A position statement and practical guide to the use of particulate filtering facepiece respirators (N95, FFP2, or equivalent) for South African health workers exposed to respiratory pathogens including Mycobacterium tuberculosis and SARS-CoV-2.

SUMMARY: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted mainly by aerosol in particles <10 µm that can remain suspended for hours before being inhaled. Because particulate filtering facepiece respirators ('respirators'; e.g. N95 masks) are more effective than surgical masks against bio-aerosols, many international organisations now recommend that health workers (HWs) wear a respirator when caring for individuals who may have COVID-19. In South Africa (SA), however, surgical masks are still recommended for the routine care of individuals with possible or confirmed COVID-19, with respirators reserved for so-called aerosol-generating procedures. In contrast, SA guidelines do recommend respirators for routine care of individuals with possible or confirmed tuberculosis (TB), which is also transmitted via aerosol. In health facilities in SA, distinguishing between TB and COVID-19 is challenging without examination and investigation, both of which may expose HWs to potentially infectious individuals. Symptom-based triage has limited utility in defining risk. Indeed, significant proportions of individuals with COVID-19 and/or pulmonary TB may not have symptoms and/or test negative. The prevalence of undiagnosed respiratory disease is therefore likely significant in many general clinical areas (e.g. waiting areas). Moreover, a proportion of HWs are HIV-positive and are at increased risk of severe COVID-19 and death. RECOMMENDATIONS: Sustained improvements in infection prevention and control (IPC) require reorganisation of systems to prioritise HW and patient safety. While this will take time, it is unacceptable to leave HWs exposed until such changes are made. We propose that the SA health system adopts a target of 'zero harm', aiming to eliminate transmission of respiratory pathogens to all individuals in every healthcare setting. Accordingly, we recommend: the use of respirators by all staff (clinical and non-clinical) during activities that involve contact or sharing air in indoor spaces with individuals who: (i) have not yet been clinically evaluated; or (ii) are thought or known to have TB and/or COVID-19 or other potentially harmful respiratory infections;the use of respirators that meet national and international manufacturing standards;evaluation of all respirators, at the least, by qualitative fit testing; andthe use of respirators as part of a 'package of care' in line with international IPC recommendations. We recognise that this will be challenging, not least due to global and national shortages of personal protective equipment (PPE). SA national policy around respiratory protective equipment enables a robust framework for manufacture and quality control and has been supported by local manufacturers and the Department of Trade, Industry and Competition. Respirator manufacturers should explore adaptations to improve comfort and reduce barriers to communication. Structural changes are needed urgently to improve the safety of health facilities: persistent advocacy and research around potential systems change remain essential.

Symptom and digital chest X-ray TB screening in South African prisons: yield and cost-effectiveness.

BACKGROUND: Correctional inmates are at a high risk of tuberculosis (TB). The optimal approach to screening this population is unclear.METHODS: We retrospectively reviewed records from TB screening in 64 correctional facilities in South Africa between January 2015 and July 2016. Inmates received symptom screening (any of cough, fever, weight loss, or night sweats) combined with digital chest X-ray (CXR), when available. CXRs were assessed as 'abnormal' or with no abnormalities. Inmates with either a symptom or an 'abnormal' CXR were asked to provide a single spot sputum for Xpert® MTB/RIF testing. We estimated the incremental cost-effectiveness ratio (ICER) per additional TB case detected using CXR screening among asymptomatic inmates.RESULTS: Of 61 580 inmates, CXR screening was available for 41 852. Of these, 19 711 (47.1%) had TB symptoms. Among 22 141 inmates without symptoms, 1939/19 783 (9.8%) had an abnormal CXR, and 8 (1.2%) were Xpert-positive among those with Xpert tests done. Of 14 942 who received symptom screening only and had symptoms, 84% (12 616) had an Xpert result, and 105 (0.8%) were positive. The ICER for CXR screening was US$22 278.CONCLUSION: Having CXR in addition to symptom screening increased yield but added considerable cost. A major limitation of screening was the low specificity of the symptom screen.

