Systematic case finding for tuberculosis in HIV-infected people who inject drugs: experience from Pakistan

Alarming Tuberculosis Rate Among People Who Inject Drugs in Vietnam

BACKGROUND

The tuberculosis (TB) epidemic is not homogeneous in the general population but presents high-risk groups. People who inject drugs (PWID) are such a group. However, TB among PWID remains largely undocumented. Our goal was to assess the prevalence of TB and the risk factors associated with TB among PWID in Vietnam.

METHODS

We implemented a cross-sectional survey among 2 community-based cohorts of human immunodeficiency virus (HIV)-positive and HIV-negative PWID in Hai Phong. Participants were screened for TB using questions on TB symptoms. Those who reported any symptom were accompanied by peers to the TB clinic for chest x-ray. If the latter was abnormal, a sputum was collected to perform an Xpert MTB/RIF test.

RESULTS

A total of 885 PWID were screened for TB. For both cohorts, most PWID were male (>90.0%), with a median age of 42 years. Beside heroin injection, 52.5% of participants reported smoking methamphetamine, and 63.2% were on methadone. Among HIV-positive PWID (N = 451), 90.4% were on antiretroviral therapy and 81.6% had a viral load <1000 copies/mL. Using a complete-case analysis, the estimated TB prevalence was 2.3% (95% confidence interval [CI], 1.0-4.5) and 2.1% (95% CI, 0.8-4.2) among HIV-positive and HIV-negative people, respectively. Living as a couple, arrest over the past 6 months, homelessness, and smoking methamphetamine were independently associated with TB but not HIV infection.

CONCLUSIONS

In the context of very large antiretroviral therapy coverage, this extremely high rate of TB among PWID requires urgent actions.

Xpert MTB/RIF and Xpert Ultra assays for screening for pulmonary tuberculosis and rifampicin resistance in adults, irrespective of signs or symptoms

BACKGROUND

Tuberculosis is a leading cause of infectious disease-related death and is one of the top 10 causes of death worldwide. The World Health Organization (WHO) recommends the use of specific rapid molecular tests, including Xpert MTB/RIF or Xpert Ultra, as initial diagnostic tests for the detection of tuberculosis and rifampicin resistance in people with signs and symptoms of tuberculosis. However, the WHO estimates that nearly one-third of all active tuberculosis cases go undiagnosed and unreported. We were interested in whether a single test, Xpert MTB/RIF or Xpert Ultra, could be useful as a screening test to close this diagnostic gap and improve tuberculosis case detection.

OBJECTIVES

To estimate the accuracy of Xpert MTB/RIF and Xpert Ultra for screening for pulmonary tuberculosis in adults, irrespective of signs or symptoms of pulmonary tuberculosis in high-risk groups and in the general population. Screening "irrespective of signs or symptoms" refers to screening of people who have not been assessed for the presence of tuberculosis symptoms (e.g. cough). To estimate the accuracy of Xpert MTB/RIF and Xpert Ultra for detecting rifampicin resistance in adults screened for tuberculosis, irrespective of signs and symptoms of pulmonary tuberculosis in high-risk groups and in the general population.

SEARCH METHODS

We searched 12 databases including the Cochrane Infectious Diseases Group Specialized Register, MEDLINE and Embase, on 19 March 2020 without language restrictions. We also reviewed reference lists of included articles and related Cochrane Reviews, and contacted researchers in the field to identify additional studies.

SELECTION CRITERIA

Cross-sectional and cohort studies in which adults (15 years and older) in high-risk groups (e.g. people living with HIV, household contacts of people with tuberculosis) or in the general population were screened for pulmonary tuberculosis using Xpert MTB/RIF or Xpert Ultra. For tuberculosis detection, the reference standard was culture. For rifampicin resistance detection, the reference standards were culture-based drug susceptibility testing and line probe assays.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data using a standardized form and assessed risk of bias and applicability using QUADAS-2. We used a bivariate random-effects model to estimate pooled sensitivity and specificity with 95% credible intervals (CrIs) separately for tuberculosis detection and rifampicin resistance detection. We estimated all models using a Bayesian approach. For tuberculosis detection, we first estimated screening accuracy in distinct high-risk groups, including people living with HIV, household contacts, people residing in prisons, and miners, and then in several high-risk groups combined.

