Browsing by Author "van Zyl-Smit, Richard"

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    Open Access
    Challenges For Dedicated Smoking Cessation Services In Developing Countries
    (2020) Tadzimirwa, Gamuchirai Y; van Zyl-Smit, Richard
    Background South Africa, the country ranked as the ‘second most stressful country to live in' has an estimated 7 million smokers. A dedicated smoking cessation clinic established at Groote Schuur Hospital, Cape Town, provides the only clinical service and training centre in the country. Objectives To evaluate the smokers attending the clinic, in order to better understand the requirements of smoking cessation services in resource-limited settings. Methods Demographic and smoking-related data was collected prospectively from all clinic attendees since its inception. Nicotine dependence, depression scores and exhaled carbon monoxide levels were formally evaluated. Consent was provided to review the collected data. Results Ninety-seven smokers were evaluated. Their mean(standard deviation)age 50.9(10.9)years, and 59% (57/97) were male. The median age of smoking initiation was 16(interquartile range(IQR) 8 - 28) with a current median daily consumption of 12(IQR 7-20). Overall men smoked more than women, with a median of 20( cigarettes per day(IQR 10 - 20) v 12( IQR 5 - 20) respectively (p=0.001). The median Fagerström nicotine dependence score was 5(IQR 3 - 7), with scores of 6(IQR 4 - 8) for men and 5(IQR 2 - 7) for women (p=0.06); 50% of smokers had a Fagerström score < 6(low to above-average dependence) and 22% a score of ≥8 (extreme dependence). The median Patient Health Questionnaire9(PHQ-9) depression score was 8(IQR 4 - 11), and 49% of smokers had symptoms of at least minor depression (score ≥10). The clinic could not provide pharmacotherapy. The self-reported quit rate was 28% at median follow up of 22 months(IQR 14 -39). Conclusions In smokers attempting to quit, moderate levels of nicotine dependence coexist with significant depression and anxiety symptoms. These data inform resource allocation and public health strategies, suggesting that in resource-limited smoking cessation services, psychological/behavioural support focusing on depressive symptoms may be a greater priority than simple pharmacotherapy.
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    Comparison of same day diagnostic tools including Gene Xpert and unstimulated IFN-γ for the evaluation of pleural tuberculosis: a prospective cohort study
    (BioMed Central, 2014-04-08) Meldau, Richard; Peter, Jonny; Theron, Grant; Calligaro, Greg; Allwood, Brian; Symons, Greg; Khalfey, Hoosain; Ntombenhle, Gina; Govender, Ureshnie; Binder, Anke; van Zyl-Smit, Richard; Dheda, Keertan
    Background: The accuracy of currently available same-day diagnostic tools (smear microscopy and conventional nucleic acid amplification tests) for pleural tuberculosis (TB) is sub-optimal. Newer technologies may offer improved detection. Methods: Smear-microscopy, adenosine deaminase (ADA), interferon gamma (IFN-γ), and Xpert MTB/RIF [using an unprocessed (1 ml) and centrifuged (~20 ml) sample] test accuracy was evaluated in pleural fluid from 103 consecutive patients with suspected pleural TB. Culture for M.tuberculosis and/or histopathology (pleural biopsy) served as the reference standard. Patients were followed prospectively to determine their diagnostic categorisation. Results: Of 93 evaluable participants, 40 had definite-TB (reference positive), 5 probable-TB (not definite but treated for TB) and 48 non-TB (culture and histology negative, and not treated for TB). Xpert MTB/RIF sensitivity and specificity (95% CI) was 22.5% (12.4 - 37.6) and 98% (89.2 - 99.7), respectively, and centrifugation did not improve sensitivity (23.7%). The Xpert MTB/RIF internal positive control showed no evidence of inhibition. Biomarker specific sensitivity, specificity, PPV, and NPVs were: ADA (48.85 IU/L; rule-in cut-point) 55.3% (39.8 - 69.9), 95.2% (83.9 - 98.7), 91.4 (73.4 - 95.4), 69.7% (56.7 - 80.1); ADA (30 IU/L; clinically used cut-point) 79% (63.7 - 89), 92.7% (80.6 - 97.5), 91.0 (73.4 - 95.4), 82.7% (69.3 - 90.1); and IFN-γ (107.7 pg/ml; rule-in cut-point) 92.5% (80.2 - 97.5), 95.9% (86.1 - 98.9), 94.9% (83.2 - 98.6), 93.9% (83.5 - 97.9), respectively (IFN-γ sensitivity and NPV better than Xpert [p < 0.05] and rule-in ADA [p < 0.05]). Conclusion: The usefulness of Xpert MTB/RIF to diagnose pleural TB is limited by its poor sensitivity. IFN-γ is an excellent rule-in test and, compared to ADA, has significantly better sensitivity and rule-out value in a TB-endemic setting.
