Implementation and Operational Research: Use of Symptom Screening and Sputum Microscopy Testing for Active Tuberculosis Case Detection Among HIV-Infected Patients in Real-World Clinical Practice in Uganda

Tuberculosis diagnosis cascade in Blantyre, Malawi: a prospective cohort study

BACKGROUND

Tuberculosis (TB) control relies on early diagnosis and treatment. International guidelines recommend systematic TB screening at health facilities, but implementation is challenging. We investigated completion of recommended TB screening steps in Blantyre, Malawi.

METHODS

A prospective cohort recruited adult outpatients attending Bangwe primary clinic. Entry interviews were linked to exit interviews. The proportion of participants progressing through each step of the diagnostic pathway were estimated. Factors associated with request for sputum were investigated using multivariable logistic regression.

RESULTS

Of 5442 clinic attendances 2397 (44%) had exit interviews. In clinically indicated participants (n = 445) 256 (57.5%) were asked about cough, 36 (8.1%) were asked for sputum, 21 (4.7%) gave sputum and 1 (0.2%) received same-day results. Significant associations with request for sputum were: any TB symptom (aOR:3.20, 95%CI:2.02-5.06), increasing age (aOR:1.02, 95%CI:1.01-1.04 per year) and for HIV-negative participants only, a history of previous TB (aOR:3.37, 95%CI:1.45-7.81). Numbers requiring sputum tests (26/day) outnumbered diagnostic capacity (8-12/day).

CONCLUSIONS

Patients were lost at every stage of the TB care cascade, with same day sputum submission following all steps of the diagnosis cascade achieved in only 4.7% if clinically indicated. Infection control strategies should be implemented, with reporting on early steps of the TB care cascade formalised. High-throughput screening interventions, such as digital CXR, that can achieve same-day TB diagnosis are urgently needed to meet WHO End TB goals.

Tuberculosis preventive treatment opportunities at antiretroviral therapy initiation and follow-up visits

Setting

Twenty-two clinics providing HIV care and treatment in Botswana where tuberculosis (TB) and HIV comorbidity is as high as 49%.

Objectives

To assess eligibility of TB preventive treatment (TPT) at antiretroviral therapy (ART) initiation and at four follow-up visits (FUVs), and to describe the TB prevalence and associated factors at baseline and yield of TB diagnoses at each FUV.

Design

A prospective study of routinely collected data on people living with HIV (PLHIV) enrolled into care for the Xpert^® MTB/RIF Package Rollout Evaluation Study between 2012 and 2015.

Results

Of 6041 PLHIV initiating ART, eligibility for TPT was 69% (4177/6041) at baseline and 93% (5408/5815); 95% (5234/5514); 96% (4869/5079); and 97% (3925/4055) at FUV1, FUV2, FUV3, and FUV4, respectively. TB prevalence at baseline was 11% and 2%, 3%, 3% and 6% at each subsequent FUV. At baseline, independent risk factors for prevalent TB were CD4 <200 cells/mm³ (aOR = 1.4, P = 0.030); anemia (aOR = 2.39, P < 0.001); cough (aOR = 11.21, P < 0.001); fever (aOR = 2.15, P = 0.001); and weight loss (aOR = 2.60, P = 0.002).

Conclusion

Eligibility for TPT initiation is higher at visits post-ART initiation, while most cases of active TB were identified at ART initiation. Missed opportunities for TB further compromises TB control effort among PLHIV in Botswana.

Mortality Among People With HIV Treated for Tuberculosis Based on Positive, Negative, or No Bacteriologic Test Results for Tuberculosis: The IeDEA Consortium

Background

In resource-constrained settings, many people with HIV (PWH) are treated for tuberculosis (TB) without bacteriologic testing. Their mortality compared with those with bacteriologic testing is uncertain.

Methods

We conducted an observational cohort study among PWH ≥15 years of age initiating TB treatment at sites affiliated with 4 International epidemiology Databases to Evaluate AIDS consortium regions from 2012 to 2014: Caribbean, Central and South America, and Central, East, and West Africa. The exposure of interest was the TB bacteriologic test status at TB treatment initiation: positive, negative, or no test result. The hazard of death in the 12 months after TB treatment initiation was estimated using a Cox proportional hazard model. Missing covariate values were multiply imputed.