What causes symptoms suggestive of tuberculosis in HIV-positive people with negative initial investigations?

OBJECTIVE: To identify the causes of symptoms suggestive of tuberculosis (TB) among people living with the human immunodeficiency virus (PLHIV) in South Africa. METHODS: A consecutive sample of HIV clinic attendees with symptoms suggestive of TB (1 of cough, weight loss, fever or night sweats) at enrolment and at 3 months, and negative initial TB investigations, were systematically evaluated with standard protocols and diagnoses assigned using standard criteria. TB was 'confirmed' if Mycobacterium tuberculosis was identified within 6 months of enrolment, and 'clinical' if treatment started without microbiological confirmation. RESULTS: Among 103 participants, 50/103 were pre-antiretroviral therapy (ART) and 53/103 were on ART; respectively 68% vs. 79% were female; the median age was 35 vs. 45 years; the median CD4 count was 311 vs. 508 cells/mm³. Seventy-two (70%) had 5% measured weight loss and 50 (49%) had cough. The most common final diagnoses were weight loss due to severe food insecurity (n = 20, 19%), TB (n = 14, 14%: confirmed n = 7; clinical n = 7), other respiratory tract infection (n = 14, 14%) and post-TB lung disease (n = 9, 9%). The basis for TB diagnosis was imaging (n = 7), bacteriological confirmation from sputum (n = 4), histology, lumbar puncture and other (n = 1 each). CONCLUSION: PLHIV with persistent TB symptoms require further evaluation for TB using all available modalities, and for food insecurity in those with weight loss.

Lessons learnt conducting minimally invasive autopsies in private mortuaries as part of HIV and tuberculosis research in South Africa.

Current estimates of the burden of tuberculosis (TB) disease and cause-specific mortality in human immunodeficiency virus (HIV) positive people rely heavily on indirect methods that are less reliable for ascertaining individual-level causes of death and on mathematical models. Minimally invasive autopsy (MIA) is useful for diagnosing infectious diseases, provides a reasonable proxy for the gold standard in cause of death ascertainment (complete diagnostic autopsy) and, used routinely, could improve cause-specific mortality estimates. From our experience in performing MIAs in HIV-positive adults in private mortuaries in South Africa (during the Lesedi Kamoso Study), we describe the challenges we faced and make recommendations for the conduct of MIA in future studies or surveillance programmes, including strategies for effective communication, approaches to obtaining informed consent, risk management for staff and efficient preparation for the procedure.

Les estimations actuelles du poids de la tuberculose (TB) maladie et de la mortalité qui lui est due parmi les patients positifs à l'infection par le virus de l'immunodéficience humaine (VIH) dépendent beaucoup de méthodes indirectes, qui sont moins fiables pour vérifier les causes de décès au niveau individuel et de modèles mathématiques. Une autopsie peu invasive (MIA) est utile au diagnostic de maladies infectieuses, fournit une approximation raisonnable de l'étalon or de la vérification de la cause du décès c'est-à-dire une autopsie diagnostique complète. Si elle est utilisée en routine, elle pourrait améliorer les estimations de mortalité spécifique d'une cause. A partir de nos expériences de MIA sur des adultes positifs au VIH dans des morgues privées d'Afrique du Sud (au cours de l'étude Lesedi Kamoso), nous décrivons les défis rencontrés et faisons des recommandations pour la réalisation de MIA dans des études futures ou des programmes de surveillance, incluant des stratégies de communication efficaces, des approches visant à obtenir un consentement éclairé, une prise en charge du risque pour le personnel et une préparation efficace de la procédure.