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    Correlation of mycobacterium tuberculosis specific and non-specific quantitative Th1 T-cell responses with bacillary load in a high burden setting
    (Public Library of Science, 2012) Theron, Grant; Peter, Jonny; Lenders, Laura; van Zyl-Smit, Richard; Meldau, Richard; Govender, Ureshnie; Dheda, Keertan
    BACKGROUND: Measures of bacillary load in patients with tuberculosis (TB) may be useful for predicting and monitoring response to treatment. The relationship between quantitative T-cell responses and mycobacterial load remains unclear. We hypothesised that, in a HIV-prevalent high burden setting, the magnitude of mycobacterial antigen-specific and non-specific T-cell IFN-γ responses would correlate with (a) bacterial load and (b) culture conversion in patients undergoing treatment. METHODS: We compared baseline (n = 147), 2 (n = 35) and 6 month (n = 13) purified-protein-derivative (PPD) and RD1-specific (TSPOT.TB and QFT-GIT) blood RD1-specific (TSPOT.TB; QFT-GIT) responses with associates of sputum bacillary load in patients with culture-confirmed TB in Cape Town, South Africa. RESULTS: IFN-γ responses were not associated with liquid culture time-to-positivity, smear-grade, Xpert MTB/RIF-generated cycle threshold values or the presence of cavities on the chest radiograph in patients with culture-confirmed TB and irrespective of HIV-status. 2-month IGRA conversion rates (positive-to-negative) were negligible [<11% for TSPOT.TB (3/28) and QFT-GIT (1/29)] and lower compared to culture [60% (21/35); p<0.01]. CONCLUSIONS: In a high burden HIV-prevalent setting T-cell IFN-γ responses to M. tuberculosis- specific and non-specific antigens do not correlate with bacillary load, including Xpert MTB/RIF-generated C T values, and are therefore poorly suited for monitoring treatment and prognostication.
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    Development of a simple reliable radiographic scoring system to aid the diagnosis of pulmonary tuberculosis
    (Public Library of Science, 2013) Pinto, Lancelot M; Dheda, Keertan; Theron, Grant; Allwood, Brian; Calligaro, Gregory; van Zyl-Smit, Richard; Peter, Jonathan; Schwartzman, Kevin; Menzies, Dick; Bateman, Eric; Pai, Madhukar; Dawson, Rodney
    Rationale: Chest radiography is sometimes the only method available for investigating patients with possible pulmonary tuberculosis (PTB) with negative sputum smears. However, interpretation of chest radiographs in this context lacks specificity for PTB, is subjective and is neither standardized nor reproducible. Efforts to improve the interpretation of chest radiography are warranted. Objectives To develop a scoring system to aid the diagnosis of PTB, using features recorded with the Chest Radiograph Reading and Recording System (CRRS). METHODS: Chest radiographs of outpatients with possible PTB, recruited over 3 years at clinics in South Africa were read by two independent readers using the CRRS method. Multivariate analysis was used to identify features significantly associated with culture-positive PTB. These were weighted and used to generate a score. RESULTS: 473 patients were included in the analysis. Large upper lobe opacities, cavities, unilateral pleural effusion and adenopathy were significantly associated with PTB, had high inter-reader reliability, and received 2, 2, 1 and 2 points, respectively in the final score. Using a cut-off of 2, scores below this threshold had a high negative predictive value (91.5%, 95%CI 87.1,94.7), but low positive predictive value (49.4%, 95%CI 42.9,55.9). Among the 382 TB suspects with negative sputum smears, 229 patients had scores <2; the score correctly ruled out active PTB in 214 of these patients (NPV 93.4%; 95%CI 89.4,96.3). The score had a suboptimal negative predictive value in HIV-infected patients (NPV 86.4, 95% CI 75,94). CONCLUSIONS: The proposed scoring system is simple, and reliably ruled out active PTB in smear-negative HIV-uninfected patients, thus potentially reducing the need for further tests in high burden settings. Validation studies are now required.