Duncan Chanda

Feasibility, accuracy, and clinical effect of point-of-care Xpert MTB/RIF testing for tuberculosis in primary-care settings in Africa: a multicentre, randomised, controlled trial

BACKGROUND The Xpert MTB/RIF test for tuberculosis is being rolled out in many countries, but evidence is lacking regarding its implementation outside laboratories, ability to inform same-day treatment decisions at the point of care, and clinical effect on tuberculosis-related morbidity. We aimed to assess the feasibility, accuracy, and clinical effect of point-of-care Xpert MTB/RIF testing at primary-care health-care facilities in southern Africa. METHODS In this pragmatic, randomised, parallel-group, multicentre trial, we recruited adults with symptoms suggestive of active tuberculosis from five primary-care health-care facilities in South Africa, Zimbabwe, Zambia, and Tanzania. Eligible patients were randomly assigned using pregenerated tables to nurse-performed Xpert MTB/RIF at the clinic or sputum smear microscopy. Participants with a negative test result were empirically managed according to local WHO-compliant guidelines. Our primary outcome was tuberculosis-related morbidity (measured with the TBscore and Karnofsky performance score [KPS]) in culture-positive patients who had begun anti-tuberculosis treatment, measured at 2 months and 6 months after randomisation, analysed by intention to treat. This trial is registered with Clinicaltrials.gov, number NCT01554384. FINDINGS Between April 12, 2011, and March 30, 2012, we randomly assigned 758 patients to smear microscopy (182 culture positive) and 744 to Xpert MTB/RIF (185 culture positive). Median TBscore in culture-positive patients did not differ between groups at 2 months (2 [IQR 0-3] in the smear microscopy group vs 2 [0·25-3] in the MTB/RIF group; p=0·85) or 6 months (1 [0-3] vs 1 [0-3]; p=0·35), nor did median KPS at 2 months (80 [70-90] vs 90 [80-90]; p=0·23) or 6 months (100 [90-100] vs 100 [90-100]; p=0·85). Point-of-care MTB/RIF had higher sensitivity than microscopy (154 [83%] of 185 vs 91 [50%] of 182; p=0·0001) but similar specificity (517 [95%] 544 vs 540 [96%] of 560; p=0·25), and had similar sensitivity to laboratory-based MTB/RIF (292 [83%] of 351; p=0·99) but higher specificity (952 [92%] of 1037; p=0·0173). 34 (5%) of 744 tests with point-of-care MTB/RIF and 82 (6%) of 1411 with laboratory-based MTB/RIF failed (p=0·22). Compared with the microscopy group, more patients in the MTB/RIF group had a same-day diagnosis (178 [24%] of 744 vs 99 [13%] of 758; p<0·0001) and same-day treatment initiation (168 [23%] of 744 vs 115 [15%] of 758; p=0·0002). Although, by end of the study, more culture-positive patients in the MTB/RIF group were on treatment due to reduced dropout (15 [8%] of 185 in the MTB/RIF group did not receive treatment vs 28 [15%] of 182 in the microscopy group; p=0·0302), the proportions of all patients on treatment in each group by day 56 were similar (320 [43%] of 744 in the MTB/RIF group vs 317 [42%] of 758 in the microscopy group; p=0·6408). INTERPRETATION Xpert MTB/RIF can be accurately administered by a nurse in primary-care clinics, resulting in more patients starting same-day treatment, more culture-positive patients starting therapy, and a shorter time to treatment. However, the benefits did not translate into lower tuberculosis-related morbidity, partly because of high levels of empirical-evidence-based treatment in smear-negative patients. FUNDING European and Developing Countries Clinical Trials Partnership, National Research Foundation, and Claude Leon Foundation.

Tuberculosis treatment and management-an update on treatment regimens, trials, new drugs, and adjunct therapies

WHO estimates that 9 million people developed active tuberculosis in 2013 and 1·5 million people died from it. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis continue to spread worldwide with an estimated 480,000 new cases in 2013. Treatment success rates of MDR and XDR tuberculosis are still low and development of new, more effective tuberculosis drugs and adjunct therapies to improve treatment outcomes are urgently needed. Although standard therapy for drug-sensitive tuberculosis is highly effective, shorter, more effective treatment regimens are needed to reduce the burden of infectious cases. We review the latest WHO guidelines and global recommendations for treatment and management of drug-sensitive and drug-resistant tuberculosis, and provide an update on new drug development, results of several phase 2 and phase 3 tuberculosis treatment trials, and other emerging adjunct therapeutic options for MDR and XDR tuberculosis. The use of fluoroquinolone-containing (moxifloxacin and gatifloxacin) regimens have failed to shorten duration of therapy, and the new tuberculosis drug pipeline is sparse. Scale-up of existing interventions with increased investments into tuberculosis health services, development of new antituberculosis drugs, adjunct therapies and vaccines, coupled with visionary political leadership, are still our best chance to change the unacceptable status quo of the tuberculosis situation worldwide and the growing problem of drug-resistant tuberculosis.