Las estimaciones actuales de morbilidad por tuberculosis (TB) y de mortalidad por causas específicas en las personas positivas frente al virus de la inmunodeficiencia humana (VIH) se fundamentan en su mayor parte en métodos indirectos que son menos fiables para determinar las causas de muerte individuales y en modelizaciones matemáticas. La autopsia mínimamente invasiva (MIA) es útil en el diagnóstico de las enfermedades infecciosas, ofrece un sustituto aceptable al método de referencia para determinar la causa de muerte (que es la autopsia diagnóstica completa), y cuando se usa de manera sistemática, mejora las estimaciones de la mortalidad por causas específicas. A partir de su experiencia con la MIA en adultos con infección por el VIH en empresas fúnebres privadas en Suráfrica (durante el estudio Lesedi Kamoso), los autores describen las dificultades que encontraron y formulan recomendaciones que se pueden aplicar en el futuro al realizar la autopsia mínimamente invasiva en estudios de investigación o en programas de vigilancia; se preconizan estrategias de comunicación efectivas, métodos de obtención del consentimiento informado, la gestión de riesgos para el personal y la preparación eficiente del procedimiento.

An intervention to optimise the delivery of integrated tuberculosis and HIV services at primary care clinics: results of the MERGE cluster randomised trial.

OBJECTIVES: To evaluate the effect of an intervention to optimize TB/HIV integration on patient outcomes. METHODS: Cluster randomised control trial at 18 primary care clinics in South Africa. The intervention was placement of a nurse (TB/HIV integration officer) to facilitate provision of integrated TB/HIV services, and a lay health worker (TB screening officer) to facilitate TB screening for 24 months. Primary outcomes were i) incidence of hospitalisation/death among individuals newly diagnosed with HIV, ii) incidence of hospitalisation/death among individuals newly diagnosed with TB and iii) proportion of HIV-positive individuals newly diagnosed with TB who were retained in HIV care 12 months after enrolment. RESULTS: Of 3328 individuals enrolled, 3024 were in the HIV cohort, 731 in TB cohort and 427 in TB-HIV cohort. For the HIV cohort, the hospitalisation/death rate was 12.5 per 100 person-years (py) (182/1459py) in the intervention arm vs. 10.4/100py (147/1408 py) in the control arms respectively (Relative Risk (RR) 1.17 [95% CI 0.92-1.49]).For the TB cohort, hospitalisation/ death rate was 17.1/100 py (67/ 392py) vs. 11.1 /100py (32/289py) in intervention and control arms respectively (RR 1.37 [95% CI 0.78-2.43]). For the TB-HIV cohort, retention in care at 12 months was 63.0% (213/338) and 55.9% (143/256) in intervention and control arms (RR 1.11 [95% 0.89-1.38]). CONCLUSIONS: The intervention as implemented failed to improve patient outcomes beyond levels at control clinics. Effective strategies are needed to achieve better TB/HIV service integration and improve TB and HIV outcomes in primary care clinics. TRIAL REGISTRATION: South African Register of Clinical Trials (registration number DOH-27-1011-3846).

Chronic hepatitis B increases mortality and complexity among HIV-coinfected patients in South Africa: a cohort study.

OBJECTIVES: To assess the effect of chronic hepatitis B on survival and clinical complexity among people living with HIV following antiretroviral therapy (ART) initiation. METHODS: We evaluated mortality and single-drug substitutions up to 3 years from ART initiation (median follow-up 2.75 years; interquartile range 2-3 years) among patients with and without chronic hepatitis B (CHB) enrolled in a workplace HIV care programme in South Africa. RESULTS: Mortality was increased for CHB patients with hepatitis B virus (HBV) DNA levels > 10 000 copies/mL (adjusted hazard ratio 3.1; 95% confidence interval 1.2-8.0) compared with non-CHB patients. We did not observe a similar difference between non-CHB patients and those with CHB and HBV DNA < 10 000 copies/mL (adjusted hazard ratio 0.70; 95% confidence interval 0.2-2.3). Single-drug substitutions occurred more frequently among coinfected patients regardless of HBV DNA level. CONCLUSIONS: Our findings suggest that CHB may increase mortality and complicate ART management.

