Amsterdam Institute of Global Health and Development

Amsterdam, Netherlands

Amsterdam Institute of Global Health and Development

Amsterdam, Netherlands
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Cobelens F.,Amsterdam Institute of Global Health and Development | van Kampen S.,Amsterdam Institute of Global Health and Development | van Kampen S.,KNCV Tuberculosis Foundation | Ochodo E.,Amsterdam Institute of Global Health and Development | And 2 more authors.
PLoS Medicine | Year: 2012

Background: Several interventions for tuberculosis (TB) control have been recommended by the World Health Organization (WHO) over the past decade. These include isoniazid preventive therapy (IPT) for HIV-infected individuals and household contacts of infectious TB patients, diagnostic algorithms for rule-in or rule-out of smear-negative pulmonary TB, and programmatic treatment for multidrug-resistant TB. There is no systematically collected data on the type of evidence that is publicly available to guide the scale-up of these interventions in low- and middle-income countries. We investigated the availability of published evidence on their effectiveness, delivery, and cost-effectiveness that policy makers need for scaling-up these interventions at country level. Methods and Findings: PubMed, Web of Science, EMBASE, and several regional databases were searched for studies published from 1 January 1990 through 31 March 2012 that assessed health outcomes, delivery aspects, or cost-effectiveness for any of these interventions in low- or middle-income countries. Selected studies were evaluated for their objective(s), design, geographical and institutional setting, and generalizability. Studies reporting health outcomes were categorized as primarily addressing efficacy or effectiveness of the intervention. These criteria were used to draw landscapes of published research. We identified 59 studies on IPT in HIV infection, 14 on IPT in household contacts, 44 on rule-in diagnosis, 19 on rule-out diagnosis, and 72 on second-line treatment. Comparative effectiveness studies were relatively few (n = 9) and limited to South America and sub-Saharan Africa for IPT in HIV-infection, absent for IPT in household contacts, and rare for second-line treatment (n = 3). Evaluations of diagnostic and screening algorithms were more frequent (n = 19) but geographically clustered and mainly of non-comparative design. Fifty-four studies evaluated ways of delivering these interventions, and nine addressed their cost-effectiveness. Conclusions: There are substantial gaps in published evidence for scale-up for five WHO-recommended TB interventions settings at country level, which for many countries possibly precludes program-wide implementation of these interventions. There is a strong need for rigorous operational research studies to be carried out in programmatic settings to inform on best use of existing and new interventions in TB control. Please see later in the article for the Editors' Summary. © 2012 Cobelens et al.


Wells W.A.,Global Alliance for TB Drug Development | Boehme C.C.,Foundation for Innovative New Diagnostics | Cobelens F.G.J.,Amsterdam Institute of Global Health and Development | Daniels C.,Treatment Action Group | And 14 more authors.
The Lancet Infectious Diseases | Year: 2013

New tuberculosis drug regimens are creating new priorities for drug susceptibility testing (DST) and surveillance. To minimise turnaround time, rapid DST will need to be prioritised, but developers of these assays will need better data about the molecular mechanisms of resistance. Efforts are underway to link mutations with drug resistance and to develop strain collections to enable assessment of new diagnostic assays. In resource-limited settings, DST might not be appropriate for all patients with tuberculosis. Surveillance data and modelling will help country stakeholders to design appropriate DST algorithms and to decide whether to change drug regimens. Finally, development of practical DST assays is needed so that, in countries where surveillance and modelling show that DST is advisable, these assays can be used to guide clinical decisions for individual patients. If combined judiciously during both development and implementation, new tuberculosis regimens and new DST assays have enormous potential to improve patient outcomes and reduce the burden of disease. © 2013 World Health Organization. Published by Elsevier Ltd/Inc/BV. All rights reserved.


Hoa N.B.,Viet Nam National Tuberculosis Programme | Sy D.N.,Viet Nam National Tuberculosis Programme | Nhung N.V.,Viet Nam National Tuberculosis Programme | Borgdorff M.W.,Amsterdam Institute of Global Health and Development | And 2 more authors.
International Journal of Tuberculosis and Lung Disease | Year: 2012

