely of belonging the 2-5 isolates/RFLP cluster than unique patterns compared to individuals < 20 years of age (adjusted OR = 0.49, 95% CI 0.28-0.85, OR = 0.43 95% CI 0.24-0.77and OR = 0. 49, 95% CI 0.26-0.91), respectively. The extrapulmonary disease was less likely to occur in those infected with strains in the 2-5 isolates/cluster group (adjustment OR = 0.45, 95% CI 0.24-0.85) than unique patterns. CONCLUSIONS: We found that a large proportion of new TB infections in Vitoria is caused by prevalent Mtb genotypes belonging to the LAM family and RD(Rio) genotypes. Such information demonstrates that some genotypes are more likely to cause recent transmission. Targeting interventions such as screening in specific areas and social risk groups, should be a priority for reducing transmission.
Gender-based violence screening methods preferred by women visiting a public hospital in Pune, India. (2018). Suryavanshi N., Naik S., Waghmare S., Gupte N., Khan S., Mave V., Deluca A., Gupta A., Golub J., Bollinger RC., Shankar A, BMC women's health, 18, 19
BACKGROUND: Gender-based violence (GBV) is a major global public health concern and is a risk factor for adverse health outcomes. Early identification of GBV is crucial for improved health outcomes. Interactions with health care providers may provide a unique opportunity for routine GBV screening, if a safe, confidential environment can be established. METHODS: Between November 2014 and February 2015, a cross-sectional, observational study was conducted where women were interviewed about their opinions concerning GBV screening in a tertiary health care setting in Pune, India. Trained counsellors interviewed 300 women at different out-patient and in-patient departments using a semi-structured questionnaire. RESULTS: Twenty-three percent of these women reported experiencing GBV in their life. However, 90% of women said they had never been asked about GBV in a health care setting. Seventy-two percent expressed willingness to be asked about GBV by their health care providers, with the preferred provider being nurses or counsellors. More than half (53%) women reported face-to-face interview as the most preferred method for screening. There were no major differences in these preferences by GBV history status. CONCLUSIONS: Our study provides evidence for preferred GBV screening methods and optimal provider engagement as perceived by women attending a public hospital.
Metformin Use Reverses the Increased Mortality Associated With Diabetes Mellitus During Tuberculosis Treatment. (2018). Degner NR., Wang JY., Golub JE., Karakousis PC, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 66, 198-205
BACKGROUND: The global type 2 diabetes mellitus (DM) epidemic threatens progress made in reducing tuberculosis (TB)-related mortality worldwide. Previous clinical studies have not fully evaluated potential confounding variables in addressing the impact of DM on TB treatment outcomes. The antidiabetic agent metformin regulates autophagy and may play a role as a host-directed therapeutic adjuvant to antitubercular treatment. METHODS: We conducted a retrospective cohort study comprising patients aged ≥13 years undergoing treatment for culture-confirmed, drug-susceptible pulmonary TB. We assessed the effect of DM on mortality during TB treatment and 2-month TB sputum-culture conversion. We also evaluated the effect of metformin use on survival during TB treatment. RESULTS: Among 2416 patients undergoing TB treatment, after adjusting for age, sex, chronic kidney disease, cancer, hepatitis C, tobacco use, cavitary disease, and treatment adherence, patients with DM had 1.91 times higher odds (95% confidence interval [CI], 1.51-2.40) of death during TB treatment than patients without DM, and 1.72 (95% CI, 1.25-2.38) times higher odds of remaining culture-positive at 2 months. Metformin use in patients with DM was significantly associated with decreased mortality during TB treatment (hazard ratio, 0.56 [95% CI, .39-.82]), and metformin users had similar mortality as patients without DM. CONCLUSIONS: This study suggests that despite multiple potential confounding variables, DM poses an increased risk of adverse TB treatment outcomes. There was a significant association between metformin use and decreased mortality during TB treatment, suggesting a potential role for this agent as adjunctive, host-directed therapy.