Implementation and Operational Research: What Happens After a Negative Test for Tuberculosis? Evaluating Adherence to TB Diagnostic Algorithms in South African Primary Health Clinics.

INTRODUCTION AND BACKGROUND: Diagnostic tests for tuberculosis (TB) using sputum have suboptimal sensitivity among HIV-positive persons. We assessed health care worker adherence to TB diagnostic algorithms after negative sputum test results. METHODS: The XTEND (Xpert for TB-Evaluating a New Diagnostic) trial compared outcomes among people tested for TB in primary care clinics using Xpert MTB/RIF vs. smear microscopy as the initial test. We analyzed data from XTEND participants who were HIV positive or HIV status unknown, whose initial sputum Xpert MTB/RIF or microscopy result was negative. If chest radiography, sputum culture, or hospital referral took place, the algorithm for TB diagnosis was considered followed. Analysis of intervention (Xpert MTB/RIF) effect on algorithm adherence used methods for cluster-randomized trials with small number of clusters. RESULTS: Among 4037 XTEND participants with initial negative test results, 2155 (53%) reported being or testing HIV positive and 540 (14%) had unknown HIV status. Among 2155 HIV-positive participants [684 (32%) male, mean age 37 years (range, 18-79 years)], there was evidence of algorithm adherence among 515 (24%). Adherence was less likely among persons tested initially with Xpert MTB/RIF vs. smear [14% (142/1031) vs. 32% (364/1122), adjusted risk ratio 0.34 (95% CI: 0.17 to 0.65)] and for participants with unknown vs. positive HIV status [59/540 (11%) vs. 507/2155 (24%)]. CONCLUSIONS: We observed poorer adherence to TB diagnostic algorithms among HIV-positive persons tested initially with Xpert MTB/RIF vs. microscopy. Poor adherence to TB diagnostic algorithms and incomplete coverage of HIV testing represents a missed opportunity to diagnose TB and HIV, and may contribute to TB mortality.

Pooling sputum from multiple individuals for Xpert® MTB/RIF testing: a strategy for screening high-risk populations.

SETTING: Symptom-based screening for tuberculosis (TB) disease is limited by poor performance of symptom screening in several key populations. We tested the hypothesis that pooling sputum from multiple individuals for Xpert(®) MTB/RIF testing would reduce the number of tests required while retaining an acceptable sensitivity, thus allowing the use of Xpert for TB screening. METHODS: We compared pooling ratios that would require the least number of assays using Xpert and determined that for a population with a TB prevalence of approximately 3%, a 1:5 pooling ratio is optimal. To evaluate sensitivity, we generated pools of one specimen with known Mycobacterium tuberculosis culture positivity (smear microscopy-positive or -negative) with four culture-negative specimens. RESULTS: All 20 of the pools generated from a smear- and culture-positive sputum sample were positive using Xpert. Of the 22 pools with a smear-negative, culture-positive sample, we included 17 in the analysis, of which 13 (76%) were Xpert-positive. CONCLUSIONS: Pooling of sputum samples using Xpert achieved reasonable sensitivity and warrants further evaluation of the systematic screening of high TB prevalence populations.

A cluster randomised trial to evaluate the effect of optimising TB/HIV integration on patient level outcomes: the "merge" trial protocol.