BACKGROUND: Tuberculosis (TB) prevalence surveys generally rely on a combination of screening methods to identify suspects eligible for sputum culture. OBJECTIVE: To assess the yield of screening methods applied in a recent prevalence survey in Viet Nam and estimate the proportion of TB cases missed due to incomplete participation. METHODS: TB suspects were identified based on self-reported TB history or productive cough by interview and chest X-ray (CXR). We calculated the case yield of these two screening methods by dividing the number of cases detected per method by the total number of cases detected. As not all participants underwent the full screening procedure, we recalculated the maximum yield of the screening methods using multiple imputation methods. RESULTS: The yield from screening by interview and CXR were respectively 38% and 91%. Adjusting for missing data by multiple imputation, we estimated that we missed 9.9% (95%CI 6.8-14.2) of expected TB cases. CONCLUSION: In prevalence surveys, screening by prestructured interview is insufficient, and should be supplemented with CXR to achieve sufficient identification of TB cases. The effect of incomplete participation in the full screening procedure may be substantial and should be adjusted for in the analysis. © 2012 The Union.


Boehme C.C.,Foundation for Innovative New Diagnostics FIND | Nicol M.P.,Groote Schuur Hospital | Nicol M.P.,University of Cape Town | Nabeta P.,Foundation for Innovative New Diagnostics FIND | And 21 more authors.
The Lancet | Year: 2011

The Xpert MTB/RIF test (Cepheid, Sunnyvale, CA, USA) can detect tuberculosis and its multidrug-resistant form with very high sensitivity and specificity in controlled studies, but no performance data exist from district and subdistrict health facilities in tuberculosis-endemic countries. We aimed to assess operational feasibility, accuracy, and effectiveness of implementation in such settings. We assessed adults (≥18 years) with suspected tuberculosis or multidrug-resistant tuberculosis consecutively presenting with cough lasting at least 2 weeks to urban health centres in South Africa, Peru, and India, drug-resistance screening facilities in Azerbaijan and the Philippines, and an emergency room in Uganda. Patients were excluded from the main analyses if their second sputum sample was collected more than 1 week after the first sample, or if no valid reference standard or MTB/RIF test was available. We compared one-off direct MTB/RIF testing in nine microscopy laboratories adjacent to study sites with 2-3 sputum smears and 1-3 cultures, dependent on site, and drug-susceptibility testing. We assessed indicators of robustness including indeterminate rate and between-site performance, and compared time to detection, reporting, and treatment, and patient dropouts for the techniques used. We enrolled 6648 participants between Aug 11, 2009, and June 26, 2010. One-off MTB/RIF testing detected 933 (90·3) of 1033 culture-confirmed cases of tuberculosis, compared with 699 (67·1) of 1041 for microscopy. MTB/RIF test sensitivity was 76·9 in smear-negative, culture-positive patients (296 of 385 samples), and 99·0 specific (2846 of 2876 non-tuberculosis samples). MTB/RIF test sensitivity for rifampicin resistance was 94·4 (236 of 250) and specificity was 98·3 (796 of 810). Unlike microscopy, MTB/RIF test sensitivity was not significantly lower in patients with HIV co-infection. Median time to detection of tuberculosis for the MTB/RIF test was 0 days (IQR 0-1), compared with 1 day (0-1) for microscopy, 30 days (23-43) for solid culture, and 16 days (13-21) for liquid culture. Median time to detection of resistance was 20 days (10-26) for line-probe assay and 106 days (30-124) for conventional drug-susceptibility testing. Use of the MTB/RIF test reduced median time to treatment for smear-negative tuberculosis from 56 days (39-81) to 5 days (2-8). The indeterminate rate of MTB/RIF testing was 2·4 (126 of 5321 samples) compared with 4·6 (441 of 9690) for cultures. The MTB/RIF test can effectively be used in low-resource settings to simplify patients' access to early and accurate diagnosis, thereby potentially decreasing morbidity associated with diagnostic delay, dropout and mistreatment. Foundation for Innovative New Diagnostics, Bill & Melinda Gates Foundation, European and Developing Countries Clinical Trials Partnership (TA2007.40200.009), Wellcome Trust (085251/B/08/Z), and UK Department for International Development. © 2011 Elsevier Ltd.