MAIN RESULTS

We included a total of 21 studies: 18 studies (13,114 participants) evaluated Xpert MTB/RIF as a screening test for pulmonary tuberculosis and one study (571 participants) evaluated both Xpert MTB/RIF and Xpert Ultra. Three studies (159 participants) evaluated Xpert MTB/RIF for rifampicin resistance. Fifteen studies (75%) were conducted in high tuberculosis burden and 16 (80%) in high TB/HIV-burden countries. We judged most studies to have low risk of bias in all four QUADAS-2 domains and low concern for applicability. Xpert MTB/RIF and Xpert Ultra as screening tests for pulmonary tuberculosis In people living with HIV (12 studies), Xpert MTB/RIF pooled sensitivity and specificity (95% CrI) were 61.8% (53.6 to 69.9) (602 participants; moderate-certainty evidence) and 98.8% (98.0 to 99.4) (4173 participants; high-certainty evidence). Of 1000 people where 50 have tuberculosis on culture, 40 would be Xpert MTB/RIF-positive; of these, 9 (22%) would not have tuberculosis (false-positives); and 960 would be Xpert MTB/RIF-negative; of these, 19 (2%) would have tuberculosis (false-negatives). In people living with HIV (1 study), Xpert Ultra sensitivity and specificity (95% CI) were 69% (57 to 80) (68 participants; very low-certainty evidence) and 98% (97 to 99) (503 participants; moderate-certainty evidence). Of 1000 people where 50 have tuberculosis on culture, 53 would be Xpert Ultra-positive; of these, 19 (36%) would not have tuberculosis (false-positives); and 947 would be Xpert Ultra-negative; of these, 16 (2%) would have tuberculosis (false-negatives). In non-hospitalized people in high-risk groups (5 studies), Xpert MTB/RIF pooled sensitivity and specificity were 69.4% (47.7 to 86.2) (337 participants, low-certainty evidence) and 98.8% (97.2 to 99.5) (8619 participants, moderate-certainty evidence). Of 1000 people where 10 have tuberculosis on culture, 19 would be Xpert MTB/RIF-positive; of these, 12 (63%) would not have tuberculosis (false-positives); and 981 would be Xpert MTB/RIF-negative; of these, 3 (0%) would have tuberculosis (false-negatives). We did not identify any studies using Xpert MTB/RIF or Xpert Ultra for screening in the general population. Xpert MTB/RIF as a screening test for rifampicin resistance Xpert MTB/RIF sensitivity was 81% and 100% (2 studies, 20 participants; very low-certainty evidence), and specificity was 94% to 100%, (3 studies, 139 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Of the high-risks groups evaluated, Xpert MTB/RIF applied as a screening test was accurate for tuberculosis in high tuberculosis burden settings. Sensitivity and specificity were similar in people living with HIV and non-hospitalized people in high-risk groups. In people living with HIV, Xpert Ultra sensitivity was slightly higher than that of Xpert MTB/RIF and specificity similar. As there was only one study of Xpert Ultra in this analysis, results should be interpreted with caution. There were no studies that evaluated the tests in people with diabetes mellitus and other groups considered at high-risk for tuberculosis, or in the general population.

GeneXpert Technology for the diagnosis of HIV-associated tuberculosis: Is scale-up worth it?

Recent evaluations of the GeneXpert MTB/RIF assay for the simultaneous detection of Mycobacterium tuberculosis and drug resistance in less than 2 h have stimulated tremendous enthusiasm. This is the breakthrough that tuberculosis (TB) control has been waiting for. In this (retrospective review) case study, sputum samples from strongly suspected pulmonary tuberculosis patients were collected and assessed for the GeneXpert MTB/RIF assay for diagnosing TB and drug resistance in comparison with other tests, including Ziehl–Neelsen smear and Löwenstein–Jensen test. Of 3,784 cases, 5.7% (216/3,784) were human immunodeficiency virus (HIV)-positive and TB co-infected patients. In diagnosing HIV-positive and TB co-infected cases, the sensitivity and specificity of GeneXpert were 76.4% and 100%. While in HIV-negative and TB suspected cases, the sensitivity and specificity were 95.6% and 100%. This new test represents a major milestone for global TB diagnosis and care. It also represents new hope for the millions of people who are at the highest risk of TB and drug-resistant disease. GeneXpert is World Health Organization-endorsed technology representing the gold standard for TB testing despite attaining less sensitivity for HIV and TB co-infected patients as compared to HIV-negative patients.

Closing gaps in the tuberculosis care cascade: an action-oriented research agenda

The care cascade-which evaluates outcomes across stages of patient engagement in a health system-is an important framework for assessing quality of tuberculosis (TB) care. In recent years, there has been progress in measuring care cascades in high TB burden countries; however, there are still shortcomings in our knowledge of how to reduce poor patient outcomes. In this paper, we outline a research agenda for understanding why patients fall through the cracks in the care cascade. The pathway for evidence generation will require new systematic reviews, observational cohort studies, intervention development and testing, and continuous quality improvement initiatives embedded within national TB programs. Certain gaps, such as pretreatment loss to follow-up and post-treatment disease recurrence, should be a priority given a relative paucity of high-quality research to understand and address poor outcomes. Research on interventions to reduce death and loss to follow-up during treatment should move beyond a focus on monitoring (or observation) strategies, to address patient needs including psychosocial and nutritional support. While key research questions vary for each gap, some patient populations may experience disparities across multiple stages of care and should be a priority for research, including men, individuals with a prior treatment history, and individuals with drug-resistant TB. Closing gaps in the care cascade will require investments in a bold and innovative action-oriented research agenda.

Demographic, socio-economic and behavior as risk factors of tuberculosis in Malaysia: a systematic review of the literature

Background Tuberculosis (TB) is making a comeback and has remained one of the main causes of mortality among the list of infectious diseases in Malaysia. Objective To evaluate the burden and demographic, socio-economic and behavior as risk factors of TB among communities in Malaysia. Method A comprehensive search of Scopus, Sciencedirect, PubMed, DOAJ, CINAHL Plus, MyJournal, BIREME, BMC Public Health, Medline, CAB, EMBASE (Excerpta Medica dataBASE), and Web of Science (WoS) was undertaken from the articles published from 1st January 2008 to 31st December 2017 using medical subject heading (MeSH) key terms. Results Of 717 papers screened, 31 eligible studies met our inclusion criteria. Gender, age, marriage status, ethnicity, area of living, being in prison and immigrant were evaluated as demographic factors, while educational level, occupation and household income were evaluated as socio-economic factors. For behavioral factors, smoking, drug abuse, alcohol consumption and other lifestyle practices were evaluated. However, not all the studies were statistically significantly associated with these risk factors. Studies on household income were few and too small to permit a conclusion. We also did not find any study that investigated TB infection among sex workers. Conclusion Immigrant in high density settings may increase the progression of disease infection in Malaysia. The risk factors for the development of TB, specifically in a high-risk population, should be targeted through the implementation of specialized interventions. Further research into the role of indoor and outdoor physical environments is required to better understand the association between the physical environment and the social environment with TB infection.