INTRODUCTION: We describe the design of the MERGE trial, a cluster randomised trial, to evaluate the effect of an intervention to optimise TB/HIV service integration on mortality, morbidity and retention in care among newly-diagnosed HIV-positive patients and newly-diagnosed TB patients. DESIGN: Eighteen primary care clinics were randomised to either intervention or standard of care arms. The intervention comprised activities designed to optimise TB and HIV service integration and supported by two new staff cadres-a TB/HIV integration officer and a TB screening officer-for 24 months. A process evaluation to understand how the intervention was perceived and implemented at the clinics was conducted as part of the trial. Newly-diagnosed HIV-positive patients and newly-diagnosed TB patients were enrolled into the study and followed up through telephonic interviews and case note abstractions at six monthly intervals for up to 18 months in order to measure outcomes. The primary outcomes were incidence of hospitalisations or death among newly diagnosed TB patients, incidence of hospitalisation or death among newly diagnosed HIV-positive patients and retention in care among HIV-positive TB patients. Secondary outcomes of the study included measures of cost-effectiveness. DISCUSSION: Methodological challenges of the trial such as implementation of a complex multi-faceted health systems intervention, the measurement of integration at baseline and at the end of the study and an evolving standard of care with respect to TB and HIV are discussed. The trial will contribute to understanding whether TB/HIV service integration affects patient outcomes.

Tuberculosis control in South Africa: successes, challenges and recommendations.

Tuberculosis (TB) remains a global health threat, and South Africa (SA) has one of the world's worst TB epidemics driven by HIV. Among the 22 countries with the highest burden of TB, SA has the highest estimated incidence and prevalence of TB, the second highest number of diagnosed multidrug-resistant TB cases, and the largest number of HIV-associated TB cases. Although SA has made notable progress in reducing TB prevalence and deaths and improving treatment outcomes for new smear-positive TB cases, the burden of TB remains enormous. SA has the means to overcome this situation. In addition to better implementing the basics of TB diagnosis and treatment, scaling up the use of Xpert MTB/RIF as a replacement for sputum smear microscopy, strengthening case finding in and beyond healthcare facilities and a greater focus on TB prevention for people living with HIV, particularly earlier initiation of and scaling up antiretroviral therapy and scaling up continuous isoniazid preventive therapy, will have a substantial impact on TB control. New TB drugs, diagnostics and vaccines are required to further accelerate progress towards improved TB control in SA and beyond.

Isoniazid preventive therapy use among patients on antiretroviral therapy: a missed opportunity.

Isoniazid preventive therapy (IPT) with antiretroviral therapy (ART) reduces incident tuberculosis among patients infected with the human immunodeficiency virus. We describe IPT use among patients on ART at two primary care clinics in South Africa. Of 597 participants interviewed, 100 (16.8%) reported IPT use; 73.4% (365/497) with no reported IPT use were eligible for IPT. IPT use was associated with age <35 years (aOR 1.90, 95%CI 1.18-3.06), and receiving care at one clinic as opposed to the other (aOR 4.72, 95%CI 2.69-7.93). The high proportion of patients on ART eligible for IPT represents a missed opportunity for IPT scale-up.

Spectrum of non-tuberculous mycobacteria identified using standard biochemical testing vs. 16S sequencing.

Non-tuberculous mycobacterial isolates from gold miners were speciated using standard biochemical testing (SBT) and 16S rDNA sequencing. Of 237 isolates tested, SBT identified 126, compared with all 237 identified using sequencing. Of 111 isolates unspeciated by SBT but identified by sequencing, 38 (34.2%) were identified as Mycobacterium gordonae and 8 (7.2%) were new species. Of 126 isolates speciated by both methods, 37 were discordant, with 14/17 M. gordonae isolates incorrectly identified as M. scrofulaceum using SBT. The majority of these were the potentially pathogenic strain D, M. gordonae. Sequencing is preferable where available to guide treatment.

Designing an adaptive phase II/III trial to evaluate efficacy, safety and immune correlates of new TB vaccines in young adults and adolescents.

This article summarises the consensus arrived at a meeting of South African and international stakeholders on specific late phase clinical trial design issues integrating the investigation of immune correlates as an integral part of a phase III protocol for a preventative TB vaccine in an adolescent/adult population. The challenge ahead is to optimize the planning for phase 3 TB vaccine preventative trials, under resource constraints, given that there are no known correlates of protection to shorten and increase the efficiencies of efficacy trials. An adaptive, multi-arm, group sequentially designed trial protocol is proposed incorporating design features that address uncertainties arising from both advances in the field and dynamic study populations and disease states. Such a design allows modifications that protect research subjects, save time, and maximize the impact of scarce financial resources. Further, the protocol underwent joint review by regulators from several African nations at a meeting of the African Vaccine Regulatory Forum (AVAREF), a regional regulatory harmonization initiative, and recommendations are included.