Cryptococcal meningitis screening and community-based early adherence support in people with advanced HIV infection starting antiretroviral therapy in Tanzania and Zambia: an open-label, randomised controlled trial

BACKGROUND Mortality in people in Africa with HIV infection starting antiretroviral therapy (ART) is high, particularly in those with advanced disease. We assessed the effect of a short period of community support to supplement clinic-based services combined with serum cryptococcal antigen screening. METHODS We did an open-label, randomised controlled trial in six urban clinics in Dar es Salaam, Tanzania, and Lusaka, Zambia. From February, 2012, we enrolled eligible individuals with HIV infection (age ≥18 years, CD4 count of <200 cells per μL, ART naive) and randomly assigned them to either the standard clinic-based care supplemented with community support or standard clinic-based care alone, stratified by country and clinic, in permuted block sizes of ten. Clinic plus community support consisted of screening for serum cryptococcal antigen combined with antifungal therapy for patients testing antigen positive, weekly home visits for the first 4 weeks on ART by lay workers to provide support, and in Tanzania alone, re-screening for tuberculosis at 6-8 weeks after ART initiation. The primary endpoint was all-cause mortality at 12 months, analysed by intention to treat. This trial is registered with the International Standard Randomised Controlled Trial Number registry, number ISCRTN 20410413. FINDINGS Between Feb 9, 2012, and Sept 30, 2013, 1001 patients were randomly assigned to clinic plus community support and 998 to standard care. 89 (9%) of 1001 participants in the clinic plus community support group did not receive their assigned intervention, and 11 (1%) of 998 participants in the standard care group received a home visit or a cryptococcal antigen screen rather than only standard care. At 12 months, 25 (2%) of 1001 participants in the clinic plus community support group and 24 (2%) of 998 participants in the standard care group had been lost to follow-up, and were censored at their last visit for the primary analysis. At 12 months, 134 (13%) of 1001 participants in the clinic plus community support group had died compared with 180 (18%) of 998 in the standard care group. Mortality was 28% (95% CI 10-43) lower in the clinic plus community support group than in standard care group (p=0·004). INTERPRETATION Screening and pre-emptive treatment for cryptococcal infection combined with a short initial period of adherence support after initiation of ART could substantially reduce mortality in HIV programmes in Africa. FUNDING European and Developing Countries Clinical Trials Partnership.

Effect on mortality of point-of-care, urine-based lipoarabinomannan testing to guide tuberculosis treatment initiation in HIV-positive hospital inpatients: a pragmatic, parallel-group, multicountry, open-label, randomised controlled trial

