Operational modelling: the mechanisms influencing TB diagnostic yield in an Xpert MTB/RIF-based algorithm

SETTING: Cape Town, South Africa. OBJECTIVE: To compare the diagnostic yield for smear/culture and Xpert® MTB/RIF algorithms and to investigate the mechanisms influencing tuberculosis (TB) yield. METHOD: We developed and validated an operational model of the TB diagnostic process, first with the smear/culture algorithm and then with the Xpert algorithm. We modelled scenarios by varying TB prevalence, adherence to diagnostic algorithms and human immunodeficiency virus (HIV) status. This enabled direct comparisons of diagnostic yield in the two algorithms to be made. RESULTS: Routine data showed that diagnostic yield had decreased over the period of the Xpert algorithm roll-out compared to the yield when the smear/culture algorithm was in place. However, modelling yield under identical conditions indicated a 13.3% increase in diagnostic yield from the Xpert algorithm compared to smear/culture. The model demonstrated that the extensive use of culture in the smear/culture algorithm and the decline in TB prevalence are the main factors contributing to not finding an increase in diagnostic yield in the routine data. CONCLUSION: We demonstrate the benefits of an operational model to determine the effect of scale-up of a new diagnostic algorithm, and recommend that policy makers use operational modelling to make appropriate decisions before new diagnostic algorithms are scaled up

Patient Diagnostic Rate as Indicator of Tuberculosis Case Detection, South Africa.

To address the uncertainty of the indirectly measured tuberculosis case detection rate, we used survey data stratified by HIV status to calculate the patient diagnostic rate, a directly measurable indicator, in 8 communities in South Africa. Rates were lower among HIV-negative than HIV-positive persons. Tuberculosis programs should focus on HIV-negative persons

Missed opportunities for retention in pre-ART care in Cape Town, South Africa

BACKGROUND: Few studies have evaluated access to and retention in pre-ART care. Objectives To evaluate the proportion of People Living With HIV (PLWH) in pre-ART and ART care and factors associated with retention in pre-ART and ART care from a community cohort. METHODS: A cross sectional survey was conducted from February - April 2011. Self reported HIV positive, negative or participants of unknown status completed a questionnaire on their HIV testing history, access to pre-ART and retention in pre-ART and ART care. RESULTS: 872 randomly selected adults who reported being HIV positive in the ZAMSTAR 2010 prevalence survey were included and revisited. 579 (66%) reconfirmed their positive status and were included in this analysis. 380 (66%) had initiated ART with 357 of these (94%) retained in ART care. 199 (34%) had never initiated ART of whom 186 (93%) accessed pre-ART care, and 86 (43%) were retained in pre-ART care. In a univariable analysis none of the factors analysed were significantly associated with retention in care in the pre-ART group. Due to the high retention in ART care, factors associated with retention in ART care, were not analysed further. CONCLUSION: Retention in ART care was high; however it was low in pre-ART care. The opportunity exists, if care is better integrated, to engage with clients in primary health care facilities to bring them back to, and retain them in, pre-ART care

Morbidity and mortality up to 5 years post tuberculosis treatment in South Africa: a pilot study

Background A high risk of tuberculosis (TB), chronic lung disease, and mortality have been reported among people with a history of previous TB treatment, but data from high-incidence settings remain limited. The aim of this study was to characterize general morbidity and mortality among adults who had successfully completed TB treatment in the past 5 years in a high-incidence setting in South Africa. Methods Adults (≥18 years) who had completed treatment for pulmonary TB between 2013 and 2017 were randomly selected from TB treatment registers. Household visits were conducted to locate and interview former TB (FTB) patients, and bacteriological testing for TB was offered. Additional data sources were used to ascertain the vitality status of FTB patients who could not be located. Results Addresses were located for 200 of the 223 FTB patients sampled and 89 FTB patients were contacted of whom 51 agreed to be interviewed. Approximately half reported persistent respiratory symptoms, such as shortness of breath and wheezing, and repeated lung infections. One (3.6%) of 28 patients who provided a sputum sample had culture-positive TB and another two were currently on re-treatment for TB. Fifteen deaths post treatment were ascertained, resulting in a standardized mortality ratio of 3.8 (95% confidence interval 2.3–6.3) after successful TB treatment relative to the general population. Conclusions In this high-incidence setting, locating and interviewing FTB patients was challenging. The study findings are consistent with a high rate of respiratory disease, including recurrent TB, and substantially elevated mortality among FTB patients

Retention in care and factors critical for effectively implementing antiretroviral adherence clubs in a rural district in South Africa