Brief Report: "Give Me Some Time": Facilitators of and Barriers to Uptake of Home-Based HIV Testing During Household Contact Investigation for Tuberculosis in Kampala, Uganda. (2018). Armstrong-Hough M., Ggita J., Ayakaka I., Dowdy D., Cattamanchi A., Haberer JE., Katamba A., Davis JL, Journal of acquired immune deficiency syndromes (1999), 77, 400-404
BACKGROUND: Integrating home-based HIV counseling and testing (HCT) with tuberculosis (TB) evaluation could improve the uptake of HIV testing among household contacts of patients with active TB. We sought to identify the facilitators of and barriers to HCT during household contact investigation for TB in Kampala, Uganda. METHODS: We nested semi-structured interviews with 28 household contacts who were offered home-based HCT in a household-randomized trial of home-based strategies for TB contact investigation. Respondents reflected on their experiences of the home visit, the social context of the household, and their decision to accept or decline HIV testing. We used content analysis to identify and evaluate facilitators of and barriers to testing, then categorized the emergent themes using the Capability, Opportunity, Motivation, and Behavior (COM-B) model. RESULTS: Facilitators included a preexisting desire to confirm HIV status or to show support for the index TB patient; a perception that home-based services are convenient; and positive perceptions of lay health workers. Key barriers included fear of results and feeling psychologically unprepared to receive results. The social influence of other household members operated as both a facilitator and a barrier. CONCLUSIONS: Preexisting motivation, psychological readiness to test, and the social context of the household are major contributors to the decision to test for HIV at home. Uptake might be improved by providing normalizing information about HCT before the visit, by offering a second HCT opportunity, by offering self-tests with follow-up counseling, or by introducing HCT using "opt-out" language.
Prevalence of dysglycemia and clinical presentation of pulmonary tuberculosis in Western India. (2018). Mave V., Meshram S., Lokhande R., Kadam D., Dharmshale S., Bharadwaj R., Kagal A., Pradhan N., Deshmukh S., Atre S., Sahasrabudhe T., Barthwal M., Meshram S., Kakrani A., Kulkarni V., Raskar S., Suryavanshi N., Shivakoti R., Chon S., Selvin E., Gupte A., Gupta A., Gupte N., Golub JE, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease, 21, 1280-1287
SETTING: Pune, India. OBJECTIVES: To estimate the prevalence and risk factors of pre-diabetes mellitus (DM) and DM, and its associations with the clinical presentation of tuberculosis (TB). DESIGN: Screening for DM was conducted among adults (age 18 years) with confirmed TB between December 2013 and January 2017. We used multinomial regression to evaluate the risk factors for pre-DM (glycated hemoglobin [HbA1c] 5.7-6.5% or fasting glucose 100-125 mg/dl) and DM (HbA1c 6.5% or fasting glucose 126 mg/dl or random blood glucose > 200 mg/dl or self-reported DM history/treatment) and the association of dysglycemia with the severity of TB disease. RESULTS: Among 1793 participants screened, 890 (50%) had microbiologically confirmed TB. Of these, 33% had pre-DM and 18% had DM; 41% were newly diagnosed. The median HbA1c level among newly diagnosed DM was 7.0% vs. 10.3% among known DM (P < 0.001). DM (adjusted OR [aOR] 4.94, 95%CI 2.33-10.48) and each per cent increase in HbA1c (aOR 1.42, 95%CI 1.01-2.01) was associated with >1+ smear grade or 9 days to TB detection. CONCLUSION: Over half of newly diagnosed TB patients had DM or pre-DM. DM and increasing dysglycemia was associated with higher bacterial burden at TB diagnosis, potentially indicating a higher risk of TB transmission to close contacts.