BACKGROUND HIV-associated tuberculosis is difficult to diagnose and results in high mortality. Frequent extra-pulmonary presentation, inability to obtain sputum, and paucibacillary samples limits the usefulness of nucleic-acid amplification tests and smear microscopy. We therefore assessed a urine-based, lateral flow, point-of-care, lipoarabinomannan assay (LAM) and the effect of a LAM-guided anti-tuberculosis treatment initiation strategy on mortality. METHODS We did a pragmatic, randomised, parallel-group, multicentre trial in ten hospitals in Africa--four in South Africa, two in Tanzania, two in Zambia, and two in Zimbabwe. Eligible patients were HIV-positive adults aged at least 18 years with at least one of the following symptoms of tuberculosis (fever, cough, night sweats, or self-reported weightloss) and illness severity necessitating admission to hospital. Exclusion criteria included receipt of any anti-tuberculosis medicine in the 60 days before enrolment. We randomly assigned patients (1:1) to either LAM plus routine diagnostic tests for tuberculosis (smear microscopy, Xpert-MTB/RIF, and culture; LAM group) or routine diagnostic tests alone (no LAM group) using computer-generated allocation lists in blocks of ten. All patients were asked to provide a urine sample of at least 30 mL at enrolment, and trained research nurses did the LAM test in patients allocated to this group using the Alere Determine tuberculosis LAM Ag lateral flow strip test (Alere, USA) at the bedside on enrolment. On the basis of a positive test result, the nurses made a recommendation for initiating anti-tuberculosis treatment. The attending physician made an independent decision about whether to start treatment or not. Neither patients nor health-care workers were masked to group allocation and test results. The primary endpoint was 8-week all-cause mortality assessed in the modified intention-to-treat population (those who received their allocated intervention). This trial is registered with ClinicalTrials.gov, number NCT01770730. FINDINGS Between Jan 1, 2013, and Oct 2, 2014, we screened 8728 patients and randomly assigned 2659 to treatment (1336 to LAM, 1323 to no LAM). 108 patients did not receive their allocated treatment, mainly because they did not meet the inclusion criteria, and 23 were excluded from analysis, leaving 2528 in the final modified intention-to-treat analysis (1257 in the LAM group, 1271 in the no LAM group). Overall all-cause 8-week mortality occurred in 578 (23%) patients, 261 (21%) in LAM and 317 (25%) in no LAM, an absolute reduction of 4% (95% CI 1-7). The risk ratio adjusted for country was 0·83 (95% CI 0·73-0·96), p=0·012, with a relative risk reduction of 17% (95% CI 4-28). With the time-to-event analysis, there were 159 deaths per 100 person-years in LAM and 196 per 100 person-years in no LAM (hazard ratio adjusted for country 0·82 [95% CI 0·70-0·96], p=0·015). No adverse events were associated with LAM testing. INTERPRETATION Bedside LAM-guided initiation of anti-tuberculosis treatment in HIV-positive hospital inpatients with suspected tuberculosis was associated with reduced 8-week mortality. The implementation of LAM testing is likely to offer the greatest benefit in hospitals where diagnostic resources are most scarce and where patients present with severe illness, advanced immunosuppression, and an inability to self-expectorate sputum. FUNDING European Developing Clinical Trials Partnership, the South African Medical Research Council, and the South African National Research Foundation.

Reflections on the white plague.

Tuberculosis continues to be one of the leading causes of morbidity and mortality from infectious disease worldwide. When WHO declared tuberculosis a global emergency in 1993, the initial response from the international community was sluggish and inadequate. A resurgence of the disease, the emergence of multidrug-resistant and extensively drug-resistant strains, and the detrimental effect of the concurrent tuberculosis and HIV/AIDS epidemics on national control programmes in sub-Saharan Africa have all occurred despite the availability of effective combination treatment regimens. On the positive side, funding agencies and donor governments are at long last taking a serious interest in investing in tuberculosis research priorities defined by the Stop TB Partnership. Although this investment introduces optimism for eventual control of the White Plague, past failures remind us not to be complacent.

Antifungal Combinations for Treatment of Cryptococcal Meningitis in Africa

BACKGROUND Cryptococcal meningitis accounts for more than 100,000 human immunodeficiency virus (HIV)–related deaths per year. We tested two treatment strategies that could be more sustainable in Africa than the standard of 2 weeks of amphotericin B plus flucytosine and more effective than the widely used fluconazole monotherapy. METHODS We randomly assigned HIV‐infected adults with cryptococcal meningitis to receive an oral regimen (fluconazole [1200 mg per day] plus flucytosine [100 mg per kilogram of body weight per day] for 2 weeks), 1 week of amphotericin B (1 mg per kilogram per day), or 2 weeks of amphotericin B (1 mg per kilogram per day). Each patient assigned to receive amphotericin B was also randomly assigned to receive fluconazole or flucytosine as a partner drug. After induction treatment, all the patients received fluconazole consolidation therapy and were followed to 10 weeks. RESULTS A total of 721 patients underwent randomization. Mortality in the oral‐regimen, 1‐week amphotericin B, and 2‐week amphotericin B groups was 18.2% (41 of 225), 21.9% (49 of 224), and 21.4% (49 of 229), respectively, at 2 weeks and was 35.1% (79 of 225), 36.2% (81 of 224), and 39.7% (91 of 229), respectively, at 10 weeks. The upper limit of the one‐sided 97.5% confidence interval for the difference in 2‐week mortality was 4.2 percentage points for the oral‐regimen group versus the 2‐week amphotericin B groups and 8.1 percentage points for the 1‐week amphotericin B groups versus the 2‐week amphotericin B groups, both of which were below the predefined 10‐percentage‐point noninferiority margin. As a partner drug with amphotericin B, flucytosine was superior to fluconazole (71 deaths [31.1%] vs. 101 deaths [45.0%]; hazard ratio for death at 10 weeks, 0.62; 95% confidence interval [CI], 0.45 to 0.84; P=0.002). One week of amphotericin B plus flucytosine was associated with the lowest 10‐week mortality (24.2%; 95% CI, 16.2 to 32.1). Side effects, such as severe anemia, were more frequent with 2 weeks than with 1 week of amphotericin B or with the oral regimen. CONCLUSIONS One week of amphotericin B plus flucytosine and 2 weeks of fluconazole plus flucytosine were effective as induction therapy for cryptococcal meningitis in resource‐limited settings. (ACTA Current Controlled Trials number, ISRCTN45035509.)