CITATION: Bock, P., et al. 2019. Retention in care and factors critical for effectively implementing antiretroviral adherence clubs in a rural district in South Africa. Journal of the International AIDS Society, 22(10):e25396, doi:10.1002/jia2.25396.The original publication is available at https://onlinelibrary.wiley.comPublication of this article was funded by the Stellenbosch University Open Access FundIntroduction: Differentiated models of care that include referral of antiretroviral treatment (ART) clients to adherence clubs are an important strategy to help clinics manage increased number of clients living with HIV in resource-constrained settings. This study reported on (i) clinical outcomes among ART clients attending community-based adherence clubs and (ii) experiences of adherence clubs and perceptions of factors key to successful adherence club implementation among clients and healthcare workers. Methods: A retrospective cohort analysis of routine data and a descriptive analysis of data collected through self-administered surveys completed by clients and healthcare workers were completed. Clients starting ART at the study clinic, between January 2014 and December 2015, were included in the cohort analysis and followed up until December 2016. The survey data were collected from August to September 2017. The primary outcome for the cohort analysis was a comparison of loss to follow-up (LTFU) between clients staying in clinic care and those referred to adherence clubs. Survey data reported on client experiences of and healthcare worker perceptions of adherence club care. Results: Cohort analysis reported on 465 participants, median baseline CD4 count 374 (IQR: 234 to 532) cells/ll and median follow-up time 20.7 (IQR 14.1 to 27.7) months. Overall, 202 (43.4%) participants were referred to an adherence club. LTFU was lower in those attending an adherence club (aHR =0.25, 95% CI: 0.11 to 0.56). This finding was confirmed on analysis restricted to those eligible for adherence club referral (aHR =0.28, 95% CI: 0.12 to 0.65). Factors highlighted as associated with successful adherence club implementation included: (i) referral of stable clients to the club, (ii) an ideal club size of ≥20 members, (iii) club services led by a counsellor (iv) using churches or community halls as venues (v) effective communication between all parties, and (vi) timely delivery of prepacked medication. Conclusions: This study showed good clinical outcomes, positive patient experiences and healthcare worker perceptions of the adherence club model. Factors associated with successful adherence club implementation, highlighted in this study, can be used to guide implementers in the scale-up of adherence club services across varied high-burden settings.ns202011https://onlinelibrary.wiley.com/doi/full/10.1002/jia2.25396Publisher's versio

Mortality in South African children and adolescents routinely treated for tuberculosis

BACKGROUND: In South Africa, tuberculosis (TB) is a leading cause of death among those abstract, 20 years of age. We describe changes in TB mortality among children and adolescents in South Africa over a 13-year period, identify risk factors for mortality, and estimate excess TBrelated mortality. METHODS: Retrospective analysis of all patients ,20 years of age routinely recorded in the national electronic drug-susceptible TB treatment register (2004–2016). We developed a multivariable Cox regression model for predictors of mortality and used estimates of mortality among the general population to calculate standardized mortality ratios (SMRs). RESULTS: Between 2004 and 2016, 729 463 children and adolescents were recorded on TB treatment; 84.0% had treatment outcomes and 2.5% (18 539) died during TB treatment. The case fatality ratio decreased from 3.3% in 2007 to 1.9% in 2016. In the multivariable Cox regression model, ages 0 to 4, 10 to 14, and 15 to 19 years (compared with ages 5 to 9 years) were associated with increased risk of mortality, as was HIV infection, previous TB treatment, and extrapulmonary involvement. The SMR of 15 to 19-year-old female patients was more than double that of male patients the same age (55.3 vs 26.2). Among 10 to 14-year-olds and those who were HIV-positive

Mortality during tuberculosis treatment in South Africa using an 8-year analysis of the national tuberculosis treatment register

n 2011, the South African HIV treatment eligibility criteria were expanded to allow all tuberculosis (TB) patients lifelong ART. The impact of this change on TB mortality in South Africa is not known. We evaluated mortality in all adults (≥ 15 years old) treated for drug-susceptible TB in South Africa between 2009 and 2016. Using a Cox regression model, we quantified risk factors for mortality during TB treatment and present standardised mortality ratios (SMR) stratified by year, age, sex, and HIV status. During the study period, 8.6% (219,618/2,551,058) of adults on TB treatment died. Older age, male sex, previous TB treatment and HIV infection (with or without the use of ART) were associated with increased hazard of mortality. There was a 19% reduction in hazard of mortality amongst all TB patients between 2009 and 2016 (adjusted hazard ratio: 0.81 95%CI 0.80–0.83). The highest SMR was in 15–24-year-old women, more than double that of men (42.3 in 2016). Between 2009 and 2016, the SMR for HIV-positive TB patients increased, from 9.0 to 19.6 in women, and 7.0 to 10.6 in men. In South Africa, case fatality during TB treatment is decreasing and further interventions to address specific risk factors for TB mortality are required. Young women (15–24-year olds) with TB experience a disproportionate burden of mortality and interventions targeting this age-group are needed

Associations between HIV stigma and health-related quality-of-life among people living with HIV: cross-sectional analysis of data from HPTN 071 (PopART)