Cobelens F.G.J.,Amsterdam Institute of Global Health and Development | Kirimunda S.,Makerere University | Lule J.K.,Makerere University | Nuwaha F.,Makerere University
PLoS ONE | Year: 2011

Background: Drug resistance among tuberculosis patients in sub-Saharan Africa is increasing, possibly due to association with HIV infection. We studied drug resistance and HIV infection in a representative sample of 533 smear-positive tuberculosis patients diagnosed in Kampala, Uganda. Methods/Principal Findings: Among 473 new patients, multidrug resistance was found in 5 (1.1%, 95% CI 0.3-2.5) and resistance to any drug in 57 (12.1%, 9.3-15.3). Among 60 previously treated patients this was 7 (11.7%, 4.8-22.6) and 17 (28.3%; 17.5-41.4), respectively. Of 517 patients with HIV results, 165 (31.9%, 27.9-36.1) tested positive. Neither multidrug (adjusted odds ratio (ORadj) 0.7; 95% CI 0.19-2.6) nor any resistance (ORadj 0.7; 0.43-1.3) was associated with HIV status. Primary resistance to any drug was more common among patients who had worked in health care (ORadj 3.5; 1.0-12.0). Conclusion/Significance: Anti-tuberculosis drug resistance rates in Kampala are low and not associated with HIV infection, but may be associated with exposure during health care. © 2011 Lukoye et al.


Mugasa C.M.,Royal Tropical Institute | Mugasa C.M.,Makerere University | Adams E.R.,Royal Tropical Institute | Boer K.R.,Royal Tropical Institute | And 4 more authors.
PLoS Neglected Tropical Diseases | Year: 2012

Background: A range of molecular amplification techniques have been developed for the diagnosis of Human African Trypanosomiasis (HAT); however, careful evaluation of these tests must precede implementation to ensure their high clinical accuracy. Here, we investigated the diagnostic accuracy of molecular amplification tests for HAT, the quality of articles and reasons for variation in accuracy. Methodology: Data from studies assessing diagnostic molecular amplification tests were extracted and pooled to calculate accuracy. Articles were included if they reported sensitivity and specificity or data whereby values could be calculated. Study quality was assessed using QUADAS and selected studies were analysed using the bivariate random effects model. Results: 16 articles evaluating molecular amplification tests fulfilled the inclusion criteria: PCR (n = 12), NASBA (n = 2), LAMP (n = 1) and a study comparing PCR and NASBA (n = 1). Fourteen articles, including 19 different studies were included in the meta-analysis. Summary sensitivity for PCR on blood was 99.0% (95% CI 92.8 to 99.9) and the specificity was 97.7% (95% CI 93.0 to 99.3). Differences in study design and readout method did not significantly change estimates although use of satellite DNA as a target significantly lowers specificity. Sensitivity and specificity of PCR on CSF for staging varied from 87.6% to 100%, and 55.6% to 82.9% respectively. Conclusion: Here, PCR seems to have sufficient accuracy to replace microscopy where facilities allow, although this conclusion is based on multiple reference standards and a patient population that was not always representative. Future studies should, therefore, include patients for which PCR may become the test of choice and consider well designed diagnostic accuracy studies to provide extra evidence on the value of PCR in practice. Another use of PCR for control of disease could be to screen samples collected from rural areas and test in reference laboratories, to spot epidemics quickly and direct resources appropriately. © 2012 Mugasa et al.


Vassall A.,Amsterdam Institute of Global Health and Development | Vassall A.,London School of Hygiene and Tropical Medicine | van Kampen S.,Amsterdam Institute of Global Health and Development | Sohn H.,McGill University | And 14 more authors.
PLoS Medicine | Year: 2011

Background: Xpert MTB/RIF (Xpert) is a promising new rapid diagnostic technology for tuberculosis (TB) that has characteristics that suggest large-scale roll-out. However, because the test is expensive, there are concerns among TB program managers and policy makers regarding its affordability for low- and middle-income settings. Methods and Findings: We estimate the impact of the introduction of Xpert on the costs and cost-effectiveness of TB care using decision analytic modelling, comparing the introduction of Xpert to a base case of smear microscopy and clinical diagnosis in India, South Africa, and Uganda. The introduction of Xpert increases TB case finding in all three settings; from 72%-85% to 95%-99% of the cohort of individuals with suspected TB, compared to the base case. Diagnostic costs (including the costs of testing all individuals with suspected TB) also increase: from US$28-US$49 to US$133-US$146 and US$137-US$151 per TB case detected when Xpert is used "in addition to" and "as a replacement of" smear microscopy, respectively. The incremental cost effectiveness ratios (ICERs) for using Xpert "in addition to" smear microscopy, compared to the base case, range from US$41-$110 per disability adjusted life year (DALY) averted. Likewise the ICERS for using Xpert "as a replacement of" smear microscopy range from US$52-$138 per DALY averted. These ICERs are below the World Health Organization (WHO) willingness to pay threshold. Conclusions: Our results suggest that Xpert is a cost-effective method of TB diagnosis, compared to a base case of smear microscopy and clinical diagnosis of smear-negative TB in low- and middle-income settings where, with its ability to substantially increase case finding, it has important potential for improving TB diagnosis and control. The extent of cost-effectiveness gain to TB programmes from deploying Xpert is primarily dependent on current TB diagnostic practices. Further work is required during scale-up to validate these findings. © 2011 Vassall et al.