Tuberculosis among adults starting antiretroviral therapy in South Africa: the need for routine case finding.

OBJECTIVE: To investigate the prevalence of and evaluate screening modalities for undiagnosed tuberculosis (TB) in antiretroviral therapy (ART) eligible adults in South Africa. METHODS: Individuals were screened for TB using symptoms, chest radiograph (CXR) and two sputum specimens for microscopy and culture, and were then followed for <6 months to determine TB diagnoses. RESULTS: Among 361 participants (67% female, median age 38 years, median CD4 count 120 cells/mm(3)), 64 (18%) were sputum culture-positive; 114 (32%) fulfilled any TB case definition (culture- and/or smear-positive, or improvement on specific treatment). Symptom screening comprising any of cough, appetite loss or night sweats > 2 weeks had a sensitivity and specificity of respectively 74.5% and 50.8%. Sensitivity was increased by CXR (to 96.1%), but not by smear microscopy. The World Health Organization symptom screen had a sensitivity and specificity of respectively 96.1% and 5.2% in our study population; the addition of CXR increased sensitivity to 100%. Median time to TB treatment was 8 days for diagnoses based on CXR (n = 72) vs. 37 days for diagnoses based only on sputum culture (n = 14). CONCLUSIONS: The very high prevalence of undiagnosed TB among patients presenting for ART mandates their routine investigation. CXR improved sensitivity substantially, allowed rapid treatment initiation and should be routine, where available, pending better point-of-care diagnostics.

Key issues in the clinical development and implementation of TB vaccines in South Africa.

Significant progress has been made in advancing the development pipeline for a new and more effective TB vaccine with some candidate vaccines now in late stage clinical evaluation. However, progress has been hampered by an incomplete understanding of the components of a protective immune response and limited animal models, rendering the field unable to reliably predict vaccine efficacy earlier in preclinical development, including by evaluation in animal models, and limiting the predictive utility of comparing immunogenic effects across vaccine candidates in phase I/II studies. Consequently, new candidate vaccines have to be evaluated for efficacy in large-scale phase II/III trials using clinical endpoints. Apart from the technical challenges of characterising TB incidence in target populations at high risk of acquiring TB disease and standardising case definitions in order to improve both the sensitivity and more importantly the specificity of trial endpoints, there is an urgency in expanding and supporting the considerable trial infrastructure that will be required to evaluate and ultimately license a new TB vaccine. In the longer term, implementation strategies are dependent on what policy makers most value. Economic analyses will be essential to guide policy and implementation. This paper outlines the gaps and challenges and identifies solutions for effectively developing and efficiently introducing a new TB vaccine.

Trends in drug-resistant tuberculosis in a gold-mining workforce in South Africa, 2002-2008.

SETTING AND OBJECTIVE: To describe trends in drug-resistant tuberculosis (TB) in two gold-mining workforces, South Africa, 2002-2008. DESIGN: TB programme data analysis. RESULTS: TB case notification rates decreased between 2002 and 2008 from 4006 to 3018 per 100,000 and from 3192 to 2468/100,000 for Companies A and B, respectively. Human immunodeficiency virus (HIV) prevalence exceeded 80% in TB episodes with known status. The proportion of TB episodes with multidrug-resistant TB (MDR-TB) increased from 6/129 (4.7%) to 17/85 (20.0%) among previously treated cases, and from 4/38 (10.4%) to 7/28 (25.0%) in Companies A and B, respectively (tests for trend, Company A, P < 0.001; Company B, P = 0.304). Case notifications of MDR-TB increased during 2002-2008 from 39.8 to 122.9/100,000/year in Company A and from 7.8 to 96.8/100,000/year in Company B. Coverage of second-line drug susceptibility testing (DST) among MDR-TB episodes was low. Previous treatment exposure was a strong risk factor for MDR-TB (prevalence ratio 8.78, 95%CI 5.94-12.97 in previously treated vs. untreated individuals). CONCLUSION: Despite decreasing TB notifications overall, MDR-TB notifications and proportions of episodes with MDR-TB increased in the larger company. Cure must be ensured in first episodes to prevent acquired resistance. Improved coverage of culture, DST and HIV testing is required to allow treatment to be optimised.