Secondhand Smoke Exposure and Validity of Self-Report in Low-Income Women and Children in India. (2018). Elf JL., Kinikar A., Khadse S., Mave V., Gupte N., Kulkarni V., Patekar S., Raichur P., Cohen J., Breysse PN., Gupta A., Golub JE, Pediatrics, 141, S118-S129
BACKGROUND: There is limited validation of self-reported measures for secondhand smoke (SHS) exposure in low- and middle-income countries. We evaluated the validity of standard self-reported measures among women and children in urban India. METHODS: Structured questionnaires were administered, and household air and hair samples were analyzed for nicotine concentration. RESULTS: In total, 141 households of 70 child and 71 adult participants were included. Air nicotine was detected in 72 (51%) homes, and 35 (75%) child and 12 (56%) adult participants had detectable hair nicotine. Correlation between air and hair nicotine was significant in children (r = 0.5; P = .0002) but not in adults (r = -0.1; P = .57). Poor correlation was found between self-reported measures of exposure and both air and hair nicotine. No questions were significantly correlated with hair nicotine, and the highest-magnitude correlation with air nicotine was for how often someone smoked inside for adults (r = 0.4; P = .10) and for home preparation of mishri (a smokeless tobacco product prepared for consumption by roasting) for children (r = 0.4; P = .39). The highest value for sensitivity by using air nicotine as the gold standard was for whether people smelled other families preparing mishri (47%; 95% confidence interval: 31-62) and prepared mishri in their own homes (50%; 95% confidence interval: 19-81). CONCLUSIONS: These results raise caution in using or evaluating self-reported SHS exposure in these communities. More appropriate questions for this population are needed, including mishri preparation as a source of SHS exposure.
Integrating social justice concerns into economic evaluation for healthcare and public health: A systematic review. (2017). Dukhanin V., Searle A., Zwerling A., Dowdy DW., Taylor HA., Merritt MW, Social science & medicine (1982), 198, 27-35
Social justice is the moral imperative to avoid and remediate unfair distributions of societal disadvantage. In priority setting in healthcare and public health, social justice reaches beyond fairness in the distribution of health outcomes and economic impacts to encompass fairness in the distribution of policy impacts upon other dimensions of well-being. There is an emerging awareness of the need for economic evaluation to integrate all such concerns. We performed a systematic review (1) to describe methodological solutions suitable for integrating social justice concerns into economic evaluation, and (2) to describe the challenges that those solutions face. To be included, publications must have captured fairness considerations that (a) involve cross-dimensional subjective personal life experience and (b) can be manifested at the level of subpopulations. We identified relevant publications using an electronic search in EMBASE, PubMed, EconLit, PsycInfo, Philosopher's Index, and Scopus, including publications available in English in the past 20 years. Two reviewers independently appraised candidate publications, extracted data, and synthesized findings in narrative form. Out of 2388 publications reviewed, 26 were included. Solutions sought either to incorporate relevant fairness considerations directly into economic evaluation or to report them alongside cost-effectiveness measures. The majority of reviewed solutions, if adapted to integrate social justice concerns, would require their explicit quantification. Four broad challenges related to the implementation of these solutions were identified: clarifying the normative basis; measuring and determining the relative importance of criteria representing that basis; combining the criteria; and evaluating trade-offs. All included solutions must grapple with an inherent tension: they must either face the normative and operational challenges of quantifying social justice concerns or accede to offering incomplete policy guidance. Interdisciplinary research and broader collaborations are crucial to address these challenges and to support due attention to social justice in priority setting.
Impact of Targeted Tuberculosis Vaccination Among a Mining Population in South Africa: A Model-Based Study. (2017). Shrestha S., Chihota V., White RG., Grant AD., Churchyard GJ., Dowdy DW, American journal of epidemiology, 186, 1362-1369
Optimizing the use of new tools, such as vaccines, may play a crucial role in reaching global targets for tuberculosis (TB) control. Some of the most promising candidate vaccines target adults, although high-coverage mass vaccinations may be logistically more challenging among this population than among children. Vaccine-delivery strategies that target high-risk groups or settings might yield proportionally greater impact than do those that target the general population. We developed an individual-based TB transmission model representing a hypothetical population consisting of people who worked in South African gold mines or lived in associated labor-sending communities. We simulated the implementation of a postinfection adult vaccine with 60% efficacy and a mean effect duration of 10 years. We then compared the impact of a mine-targeted vaccination strategy, in which miners were vaccinated while in the mines, with that of a community-targeted strategy, in which random individuals within the labor-sending communities were vaccinated. Mine-targeted vaccination averted an estimated 0.37 TB cases per vaccine dose compared with 0.25 for community-targeted vaccination, for a relative efficacy of 1.46 (95% range, 1.13-1.91). The added benefit of mine-targeted vaccination primarily reflected the disproportionate demographic burden of TB among the population of adult males as a whole. As novel vaccines for TB are developed, venue-based vaccine delivery that targets high-risk demographic groups may improve both vaccine feasibility and the impact on transmission.