People living with HIV (PLHIV) report lower health-related quality-of-life (HRQoL) than HIV-negative people. HIV stigma may contribute to this. We explored the association between HIV stigma and HRQoL among PLHIV. We used cross-sectional data from 3991 randomly selected PLHIV who were surveyed in 2017–2018 for HPTN 071 (PopART), a cluster randomised trial in Zambia and South Africa. Participants were 18–44 years, had laboratory-confirmed HIV infection, and knew their status. HRQoL was measured using the EuroQol-5-dimensions-5-levels (EQ-5D-5L) questionnaire. Stigma outcomes included: internalised stigma, stigma experienced in the community, and stigma experienced in healthcare settings. Associations were examined using logistic regression. Participants who had experienced community stigma (n = 693/3991) had higher odds of reporting problems in at least one HRQoL domain, compared to those who had not (adjusted odds ratio, aOR: 1.51, 95% confidence interval, 95% Cl: 1.16–1.98, p = 0.002). Having experienced internalised stigma was also associated with reporting problems in at least one HRQoL domain (n = 552/3991, aOR: 1.98, 95% CI: 1.54–2.54, p < 0.001). However, having experienced stigma in a healthcare setting was less common (n = 158/3991) and not associated with HRQoL (aOR: 1.04, 95% CI: 0.68–1.58, p = 0.850). A stronger focus on interventions for internalised stigma and stigma experienced in the community is required

Effect of household and community interventions on the burden of tuberculosis in southern Africa: the ZAMSTAR community-randomised trial.

BACKGROUND: Southern Africa has had an unprecedented increase in the burden of tuberculosis, driven by the HIV epidemic. The Zambia, South Africa Tuberculosis and AIDS Reduction (ZAMSTAR) trial examined two public health interventions that aimed to reduce the burden of tuberculosis by facilitating either rapid sputum diagnosis or integrating tuberculosis and HIV services within the community. METHODS: ZAMSTAR was a community-randomised trial done in Zambia and the Western Cape province of South Africa. Two interventions, community-level enhanced tuberculosis case-finding (ECF) and household level tuberculosis-HIV care, were implemented between Aug 1, 2006, and July 31, 2009, and assessed in a 2×2 factorial design between Jan 9, 2010, and Dec 6, 2010. All communities had a strengthened tuberculosis-HIV programme implemented in participating health-care centres. 24 communities, selected according to population size and tuberculosis notification rate, were randomly allocated to one of four study groups using a randomisation schedule stratified by country and baseline prevalence of tuberculous infection: group 1 strengthened tuberculosis-HIV programme at the clinic alone; group 2, clinic plus ECF; group 3, clinic plus household intervention; and group 4, clinic plus ECF and household interventions. The primary outcome was the prevalence of culture-confirmed pulmonary tuberculosis in adults (≥18 years), defined as Mycobacterium tuberculosis isolated from one respiratory sample, measured 4 years after the start of interventions in a survey of 4000 randomly selected adults in each community in 2010. The secondary outcome was the incidence of tuberculous infection, measured using tuberculin skin testing in a cohort of schoolchildren, a median of 4 years after a baseline survey done before the start of interventions. This trial is registered, number ISRCTN36729271. FINDINGS: Prevalence of tuberculosis was evaluated in 64,463 individuals randomly selected from the 24 communities; 894 individuals had active tuberculosis. Averaging over the 24 communities, the geometric mean of tuberculosis prevalence was 832 per 100,000 population. The adjusted prevalence ratio for the comparison of ECF versus non-ECF intervention groups was 1·09 (95% CI 0·86-1·40) and of household versus non-household intervention groups was 0·82 (0·64-1·04). The incidence of tuberculous infection was measured in a cohort of 8809 children, followed up for a median of 4 years; the adjusted rate ratio for ECF versus non-ECF groups was 1·36 (95% CI 0·59-3·14) and for household versus non-household groups was 0·45 (0·20-1·05). INTERPRETATION: Although neither intervention led to a statistically significant reduction in tuberculosis, two independent indicators of burden provide some evidence of a reduction in tuberculosis among communities receiving the household intervention. By contrast the ECF intervention had no effect on either outcome. FUNDING: Bill & Melinda Gates Foundation

Indirect reciprocity and the evolution of “moral signals”

Signals regarding the behavior of others are an essential element of human moral systems and there are important evolutionary connections between language and large-scale cooperation. In particular, social communication may be required for the reputation tracking needed to stabilize indirect reciprocity. Additionally, scholars have suggested that the benefits of indirect reciprocity may have been important for the evolution of language and that social signals may have coevolved with large-scale cooperation. This paper investigates the possibility of such a coevolution. Using the tools of evolutionary game theory, we present a model that incorporates primitive “moral signaling” into a simple setting of indirect reciprocity. This model reveals some potential difficulties for the evolution of “moral signals.” We find that it is possible for “moral signals” to evolve alongside indirect reciprocity, but without some external pressure aiding the evolution of a signaling system, such a coevolution is unlikely