Mareli Claassens

Prof. Mareli Claassens

orcid

Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2013 in The Lancet
Verified
Journal Article
Closed access
HAHelen Ayles
Helen Ayles
MMMonde Muyoyeta
Monde Muyoyeta
ETElizabeth Du Toit
Elizabeth Du Toit
ASAb Schaap
Ab Schaap
SFSian Floyd
Sian Floyd
PGPeter Godfrey-Faussett
Peter Godfrey-Faussett

19 January 2022 in Journal of Epidemiology and Community Health
Verified
Journal Article
Open access
PDF file
TATom Achoki
Tom Achoki
Benn SartoriusBenn Sartorius
Benn Sartorius
DWDavid Watkins
David Watkins
SGScott D Glenn
Scott D Glenn
AKAndre Pascal Kengne
Andre Pascal Kengne
MNMohsen Naghavi
Mohsen Naghavi
Background Over the last 30 years, South Africa has experienced four ‘colliding epidemics’ of HIV and tuberculosis, chronic illness and mental health, injury and violence, and maternal, neonatal, and child mortality, which have had substantial effects on health and well-being. Using data from the 2019 Global Burden of Diseases, Injuries and Risk Factors Study (GBD 2019), we evaluated national and provincial health trends and progress towards important Sustainable Development Goal targets from 1990 to 2019. Methods We analysed GBD 2019 estimates of mortality, non-fatal health loss, summary health measures and risk factor burden, comparing trends over 1990–2007 and 2007–2019. Additionally, we decomposed changes in life expectancy by cause of death and assessed healthcare system performance. Results Across the nine provinces, inequalities in mortality and life expectancy increased over 1990–2007, largely due to differences in HIV/AIDS, then decreased over 2007–2019. Demographic change and increases in non-communicable diseases nearly doubled the number of years lived with disability between 1990 and 2019. From 1990 to 2019, risk factor burdens generally shifted from communicable and nutritional disease risks to non-communicable disease and injury risks; unsafe sex remained the top risk factor. Despite widespread improvements in healthcare system performance, the greatest gains were generally in economically advantaged provinces. Conclusions Reductions in HIV/AIDS and related conditions have led to improved health since 2007, though most provinces still lag in key areas. To achieve health targets, provincial governments should enhance health investments and exchange of knowledge, resources and best practices alongside populations that have been left behind, especially following the COVID-19 pandemic.

1 June 2012 in The International Journal of Tuberculosis and Lung Disease
Verified
Journal Article
Closed access
AKA. H. J. Kolk
A. H. J. Kolk
JBJ. J. B. N. van Berkel
J. J. B. N. van Berkel
Mareli ClaassensMareli Claassens
Mareli Claassens
EWE. Walters
E. Walters
SKS. Kuijper
S. Kuijper
FSF. J. van Schooten
F. J. van Schooten
Cape Town, South Africa. We investigated the potential of breath analysis by gas chromatography-mass spectrometry (GC-MS) to discriminate between samples collected prospectively from patients with suspected tuberculosis (TB). Samples were obtained in a TB-endemic setting in South Africa, where 28% of culture-proven TB patients had Ziehl-Neelsen (ZN) negative sputum smear. A training set of breath samples from 50 sputum culture-proven TB patients and 50 culture-negative non-TB patients was analysed using GC-MS. We used support vector machine analysis for classification of the patient samples into TB and non-TB. A classification model with seven compounds had a sensitivity of 72%, a specificity of 86% and an accuracy of 79% compared with culture. The classification model was validated with breath samples from a different set of 21 TB and 50 non-TB patients from the same area, giving a sensitivity of 62%, a specificity of 84% and an accuracy of 77%. This study shows that GC-MS breath analysis is able to differentiate between TB and non-TB breath samples even among patients with a negative ZN sputum smear but a positive culture for Mycobacterium tuberculosis. We conclude that breath analysis by GC-MS merits further research.