Genomic epidemiology of Cryptococcus yeasts identifies adaptation to environmental niches underpinning infection across an African HIV/AIDS cohort.

Emerging infections caused by fungi have become a widely recognized global phenomenon and are causing an increasing burden of disease. Genomic techniques are providing new insights into the structure of fungal populations, revealing hitherto undescribed fine‐scale adaptations to environments and hosts that govern their emergence as infections. Cryptococcal meningitis is a neglected tropical disease that is responsible for a large proportion of AIDS‐related deaths across Africa; however, the ecological determinants that underlie a patients risk of infection remain largely unexplored. Here, we use genome sequencing and ecological genomics to decipher the evolutionary ecology of the aetiological agents of cryptococcal meningitis, Cryptococcus neoformans and Cryptococcus gattii, across the central African country of Zambia. We show that the occurrence of these two pathogens is differentially associated with biotic (macroecological) and abiotic (physical) factors across two key African ecoregions, Central Miombo woodlands and Zambezi Mopane woodlands. We show that speciation of Cryptococcus has resulted in adaptation to occupy different ecological niches, with C. neoformans found to occupy Zambezi Mopane woodlands and C. gattii primarily recovered from Central Miombo woodlands. Genome sequencing shows that C. neoformans causes 95% of human infections in this region, of which over three‐quarters belonged to the globalized lineage VNI. We show that VNI infections are largely associated with urbanized populations in Zambia. Conversely, the majority of C. neoformans isolates recovered in the environment belong to the genetically diverse African‐endemic lineage VNB, and we show hitherto unmapped levels of genomic diversity within this lineage. Our results reveal the complex evolutionary ecology that underpins the reservoirs of infection for this, and likely other, deadly pathogenic fungi.

Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing

BackgroundThe commercially available urine LAM strip test, a point-of-care tuberculosis (TB) assay, requires evaluation in a primary care setting where it is most needed. There is currently inadequate data to guide implementation in TB and HIV-endemic settings.MethodsAdult HIV-infected outpatients with suspected pulmonary TB able to self-expectorate sputum from four primary clinics in South Africa, Zambia and Tanzania underwent diagnostic evaluation [sputum smear microscopy, Xpert-MTB/RIF, and culture (reference standard)] as part of a prospective parent study. Urine LAM testing (grade-2 cut-point) was performed on archived samples. Performance characteristics of LAM alone or in combination with sputum—based diagnostics were evaluated. Potential impact on 2 and 6-month morbidity (TBscore), patient dropout rates, and prognosis (death/ loss to follow-up) were evaluated.ResultsAmong 583 participants with suspected TB that were HIV-infected or refused testing, the overall LAM sensitivity (95 % CI; n/N) and in the CD4 ≤ 100 cells/mm3 sub-group was 22.7 % (16.6-28.7; 41/181) and 30.4 % (17.1-43.7; 14/46), respectively. Overall specificity was 93.0 % (90.5-95.6; 361/388). Amongst culture-positive TB cases, adjunctive LAM testing did not improve the sensitivity of either sputum Xpert-MTB/RIF [78.2 % (69.8-86.7; 72/92) versus 76.1 % (67.4-84.8; 70/92), p = 0.7] or smear-microscopy [56.2 % (45.9-66.5; 50/89) versus 43.8 % (33.5-54.1; 39/89), p = 0.1). Clinic-based LAM, as an adjunct to either smear microscopy or Xpert MTB/RIF same-day testing, would neither have decreased patient dropout, nor increased same-day treatment initiation in this clinical setting where same-day chest radiography was available. LAM positivity was associated with 6-month lost-to-follow-up/death (AOR 4.4; p = 0.002) but not TBscore (at baseline or change in TBscore 2-months post-treatment) (p = 0.17).ConclusionsIn African HIV-TB co-infected outpatients able to self-expectorate sputum LAM had limited sensitivity even at low CD4 counts, and offered no significant incremental diagnostic yield over Xpert-MTB/RIF or smear microscopy. In primary care clinics with chest radiography and where empiric TB treatment is common, LAM seems unlikely to improve rates of same-day treatment initiation and patient dropout, however, the ability of LAM to identify patients at high risk of death or lost-to-follow-up may offer important prognostic value.