Konde-Lule J.,Makerere University | Makumbi F.,Makerere University | Pakker N.,Amsterdam Institute of Global Health and Development | Muyinda A.,Makerere University | And 2 more authors.
AIDS Care - Psychological and Socio-Medical Aspects of AIDS/HIV | Year: 2011

In many resource-poor countries, CD4 count thresholds of eligibility for antiretroviral treatment (ART) were initially low (< 200 cells/mm3) but are now being increased to improve patient survival and to reduce HIV transmission. There are few quantitative data on the effect of such increases on the demand for ART. The objective of this study was to measure HIV prevalence and the proportion of HIV-positives eligible for antiretroviral therapy at different CD4 cut-off levels among users of public health care services in Kampala, Uganda. We recruited 1200 adults from three primary care clinics in Kampala, including equal numbers of family planning (FP) clients, pregnant women, adult patients with any complaint, and persons seeking HIV counseling and testing. All participants were screened for HIV and those positive had a CD4 count done. HIV prevalence in all patients was 16.9% (203/1200). ART eligibility based on CD4 counts significantly increased from 36% at a 200 cells/mm3 cut-off to 44% at 250 cells and to 57% at 350 cells cut-off (p for χ 2 trend < 0.001). We concluded that changing cut-off levels to higher CD4 counts will significantly increase patient load in Kampala's primary care clinics, but a phased implementation should minimize negative effects on quality of care. © 2011 Taylor & Francis.


Pantoja A.,World Health Organization | Fitzpatrick C.,World Health Organization | Vassall A.,Amsterdam Institute of Global Health and Development | Vassall A.,London School of Hygiene and Tropical Medicine | And 2 more authors.
European Respiratory Journal | Year: 2013

Xpert MTB/RIF is a rapid test to diagnose tuberculosis (TB) and rifampicin-resistant TB. Cost and affordability will influence its uptake. We assessed the cost, globally and in 36 high-burden countries, of two strategies for diagnosing TB and multidrug-resistant (MDR)-TB: Xpert with follow-on diagnostics, and conventional diagnostics. Costs were compared with funding available for TB care and control, and donor investments in HIV prevention and care. Using Xpert to diagnose MDR-TB would cost US$70-90 million per year globally and be lower cost than conventional diagnostics globally and in all high-burden countries. Diagnosing TB in HIV-positive people using Xpert would also cost US$90-101 million per year and be lower cost than conventional diagnostics globally and in 33 out of 36 high-burden countries. Testing everyone with TB signs and symptoms would cost US$434-468 million per year globally, much more than conventional diagnostics. However, in European countries, Brazil and South Africa, the cost would represent <10% of TB funding. Introducing Xpert to diagnose MDR-TB and to diagnose TB in HIV-positive people is warranted in many countries. Using it to test everyone with TB signs and symptoms is affordable in several middle-income countries, but financial viability in low-income countries requires large increases in TB funding and/or further price reductions.


Cobelens F.,Amsterdam Institute of Global Health and Development | Van Den Hof S.,Amsterdam Institute of Global Health and Development | Van Den Hof S.,KNCV Tuberculosis Foundation | Pai M.,McGill University | And 3 more authors.
Journal of Infectious Diseases | Year: 2012

Recently, new diagnostic tools for tuberculosis detection and resistance testing have become available. The World Health Organization endorses new tuberculosis diagnostics by using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process. This endorsement process takes place when limited evidence beyond test accuracy is available. There is a need to provide guidance to tuberculosis programs about which new diagnostics to scale up and how best to position them in diagnostic algorithms. To speed adoption of new diagnostics for tuberculosis, the policy recommendation process should be revised to consist of 2 steps: technical recommendation and programmatic recommendation. Technical recommendation would follow the GRADE process and be based on accuracy with limited cost and feasibility data, while programmatic recommendation would include patient-important outcomes, cost-effectiveness when implemented under routine conditions, and factors critical to successful scale-up. The evidence for both steps should be systematically collected, but each requires different study designs. © 2012 The Author.

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