25 November 2016 in BMC Infectious Diseases
Verified
Journal Article
Open access
PDF file
DSDonald Skinner
Donald Skinner
Mareli ClaassensMareli Claassens
Mareli Claassens
Individuals who test positive for active tuberculosis (TB) but do not initiate treatment present a challenge to TB programmes because they contribute to ongoing transmission within communities. To better understand why individuals do not initiate treatment, or are adherent after initiating treatment, South African respondents were approached to obtain insights as to which factors enabled and inhibited the treatment process. This qualitative work was nested in a larger study investigating initial loss to follow-up (LTFU) amongst new smear positive TB patients across five provinces of South Africa. In-depth interviews were done with 41 adherent and initial LTFU respondents. Key issues contributing to initial LTFU appeared to be a poor knowledge, or low awareness of TB treatment; stigma around TB including its connection to HIV; immediate problems in the respondents’ lives particularly poverty, lack of access to transport and the need to continue working; and problems in the healthcare facilities including under resourced facilities, poor functioning health systems and negative staff attitudes. In contrast the reasons given for being adherent related to the level of illness, support received at home and healthcare facilities, a belief in the health system and positive experiences in the health service including positive attitudes from staff. Key changes need to be made to the healthcare system to enable patients to initiate treatment and remain adherent, but the six month regimen of daily observed treatment presents real practical and personal challenges to patients. Alternative strategies to DOTS at facility level should be investigated to bring services closer to communities to encourage patients to access care, initiate and adhere to treatment.

2 October 2013 in PLOS ONE
Verified
Journal Article
Open access
PDF file
Mareli ClaassensMareli Claassens
Mareli Claassens
CSCari Van Schalkwyk
Cari Van Schalkwyk
ETElizabeth Du Toit
Elizabeth Du Toit
EREline Roest
Eline Roest
CLCarl J Lombard
Carl J Lombard
MBMartien W Borgdorff
Martien W Borgdorff
Challenges exist regarding TB infection control and TB in hospital-based healthcare workers in South Africa. However, few studies report on TB in non-hospital based healthcare workers such as primary or community healthcare workers. Our objectives were to investigate the implementation of TB infection control measures at primary healthcare facilities, the smear positive TB incidence rate amongst primary healthcare workers and the association between TB infection control measures and all types of TB in healthcare workers. One hundred and thirty three primary healthcare facilities were visited in five provinces of South Africa in 2009. At each facility, a TB infection control audit and facility questionnaire were completed. The number of healthcare workers who had had TB during the past three years was obtained. The standardised incidence ratio of smear positive TB in primary healthcare workers indicated an incidence rate of more than double that of the general population. In a univariable logistic regression, the infection control audit score was significantly associated with reported cases of TB in healthcare workers (OR=1.04, 95%CI 1.01-1.08, p=0.02) as was the number of staff (OR=3.78, 95%CI 1.77-8.08). In the multivariable analysis, the number of staff remained significantly associated with TB in healthcare workers (OR=3.33, 95%CI 1.37-8.08). The high rate of TB in healthcare workers suggests a substantial nosocomial transmission risk, but the infection control audit tool which was used did not perform adequately as a measure of this risk. Infection control measures should be monitored by validated tools developed and tested locally. Different strategies, such as routine surveillance systems, could be used to evaluate the burden of TB in healthcare workers in order to calculate TB incidence, monitor trends and implement interventions to decrease occupational TB.

1 March 2018 in The International Journal of Tuberculosis and Lung Disease
Verified
Journal Article
Closed access
PKP. F. Kweza
P. F. Kweza
CSC. Van Schalkwyk
C. Van Schalkwyk
NAN. Abraham
N. Abraham
MUM. Uys
M. Uys
Mareli ClaassensMareli Claassens
Mareli Claassens
AMA. Medina-Marino
A. Medina-Marino
SETTING: The present study was conducted at 20 randomly selected primary health clinics across Buffalo City Metropolitan Health District, a high TB burden district in South Africa. OBJECTIVE: To estimate the proportion of TB patients missed by primary health clinics. DESIGN: We enrolled 1255 TB-symptomatic individuals exiting primary health clinics between March and December 2015. Participants were interviewed and asked to provide sputum for Xpert® MTB/RIF testing. RESULTS: Clinic staff screened 79.1% of participants seeking care for TB-related symptoms and 21.9% of those attending a clinic for other reasons (P < 0.001). Of those screened by clinic staff, 21.5% reported submitting sputum, although only 9.8% had available results. Study staff tested sputum from 779 participants not tested by clinic staff. Of these, 39 (5.0%) individuals tested positive for TB, three of whom were rifampicin-resistant; 15/39 (38.5%) were never screened and 24/39 (61.5%) were screened but not tested by clinic staff. We estimate that the health system missed 62.9–78.5% of TB patients attending primary health clinics for TB-related symptoms and 89.5–100% of those attending a clinic for other reasons. CONCLUSION: Low rates of TB screening and testing by the health system resulted in missed TB patients. Universal TB screening and testing of symptomatic individuals should be instituted in high TB burden communities in South Africa.