Detection of lipoarabinomannan (LAM) in urine is an independent predictor of mortality risk in patients receiving treatment for HIV-associated tuberculosis in sub-Saharan Africa: a systematic review and meta-analysis

BackgroundSimple immune capture assays that detect mycobacterial lipoarabinomannan (LAM) antigen in urine are promising new tools for the diagnosis of HIV-associated tuberculosis (HIV-TB). In addition, however, recent prospective cohort studies of patients with HIV-TB have demonstrated associations between LAM in the urine and increased mortality risk during TB treatment, indicating an additional utility of urinary LAM as a prognostic marker. We conducted a systematic review and meta-analysis to summarise the evidence concerning the strength of this relationship in adults with HIV-TB in sub-Saharan Africa, thereby quantifying the assay’s prognostic value.MethodsWe searched MEDLINE and Embase databases using comprehensive search terms for ‘HIV’, ‘TB’, ‘LAM’ and ‘sub-Saharan Africa’. Identified studies were reviewed and selected according to predefined criteria.ResultsWe identified 10 studies eligible for inclusion in this systematic review, reporting on a total of 1172 HIV-TB cases. Of these, 512 patients (44%) tested positive for urinary LAM. After a variable duration of follow-up of between 2 and 6months, overall case fatality rates among HIV-TB cases varied between 7% and 53%. Pooled summary estimates generated by random-effects meta-analysis showed a two-fold increased risk of mortality for urinary LAM-positive HIV-TB cases compared to urinary LAM-negative HIV-TB cases (relative risk 2.3, 95% confidence interval 1.6–3.1). Some heterogeneity was explained by study setting and patient population in sub-group analyses. Five studies also reported multivariable analyses of risk factors for mortality, and pooled summary estimates demonstrated over two-fold increased mortality risk (odds ratio 2.5, 95% confidence interval 1.4–4.5) among urinary LAM-positive HIV-TB cases, even after adjustment for other risk factors for mortality, including CD4 cell count.ConclusionsWe have demonstrated that detectable LAM in urine is associated with increased risk of mortality during TB treatment, and that this relationship remains after adjusting for other risk factors for mortality. This may simply be due to a positive test for urinary LAM serving as a marker of higher mycobacterial load and greater disease dissemination and severity. Alternatively, LAM antigen may directly compromise host immune responses through its known immunomodulatory effects. Detectable LAM in the urine is an independent risk factor for mortality among patients receiving treatment for HIV-TB. Further research is warranted to elucidate the underlying mechanisms and to determine whether this vulnerable patient population may benefit from adjunctive interventions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-016-0603-9) contains supplementary material, which is available to authorized users

Rapid urine-based screening for tuberculosis in HIV-positive patients admitted to hospital in Africa (STAMP): a pragmatic, multicentre, parallel-group, double-blind, randomised controlled trial.

BACKGROUND Current diagnostics for HIV-associated tuberculosis are suboptimal, with missed diagnoses contributing to high hospital mortality and approximately 374 000 annual HIV-positive deaths globally. Urine-based assays have a good diagnostic yield; therefore, we aimed to assess whether urine-based screening in HIV-positive inpatients for tuberculosis improved outcomes. METHODS We did a pragmatic, multicentre, double-blind, randomised controlled trial in two hospitals in Malawi and South Africa. We included HIV-positive medical inpatients aged 18 years or more who were not taking tuberculosis treatment. We randomly assigned patients (1:1), using a computer-generated list of random block size stratified by site, to either the standard-of-care or the intervention screening group, irrespective of symptoms or clinical presentation. Attending clinicians made decisions about care; and patients, clinicians, and the study team were masked to the group allocation. In both groups, sputum was tested using the Xpert MTB/RIF assay (Xpert; Cepheid, Sunnyvale, CA, USA). In the standard-of-care group, urine samples were not tested for tuberculosis. In the intervention group, urine was tested with the Alere Determine TB-LAM Ag (TB-LAM; Alere, Waltham, MA, USA), and Xpert assays. The primary outcome was all-cause 56-day mortality. Subgroup analyses for the primary outcome were prespecified based on baseline CD4 count, haemoglobin, clinical suspicion for tuberculosis; and by study site and calendar time. We used an intention-to-treat principle for our analyses. This trial is registered with the ISRCTN registry, number ISRCTN71603869. FINDINGS Between Oct 26, 2015, and Sept 19, 2017, we screened 4788 HIV-positive adults, of which 2600 (54%) were randomly assigned to the study groups (n=1300 for each group). 13 patients were excluded after randomisation from analysis in each group, leaving 2574 in the final intention-to-treat analysis (n=1287 in each group). At admission, 1861 patients were taking antiretroviral therapy and median CD4 count was 227 cells per μL (IQR 79-436). Mortality at 56 days was reported for 272 (21%) of 1287 patients in the standard-of-care group and 235 (18%) of 1287 in the intervention group (adjusted risk reduction [aRD] -2·8%, 95% CI -5·8 to 0·3; p=0·074). In three of the 12 prespecified, but underpowered subgroups, mortality was lower in the intervention group than in the standard-of-care group for CD4 counts less than 100 cells per μL (aRD -7·1%, 95% CI -13·7 to -0·4; p=0.036), severe anaemia (-9·0%, -16·6 to -1·3; p=0·021), and patients with clinically suspected tuberculosis (-5·7%, -10·9 to -0·5; p=0·033); with no difference by site or calendar period. Adverse events were similar in both groups. INTERPRETATION Urine-based tuberculosis screening did not reduce overall mortality in all HIV-positive inpatients, but might benefit some high-risk subgroups. Implementation could contribute towards global targets to reduce tuberculosis mortality. FUNDING Joint Global Health Trials Scheme of the Medical Research Council, the UK Department for International Development, and the Wellcome Trust