Multidrug-resistant tuberculosis in India: looking back, thinking ahead. (2017). Fojo AT., Dowdy DW, The Lancet. Public health, 2, e8-e9
Estimated clinical impact of the Xpert MTB/RIF Ultra cartridge for diagnosis of pulmonary tuberculosis: A modeling study. (2017). Kendall EA., Schumacher SG., Denkinger CM., Dowdy DW, PLoS medicine, 14, e1002472
BACKGROUND: The Xpert MTB/RIF (Xpert) assay offers rapid and accurate diagnosis of tuberculosis (TB) but still suffers from imperfect sensitivity. The newer Xpert MTB/RIF Ultra cartridge has shown improved sensitivity in recent field trials, but at the expense of reduced specificity. The clinical implications of switching from the existing Xpert cartridge to the Xpert Ultra cartridge in different populations remain uncertain. METHODS AND FINDINGS: We developed a Markov microsimulation model of hypothetical cohorts of 100,000 individuals undergoing diagnostic sputum evaluation with Xpert for suspected pulmonary TB, in each of 3 emblematic settings: an HIV clinic in South Africa, a public TB center in India, and an adult primary care setting in China. In each setting, we used existing data to project likely diagnostic results, treatment decisions, and ultimate clinical outcomes, assuming use of the standard Xpert versus Xpert Ultra cartridge. Our primary outcomes were the projected number of additional unnecessary treatments generated, the projected number of TB deaths averted, and the projected number of unnecessary treatments generated per TB death averted, if standard Xpert were switched to Xpert Ultra. We also simulated alternative approaches to interpreting positive results of the Ultra cartridge's semi-quantitative trace call. Extensive sensitivity and uncertainty analyses were performed to evaluate the drivers and generalizability of projected results. In the Indian TB center setting, replacing the standard Xpert cartridge with the Xpert Ultra cartridge was projected to avert 0.5 TB deaths (95% uncertainty range [UR]: 0, 1.3) and generate 18 unnecessary treatments (95% UR: 10, 29) per 1,000 individuals evaluated-resulting in a median ratio of 38 incremental unnecessary treatments added by Ultra per incremental death averted by Ultra compared to outcomes using standard Xpert (95% UR: 12, indefinite upper bound). In the South African HIV care setting-where TB mortality rates are higher and Ultra's improved sensitivity has greater absolute benefit-this ratio improved to 7 unnecessary treatments per TB death averted (95% UR: 2, 43). By contrast, in the Chinese primary care setting, this ratio was much less favorable, at 372 unnecessary treatments per TB death averted (95% UR: 75, indefinite upper bound), although the projected number of unnecessary treatments using Xpert Ultra was lower (with a possibility of no increased overtreatment) when using specificity data only from lower-burden settings. Alternative interpretations of the trace call had little effect on these ratios. Limitations include uncertainty in key parameters (including the clinical implications of false-negative results), the exclusion of transmission effects, and restriction of this analysis to adult pulmonary TB. CONCLUSIONS: Switching from the standard Xpert cartridge to the Xpert Ultra cartridge for diagnosis of adult pulmonary TB may have different consequences in different clinical settings. In settings with high TB and HIV prevalence, Xpert Ultra is likely to offer considerable mortality benefit, whereas in lower-prevalence settings, Xpert Ultra will likely result in considerable overtreatment unless the possibility of higher specificity of Ultra in lower-prevalence settings in confirmed. The ideal use of the Ultra cartridge may therefore involve a more nuanced, setting-specific approach to implementation, with priority given to populations in which the anticipated prevalence of TB (and HIV) is the highest.