Results

In 2091 PWH, median age 36 years, 53% had CD4 counts ≤200 cells/mm³, and 52% were on antiretroviral therapy (ART) at TB treatment initiation. The adjusted hazard of death was higher in patients with no test compared with those with positive test results (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.08–2.26). The hazard of death was also higher among those with negative compared with positive tests but was not statistically significant (HR, 1.28; 95% CI, 0.91–1.81). Being on ART, having a higher CD4 count, and tertiary facility level were associated with a lower hazard for death.

Conclusions

There was some evidence that PWH treated for TB with no bacteriologic test results were at higher risk of death than those with positive tests. Research is needed to understand the causes of death in PWH treated for TB without bacteriologic testing.

Guidance for Studies Evaluating the Accuracy of Tuberculosis Triage Tests

Approximately 3.6 million cases of active tuberculosis (TB) go potentially undiagnosed annually, partly due to limited access to confirmatory diagnostic tests, such as molecular assays or mycobacterial culture, in community and primary healthcare settings. This article provides guidance for TB triage test evaluations. A TB triage test is designed for use in people with TB symptoms and/or significant risk factors for TB. Triage tests are simple and low-cost tests aiming to improve ease of access and implementation (compared with confirmatory tests) and decrease the proportion of patients requiring more expensive confirmatory testing. Evaluation of triage tests should occur in settings of intended use, such as community and primary healthcare centers. Important considerations for triage test evaluation include study design, population, sample type, test throughput, use of thresholds, reference standard (ideally culture), and specimen flow. The impact of a triage test will depend heavily on issues beyond accuracy, primarily centered on implementation.

Quality matters: Redefining child TB care with an emphasis on quality

Children have been neglected in the fight against tuberculosis (TB) for decades. Despite being the number one infectious disease killer, TB does not feature on the child survival agendas partly due to absent and inaccurate data. Quality is a missing ingredient in TB care in children, yet high rates of unfavorable TB outcomes highlight its importance in this age group. Quality care is particularly important for TB affected children in the absence of a point of care sensitive and specific diagnostic test. Using the current models of child TB care, it will take another 200 years to end TB. Without focusing on the quality of child TB care, the ambitious country specific United Nations High Level Meeting for TB targets will carry minimal impact. High TB burden countries must also adopt Universal Health Care (UHC) and ensure that quality TB care is made free and equitable for all children, adolescents and their affected families. We advocate for the importance of evaluating the quality of child TB care, and provide a basic framework for quality in child TB with special attention given to creating differentiated service delivery models for children and families affected by TB.

Completion of the tuberculosis care cascade in a community-based HIV linkage-to-care study in South Africa and Uganda

INTRODUCTION

Tuberculosis (TB) is the leading cause of HIV-associated mortality in Africa. As HIV testing, linkage to care and antiretroviral treatment initiation intensify to meet UNAIDS targets, it is not known what effect these efforts will have on TB detection and prevention. We aimed to characterize the TB care cascade of screening, diagnostic testing, treatment and provision of isoniazid preventive therapy (IPT) in a study of community-based HIV screening and linkage to care and determine whether symptom screening results affected progress along the cascade.

METHODS

Between June 2013 and March 2015, HIV-infected adults enrolled in the Linkages study, a multi-site, community-based, randomized HIV screening and linkage-to-care study in South Africa and Uganda. All participants were screened for TB symptoms at entry after testing positive for HIV and referred to local clinics for care. During the 9 month follow-up, participants were periodically surveyed about clinic linkage and initiation of HIV care as well as subsequent TB testing, treatment, or IPT. We compared outcomes between persons with and without a positive symptom screen at baseline using descriptive statistics and Poisson regression to calculate relative risks of outcomes along the care cascade.

RESULTS AND DISCUSSION

Of the 1,325 HIV-infected adults enrolled, 26% reported at least one TB symptom at the time of HIV diagnosis. Loss of appetite and fever were the most commonly reported symptoms on a TB symptom screen. Despite 92% HIV linkage success, corresponding TB linkage was incomplete. Baseline TB symptoms were associated with an increased risk of a TB diagnosis (relative risk 3.23, 95% CI 1.51 to 6.91), but only 34% of symptomatic persons had sputum TB testing. Fifty-five percent of participants diagnosed with TB started TB treatment. In South Africa, only 18% of asymptomatic participants initiated IPT after linkage to HIV care, and presence of symptoms was not associated with IPT initiation (relative risk 0.86 95% CI 0.6 to 1.23).