Why healthcare workers are sick of TB.

Dr Thato Mosidi never expected to be diagnosed with tuberculosis (TB), despite widely prevalent exposure and very limited infection control measures. The life-threatening diagnosis of primary extensively drug-resistant TB (XDR-TB) came as an even greater shock. The inconvenient truth is that, rather than being protected, Dr Mosidi and thousands of her healthcare colleagues are at an increased risk of TB and especially drug-resistant TB. In this viewpoint paper we debunk the widely held false belief that healthcare workers are somehow immune to TB disease (TB-proof) and explore some of the key factors contributing to the pervasive stigmatization and subsequent non-disclosure of occupational TB. Our front-line workers are some of the first to suffer the consequences of a progressively more resistant and fatal TB epidemic, and urgent interventions are needed to ensure the safety and continued availability of these precious healthcare resources. These include the rapid development and scale-up of improved diagnostic and treatment options, strengthened infection control measures, and focused interventions to tackle stigma and discrimination in all its forms. We call our colleagues to action to protect themselves and those they care for

Tuberculosis in Hospitalized Patients With Human Immunodeficiency Virus: Clinical Characteristics, Mortality, and Implications From the Rapid Urine-based Screening for Tuberculosis to Reduce AIDS Related Mortality in Hospitalized Patients in Africa.

BACKGROUND: Tuberculosis (TB) is the major killer of people living with human immunodeficiency virus (HIV) globally, with suboptimal diagnostics and management contributing to high case-fatality rates. METHODS: A prospective cohort of patients with confirmed TB (Xpert MTB/RIF and/or Determine TB-LAM Ag positive) identified through screening HIV-positive inpatients with sputum and urine diagnostics in Malawi and South Africa (Rapid urine-based Screening for Tuberculosis to reduce AIDS Related Mortality in hospitalized Patients in Africa [STAMP] trial). Urine was tested prospectively (intervention) or retrospectively (standard of care arm). We defined baseline clinical phenotypes using hierarchical cluster analysis, and also used Cox regression analysis to identify associations with early mortality (≤56 days). RESULTS: Of 322 patients with TB confirmed between October 2015 and September 2018, 78.0% had ≥1 positive urine test. Antiretroviral therapy (ART) coverage was 80.2% among those not newly diagnosed, but with median CD4 count 75 cells/µL and high HIV viral loads. Early mortality was 30.7% (99/322), despite near-universal prompt TB treatment. Older age, male sex, ART before admission, poor nutritional status, lower hemoglobin, and positive urine tests (TB-LAM and/or Xpert MTB/RIF) were associated with increased mortality in multivariate analyses. Cluster analysis (on baseline variables) defined 4 patient subgroups with early mortality ranging from 9.8% to 52.5%. Although unadjusted mortality was 9.3% lower in South Africa than Malawi, in adjusted models mortality was similar in both countries (hazard ratio, 0.9; P = .729). CONCLUSIONS: Mortality following prompt inpatient diagnosis of HIV-associated TB remained unacceptably high, even in South Africa. Intensified management strategies are urgently needed, for which prognostic indicators could potentially guide both development and subsequent use