Mathematical Modeling of "Chronic" Infectious Diseases: Unpacking the Black Box. (2017). Fojo AT., Kendall EA., Kasaie P., Shrestha S., Louis TA., Dowdy DW, Open forum infectious diseases, 4, ofx172
BACKGROUND: Mathematical models are increasingly used to understand the dynamics of infectious diseases, including "chronic" infections with long generation times. Such models include features that are obscure to most clinicians and decision-makers. METHODS: Using a model of a hypothetical active case-finding intervention for tuberculosis in India as an example, we illustrate the effects on model results of different choices for model structure, input parameters, and calibration process. RESULTS: Using the same underlying data, different transmission models produced different estimates of the projected intervention impact on tuberculosis incidence by 2030 with different corresponding uncertainty ranges. We illustrate the reasons for these differences and present a simple guide for clinicians and decision-makers to evaluate models of infectious diseases. CONCLUSIONS: Mathematical models of chronic infectious diseases must be understood to properly inform policy decisions. Improved communication between modelers and consumers is critical if model results are to improve the health of populations.
Indoor air pollution from secondhand tobacco smoke, solid fuels, and kerosene in homes with active tuberculosis disease in South Africa. (2017). Elf JL., Eke O., Rakgokong M., Variava E., Baliram Y., Motlhaoleng K., Lebina L., Shapiro AE., Breysse PN., Golub JE., Martinson N, BMC research notes, 10, 591
OBJECTIVES: Secondhand tobacco smoke (SHS), use of solid fuels, and kerosene may play an important role in perpetuating the tuberculosis (TB) epidemic. The purpose of this study was to explore the prevalence of household air pollution (HAP) from these sources in homes of someone with TB in a high HIV-prevalence setting. A convenience sample of homes and household members participating in an ongoing active case-finding study in Matlosana district townships surrounding Klerksdorp, South Africa were included. RESULTS: We found a high prevalence of air pollution from SHS, solid fuels, and kerosene among individuals in homes with a case of prevalent active TB disease in Klerksdorp, South Africa. Adults in 40% of homes reported a daily smoker in the home, and 70% of homes had detectable air nicotine. In homes with a history of previous TB (prior to but not including the index case) as compared to those without previous TB, both SHS (83% vs. 65%, respectively) and solid/kerosene fuel use for more than 1 h/day (27% vs. 21%, respectively) were more prevalent. Larger studies are needed to estimate the risk of TB from these types of air pollution in HIV infected individuals and settings with high HIV prevalence.
Is it time for Brazil to prioritize TB preventive therapy for all people living with HIV? (2017). Maciel EL., Prado TND., Andrade KB., Golub JE, The Brazilian journal of infectious diseases : an official publication of the Brazilian Society of Infectious Diseases, 22, 74-75
What We Know About Tuberculosis Transmission: An Overview. (2017). Churchyard G., Kim P., Shah NS., Rustomjee R., Gandhi N., Mathema B., Dowdy D., Kasmar A., Cardenas V, The Journal of infectious diseases, 216, S629-S635
Tuberculosis remains a global health problem with an enormous burden of disease, estimated at 10.4 million new cases in 2015. To stop the tuberculosis epidemic, it is critical that we interrupt tuberculosis transmission. Further, the interventions required to interrupt tuberculosis transmission must be targeted to high-risk groups and settings. A simple cascade for tuberculosis transmission has been proposed in which (1) a source case of tuberculosis (2) generates infectious particles (3) that survive in the air and (4) are inhaled by a susceptible individual (5) who may become infected and (6) then has the potential to develop tuberculosis. Interventions that target these events will interrupt tuberculosis transmission and accelerate the decline in tuberculosis incidence and mortality. The purpose of this article is to provide a high-level overview of what is known about tuberculosis transmission, using the tuberculosis transmission cascade as a framework, and to set the scene for the articles in this series, which address specific aspects of tuberculosis transmission.