Lung function loss in relation to silica dust exposure in South African gold miners.

OBJECTIVE: To estimate exposure-response relationships between respirable dust, respirable quartz and lung function loss in black South African gold miners. METHODS: 520 mineworkers aged >37 years were enrolled in a cross-sectional study. Gravimetric dust measurements were used to calculate cumulative respirable dust and quartz exposures. Excess lung function loss was defined as predicted minus observed forced expiratory volume in one second (FEV(1)) and forced vital capacity (FVC). The association between excess loss and exposure was estimated, adjusting for smoking, tuberculosis and silicosis. RESULTS: Mean service length was 21.8 years, mean respirable dust 0.37 mg/m(3) and mean respirable quartz 0.053 mg/m(3). After adjustment, 1 mg-yr/m(3) increase in cumulative respirable dust exposure was associated with 18.7 ml mean excess loss in FVC [95% confidence interval (CI) 0.3, 37.1] and 16.2 ml in FEV1 (95% CI -0.3, 32.6). Mean excess loss with silicosis was 224.1 ml in FEV1 and 123.6 ml in FVC; with tuberculosis 347.4 ml in FEV1 and 264.3 ml in FVC. CONCLUSION: Despite a healthy worker effect, lung function loss was demonstrable whether due to silicosis, tuberculosis or an independent effect of dust. A miner working at a respirable dust intensity of 0.37 mg/m(3) for 30 years would lose on average an additional 208 ml in FVC (95% CI 3, 412) in the absence of other disease, an impact greater than that of silicosis and comparable to that of tuberculosis. Improved dust control on the South African gold mines would reduce the risk of silicosis, tuberculosis and lung function impairment.

Excess lung function decline in gold miners following pulmonary tuberculosis.

BACKGROUND: Few if any studies of the association between pulmonary tuberculosis (TB) and lung function loss have had access to premorbid lung function values. METHODS: Using a retrospective cohort design, the study recruited employed South African gold miners who had undergone a pulmonary function test (PFT) between January 1995 and August 1996. The 'exposed' group comprised 185 miners treated for pulmonary TB after the initial PFT and the 'unexposed' group comprised 185 age-matched miners without TB. All participants had a follow-up PFT between April and June 2000. The outcome of interest was decline in lung function during the follow-up period as measured by forced vital capacity (FVC) and forced expiratory volume in 1 s(FEV(1)). RESULTS: After controlling for age, height, baseline lung function, silicosis, years of employment, smoking and other respiratory diagnoses, pulmonary TB during the follow-up period was associated with a mean excess loss of 40.3 ml/year in FEV(1) (95% CI 25.4 to 55.1) and 42.7 ml/year in FVC (95% CI 27.0 to 58.5). Lung function loss was greater among those with more severe or later clinical presentation of TB. Breathlessness was twice as common among TB cases (OR 2.20, 95% CI 1.18 to 4.11). CONCLUSION: There is a need for greater clinical recognition of the long-term respiratory consequences of treated pulmonary TB. Early detection of TB would help to reduce these sequelae and remains a priority, particularly in a workforce already subject to silica dust disease. However, strategies such as dust control, worker education about TB and dust and TB preventive therapy are also needed to avert the disease itself.