The biosocial dynamics of tuberculosis

The declaration by the WHO of tuberculosis as a ‘global emergency’ illustrates the paradox of tuberculosis. The treatment of this disease is a good example of ‘evidence‐based medicine’, having been fine‐tuned by numerous clinical trials. Modern short‐course anti‐tuberculosis therapy is among the most effective and cost‐effective ways of saving and prolonging human life; yet, this disease is more prevalent today than in the days before the advent of effective therapy and is currently the cause of one in seven deaths and one in four preventable deaths among young adults. It would seem that something has gone seriously wrong and, to shed light on the cause, it is necessary to take a very broad historical look at the changing trends in the behaviour of the disease in communities worldwide and the attitudes of the various communities to the disease in their midst, not just to understand past mistakes, but to make sure we do not make the same mistakes now and in the future.

Integrating public health research trials into health systems in Africa: individual or cluster randomisation?

Health services in Africa have a very severe shortage of doctors and nurses with fewer than 10 doctors per 100 000 population in several countries (World Health Organization 2006), and access to health services is difficult for many patients because of high transport costs (Govindasamy et al. 2012). Despite these constraints, and the limited experience in delivering chronic care in Africa, antiretroviral therapy (ART) has been scaled up rapidly and about 8 million people are now on treatment (World Health Organization 2013a). In most countries, the HIV services are delivered as stand-alone vertical programmes (Munderi et al. 2012). Non-communicable diseases (NCDs) also require chronic care, and their burden is rising rapidly in Africa (World Health Organization 2009; Lim et al. 2012). The demands for delivering chronic care services will increase substantially (Alleyne et al. 2013), but African health systems are geared towards the control of acute infections (Atun et al. 2013). Research on how to organise and deliver chronic care services in Africa will be essential in order to target the scarce resources efficiently (Ebrahim et al. 2013). Such research has to be integrated into health systems because its central aim is usually to estimate the effectiveness of models of health service delivery under near-normal conditions in order that the findings can be generalised immediately. This is in contrast to many efficacy trials (e.g. of drugs and vaccines), which are usually implemented under parallel systems. We have previously examined the use of cluster randomisation for a vaccine efficacy trial (Jaffar et al. 1999) and examined the operational and ethical issues of integrating research into routine health service delivery (Jaffar et al. 2008). Here we focus on the study design challenges, with a particular focus on whether such trials should be clusteror individually randomised. We examine the issues using our experiences from two trials. The REMSTART trial was designed to evaluate the effectiveness of a complex health service intervention in reducing mortality among HIV-infected patients who presented with very low CD4 count to 6 government clinics in Dar es Salaam, Tanzania, and Lusaka, Zambia (ISCRTN20410413). Enrolment began in February 2012 and ended in September 2013. Follow-up is scheduled to end in September 2014. Initially, only patients with CD4 count <100/ll were eligible for enrolment, but the criterion was changed during the course of the trial to enrol any patient presenting with <200 CD4 cells/ll because of slow recruitment and because of the increasing recognition that such patients had a high risk of death. Just prior to that, the criteria for initiating antiretroviral therapy changed from initiation at CD4 count<200/ll to initiation at CD4 count<350/ll. The World Health Organization has recently recommended that antiretroviral therapy should now be initiated at CD4 count<500 cells/ll (World Health Organization 2013b). The change in recruitment criteria of the REMSTART trial was implemented in September 2012 in Zambia and in December 2012 in Tanzania. The REMSTART trial intervention comprised (i) rapid initiation of antiretroviral therapy, (ii) screening for cryptococcal meningitis using a novel antigen test, (iii) weekly home visits for 4 weeks by trained lay-workers and iv) rescreening for tuberculosis using the Xpert MTB/RIF assay (Cepheid, Sunnyvale, USA) at These authors contributed equally.