Why healthcare workers are sick of TB

Dr Thato Mosidi never expected to be diagnosed with tuberculosis (TB), despite widely prevalent exposure and very limited infection control measures. The life-threatening diagnosis of primary extensively drug-resistant TB (XDR-TB) came as an even greater shock. The inconvenient truth is that, rather than being protected, Dr Mosidi and thousands of her healthcare colleagues are at an increased risk of TB and especially drug-resistant TB. In this viewpoint paper we debunk the widely held false belief that healthcare workers are somehow immune to TB disease (TB-proof) and explore some of the key factors contributing to the pervasive stigmatization and subsequent non-disclosure of occupational TB. Our front-line workers are some of the first to suffer the consequences of a progressively more resistant and fatal TB epidemic, and urgent interventions are needed to ensure the safety and continued availability of these precious healthcare resources. These include the rapid development and scale-up of improved diagnostic and treatment options, strengthened infection control measures, and focused interventions to tackle stigma and discrimination in all its forms. We call our colleagues to action to protect themselves and those they care for

Agents of change: The role of healthcare workers in the prevention of nosocomial and occupational tuberculosis.

Healthcare workers (HCWs) play a central role in global tuberculosis (TB) elimination efforts but their contributions are undermined by occupational TB. HCWs have higher rates of latent and active TB than the general population due to persistent occupational TB exposure, particularly in settings where there is a high prevalence of undiagnosed TB in healthcare facilities and TB infection control (TB-IC) programmes are absent or poorly implemented. Occupational health programmes in high TB burden settings are often weak or non-existent and thus data that record the extent of the increased risk of occupational TB globally are scarce. HCWs represent a limited resource in high TB burden settings and occupational TB can lead to workforce attrition. Stigma plays a role in delayed diagnosis, poor treatment outcomes and impaired well-being in HCWs who develop TB. Ensuring the prioritization and implementation of TB-IC interventions and occupational health programmes, which include robust monitoring and evaluation, is critical to reduce nosocomial TB transmission to patients and HCWs. The provision of preventive therapy for HCWs with latent TB infection (LTBI) can also prevent progression to active TB. Unlike other patient groups, HCWs are in a unique position to serve as agents of change to raise awareness, advocate for necessary resource allocation and implement TB-IC interventions, with appropriate support from dedicated TB-IC officers at the facility and national TB programme level. Students and community health workers (CHWs) must be engaged and involved in these efforts. Nosocomial TB transmission is an urgent public health problem and adopting rights-based approaches can be helpful. However, these efforts cannot succeed without increased political will, supportive legal frameworks and financial investments to support HCWs in efforts to decrease TB transmission

Cost-effectiveness of urine-based tuberculosis screening in hospitalised patients with HIV in Africa: a microsimulation modelling study.