CONCLUSIONS

HIV linkage to care interventions provide an opportunity to improve completion of the TB care cascade, but will require additional support to realize full benefits.

C-reactive protein as a screening test for HIV-associated pulmonary tuberculosis prior to antiretroviral therapy in South Africa

BACKGROUND

There is an urgent need for more accurate screening tests for tuberculosis(TB). We assessed the diagnostic accuracy of C-reactive protein (CRP) as a screening test for active TB in HIV-infected ambulatory adults.

METHODS

CRP levels were measured in blood collected at the time of HIV testing.Diagnostic accuracy of CRP for pulmonary TB was calculated (reference standard: TB culture), compared to the WHO 4-symptom screen, consisting of cough, fever, night sweats, and weight loss. Diagnostic accuracy was also calculated for CRP in a larger cohort of HIV-infected adults with a positive symptom screen (reference standard: clinical or microbiological TB).

RESULTS

Among 425 HIV-infected outpatients systematically tested for pulmonary TB, TB culture was positive in 42 (10%), 279 (66%) had at least one TB-related symptom and 197 (46%) had a CRP more than 5 mg/l. The sensitivity of CRP and the TB symptom screen to detect TB was the same [90.5%; 95% confidence interval 77.4-97.3] but specificity of CRP was higher than for the TB symptom screen (58.5% vs. 37.1%, P < 0.001). Of persons with no symptoms and normal CRP, 99 (98%) had no TB. In another cohort of 749 patients presenting with at least one TB-related symptom and clinically evaluated, CRP had a sensitivity of 98.7% and specificity of 48.3%.

CONCLUSION

In HIV-infected outpatients, CRP was as sensitive but substantially more specific than TB symptom screening. Use of CRP as a screening tool to exclude active TB could identify the same number of HIV-associated TB cases, but reduce the use of diagnostic sputum testing in TB-endemic regions.

Tuberculosis Case Finding With Combined Rapid Point-of-Care Assays (Xpert MTB/RIF and Determine TB LAM) in HIV-Positive Individuals Starting Antiretroviral Therapy in Mozambique

Background

Tuberculosis is a major health concern in several countries, and effective diagnostic algorithms for use in human immunodeficiency virus (HIV)-positive patients are urgently needed.

Methods

At prescription of antiretroviral therapy, all patients in 3 Mozambican health centers were screened for tuberculosis, with a combined approach: World Health Organization (WHO) 4-symptom screening (fever, cough, night sweats, and weight loss), a rapid test detecting mycobacterial lipoarabinomannan in urine (Determine TB LAM), and a molecular assay performed on a sputum sample (Xpert MTB/RIF; repeated if first result was negative). Patients with positive LAM or Xpert MTB/RIF results were referred for tuberculosis treatment.

Results

Among 972 patients with a complete diagnostic algorithm (58.5% female; median CD4 cell count, 278/μL; WHO HIV stage I, 66.8%), 98 (10.1%) tested positive with Xpert (90, 9.3%) or LAM (34, 3.5%) assays. Compared with a single-test Xpert strategy, dual Xpert tests improved case finding by 21.6%, LAM testing alone improved it by 13.5%, and dual Xpert tests plus LAM testing improved it by 32.4%. Rifampicin resistance in Xpert-positive patients was infrequent (2.5%). Among patients with positive results, 22 of 98 (22.4%) had no symptoms at WHO 4-symptom screening. Patients with tuberculosis diagnosed had significantly lower CD4 cell counts and hemoglobin levels, more advanced WHO stage, and higher HIV RNA levels. Fifteen (15.3%) did not start tuberculosis treatment, mostly owing to rapidly deteriorating clinical conditions or logistical constraints. The median interval between start of the diagnostic algorithm and start of tuberculosis treatment was 7 days.

Conclusions

The prevalence of tuberculosis among Mozambican HIV-positive patients starting antiretroviral therapy was 10%, with limited rifampicin resistance. Use of combined point-of-care tests increased case finding, with a short time to treatment. Interventions are needed to remove logistical barriers and prevent presentation in very advanced HIV/tuberculosis disease.