BACKGROUND: Testing urine improves the number of tuberculosis diagnoses made among patients in hospital with HIV. In conjunction with the two-country randomised Rapid Urine-based Screening for Tuberculosis to Reduce AIDS-related Mortality in Hospitalised Patients in Africa (STAMP) trial, we used a microsimulation model to estimate the effects on clinical outcomes and the cost-effectiveness of adding urine-based tuberculosis screening to sputum screening for hospitalised patients with HIV. METHODS: We compared two tuberculosis screening strategies used irrespective of symptoms among hospitalised patients with HIV in Malawi and South Africa: a GeneXpert assay (Cepheid, Sunnyvale, CA, USA) for Mycobacterium tuberculosis and rifampicin resistance (Xpert) in sputum samples (standard of care) versus sputum Xpert combined with a lateral flow assay for M tuberculosis lipoarabinomannan in urine (Determine TB-LAM Ag test, Abbott, Waltham, MA, USA [formerly Alere]; TB-LAM) and concentrated urine Xpert (intervention). A cohort of simulated patients was modelled using selected characteristics of participants, tuberculosis diagnostic yields, and use of hospital resources in the STAMP trial. We calibrated 2-month model outputs to the STAMP trial results and projected clinical and economic outcomes at 2 years, 5 years, and over a lifetime. We judged the intervention to be cost-effective if the incremental cost-effectiveness ratio (ICER) was less than US$750/year of life saved (YLS) in Malawi and$940/YLS in South Africa. A modified intervention of adding only TB-LAM to the standard of care was also evaluated. We did a budget impact analysis of countrywide implementation of the intervention. FINDINGS: The intervention increased life expectancy by 0·5-1·2 years and was cost-effective, with an ICER of $450/YLS in Malawi and$840/YLS in South Africa. The ICERs decreased over time. At lifetime horizon, the intervention remained cost-effective under nearly all modelled assumptions. The modified intervention was at least as cost-effective as the intervention (ICERs $420/YLS in Malawi and$810/YLS in South Africa). Over 5 years, the intervention would save around 51 000 years of life in Malawi and around 171 000 years of life in South Africa. Health-care expenditure for screened individuals was estimated to increase by $37 million (10·8$261 million (2·8%), respectively. INTERPRETATION: Urine-based tuberculosis screening of all hospitalised patients with HIV could increase life expectancy and be cost-effective in resource-limited settings. Urine TB-LAM is especially attractive because of high incremental diagnostic yield and low additional cost compared with sputum Xpert, making a compelling case for expanding its use to all hospitalised patients with HIV in areas with high HIV burden and endemic tuberculosis. FUNDING: UK Medical Research Council, UK Department for International Development, Wellcome Trust, US National Institutes of Health, Royal College of Physicians, Massachusetts General Hospital

Genetic Determinants of Electrocardiographic P-Wave Duration and Relation to Atrial Fibrillation.

BACKGROUND: The P-wave duration (PWD) is an electrocardiographic measurement that represents cardiac conduction in the atria. Shortened or prolonged PWD is associated with atrial fibrillation (AF). We used exome-chip data to examine the associations between common and rare variants with PWD. METHODS: Fifteen studies comprising 64 440 individuals (56 943 European, 5681 African, 1186 Hispanic, 630 Asian) and ≈230 000 variants were used to examine associations with maximum PWD across the 12-lead ECG. Meta-analyses summarized association results for common variants; gene-based burden and sequence kernel association tests examined low-frequency variant-PWD associations. Additionally, we examined the associations between PWD loci and AF using previous AF genome-wide association studies. RESULTS: We identified 21 common and low-frequency genetic loci (14 novel) associated with maximum PWD, including several AF loci (TTN, CAND2, SCN10A, PITX2, CAV1, SYNPO2L, SOX5, TBX5, MYH6, RPL3L). The top variants at known sarcomere genes (TTN, MYH6) were associated with longer PWD and increased AF risk. However, top variants at other loci (eg, PITX2 and SCN10A) were associated with longer PWD but lower AF risk. CONCLUSIONS: Our results highlight multiple novel genetic loci associated with PWD, and underscore the shared mechanisms of atrial conduction and AF. Prolonged PWD may be an endophenotype for several different genetic mechanisms of AF

Genetic Determinants of Electrocardiographic P-Wave Duration and Relation to Atrial Fibrillation

Background: The P-wave duration (PWD) is an electrocardiographic measurement that represents cardiac conduction in the atria. Shortened or prolonged PWD is associated with atrial fibrillation (AF). We used exome-chip data to examine the associations between common and rare variants with PWD. / Methods: Fifteen studies comprising 64 440 individuals (56 943 European, 5681 African, 1186 Hispanic, 630 Asian) and ≈230 000 variants were used to examine associations with maximum PWD across the 12-lead ECG. Meta-analyses summarized association results for common variants; gene-based burden and sequence kernel association tests examined low-frequency variant-PWD associations. Additionally, we examined the associations between PWD loci and AF using previous AF genome-wide association studies. / Results: We identified 21 common and low-frequency genetic loci (14 novel) associated with maximum PWD, including several AF loci (TTN, CAND2, SCN10A, PITX2, CAV1, SYNPO2L, SOX5, TBX5, MYH6, RPL3L). The top variants at known sarcomere genes (TTN, MYH6) were associated with longer PWD and increased AF risk. However, top variants at other loci (eg, PITX2 and SCN10A) were associated with longer PWD but lower AF risk. / Conclusions: Our results highlight multiple novel genetic loci associated with PWD, and underscore the shared mechanisms of atrial conduction and AF. Prolonged PWD may be an endophenotype for several different genetic mechanisms of AF