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Dive into the research topics where Tonya M. Esterhuizen is active.

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Featured researches published by Tonya M. Esterhuizen.


JAMA | 2014

Efficacy of varenicline combined with nicotine replacement therapy vs varenicline alone for smoking cessation: a randomized clinical trial.

Coenraad F.N. Koegelenberg; Firdows Noor; Eric D. Bateman; Richard van Zyl-Smit; Axel Bruning; John A. O’Brien; Clifford W. Smith; Mohamed S. Abdool-Gaffar; Shaunagh Emanuel; Tonya M. Esterhuizen; Elvis M. Irusen

IMPORTANCE Behavioral approaches and pharmacotherapy are of proven benefit in assisting smokers to quit, but it is unclear whether combining nicotine replacement therapy (NRT) with varenicline to improve abstinence is effective and safe. OBJECTIVE To evaluate the efficacy and safety of combining varenicline and a nicotine patch vs varenicline alone in smoking cessation. DESIGN, SETTING, AND PARTICIPANTS Randomized, blinded, placebo-controlled clinical trial with a 12-week treatment period and a further 12-week follow-up conducted in 7 centers in South Africa from April 2011 to October 2012. Four hundred forty-six generally healthy smokers were randomized (1:1); 435 were included in the efficacy and safety analyses. INTERVENTIONS Nicotine or placebo patch treatment began 2 weeks before a target quit date (TQD) and continued for a further 12 weeks. Varenicline was begun 1 week prior to TQD, continued for a further 12 weeks, and tapered off during week 13. MAIN OUTCOMES AND MEASURES Tobacco abstinence was established and confirmed by exhaled carbon monoxide measurements at TQD and at intervals thereafter up to 24 weeks. The primary end point was the 4-week exhaled carbon monoxide-confirmed continuous abstinence rate for weeks 9 through 12 of treatment, ie, the proportion of participants able to maintain complete abstinence from smoking for the last 4 weeks of treatment, as assessed using multiple imputation analysis. Secondary end points included point prevalence abstinence at 6 months, continuous abstinence rate from weeks 9 through 24, and adverse events. Multiple imputation also was used to address loss to follow-up. RESULTS The combination treatment was associated with a higher continuous abstinence rate at 12 weeks (55.4% vs 40.9%; odds ratio [OR], 1.85; 95% CI, 1.19-2.89; P = .007) and 24 weeks (49.0% vs 32.6%; OR, 1.98; 95% CI, 1.25-3.14; P = .004) and point prevalence abstinence rate at 6 months (65.1% vs 46.7%; OR, 2.13; 95% CI, 1.32-3.43; P = .002). In the combination treatment group, there was a numerically greater incidence of nausea, sleep disturbance, skin reactions, constipation, and depression, with only skin reactions reaching statistical significance (14.4% vs 7.8%; P = .03); the varenicline-alone group experienced more abnormal dreams and headaches. CONCLUSIONS AND RELEVANCE Varenicline in combination with NRT was more effective than varenicline alone at achieving tobacco abstinence at 12 weeks (end of treatment) and at 6 months. Further studies are needed to assess long-term efficacy and safety. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01444131.


South African Medical Journal | 2015

Investigating the association between diabetes mellitus, depression and psychological distress in a cohort of South African teachers

Abdul Kader Domingo; Laila Asmal; Soraya Seedat; Tonya M. Esterhuizen; Carien Laurence; Jimmy Volmink

BACKGROUND Diabetes mellitus (DM) may increase the risk of depression as a result of a sense of threat of debilitating complications or because of associated lifestyle changes. Depression may increase the risk of type 2 diabetes as a result of poor health behaviours. OBJECTIVE To determine the association between diabetes mellitus, depression and psychological distress in a cohort of South African (SA) teachers. METHODS Teachers from 111 public schools in the Metro South District of the Cape Metropolitan area, SA, were invited to participate in this study. The Center for Epidemiologic Studies Depression Scale (CES-D) and the Kessler Psychological Distress Scale (K10) were used to assess depression and psychological distress, respectively. A professional nurse completed a physical examination and collected blood for measurement of glucose, cholesterol and serum creatinine. RESULTS Of the 388 teachers who completed the questionnaires, 67.5% were female and the average age was 46.2 years (standard deviation 8.7). Psychological distress was identified in 28.1% of the cohort and depression in 15.5%, and 7.7% were found to fulfil criteria for DM. A diagnosis of DM was associated with an increased risk of depression (adjusted odds ratio (AOR) 3.90; 95% confidence interval (CI) 1.33-11.37) and psychological distress (AOR 3.62; 95% CI 1.31-10.00). CONCLUSION The high prevalence of obesity and DM in this cohort of SA teachers is of concern. A diagnosis of DM was strongly associated with an increased risk of depression and psychological distress.


PLOS ONE | 2016

Burden of diabetes and first evidence for the utility of HbA1c for diagnosis and detection of diabetes in urban Black South Africans : the Durban diabetes study

Thomas R. Hird; Fraser Pirie; Tonya M. Esterhuizen; Brian O’Leary; Mark I. McCarthy; Elizabeth H. Young; Manjinder S. Sandhu; Ayesha A. Motala

Objective Glycated haemoglobin (HbA1c) is recommended as an additional tool to glucose-based measures (fasting plasma glucose [FPG] and 2-hour plasma glucose [2PG] during oral glucose tolerance test [OGTT]) for the diagnosis of diabetes; however, its use in sub-Saharan African populations is not established. We assessed prevalence estimates and the diagnosis and detection of diabetes based on OGTT, FPG, and HbA1c in an urban black South African population. Research Design and Methods We conducted a population-based cross-sectional survey using multistage cluster sampling of adults aged ≥18 years in Durban (eThekwini municipality), KwaZulu-Natal. All participants had a 75-g OGTT and HbA1c measurements. Receiver operating characteristic (ROC) analysis was used to assess the overall diagnostic accuracy of HbA1c, using OGTT as the reference, and to determine optimal HbA1c cut-offs. Results Among 1190 participants (851 women, 92.6% response rate), the age-standardised prevalence of diabetes was 12.9% based on OGTT, 11.9% based on FPG, and 13.1% based on HbA1c. In participants without a previous history of diabetes (n = 1077), using OGTT as the reference, an HbA1c ≥48 mmol/mol (6.5%) detected diabetes with 70.3% sensitivity (95%CI 52.7–87.8) and 98.7% specificity (95%CI 97.9–99.4) (AUC 0.94 [95%CI 0.89–1.00]). Additional analyses suggested the optimal HbA1c cut-off for detection of diabetes in this population was 42 mmol/mol (6.0%) (sensitivity 89.2% [95%CI 78.6–99.8], specificity 92.0% [95%CI: 90.3–93.7]). Conclusions In an urban black South African population, we found a high prevalence of diabetes and provide the first evidence for the utility of HbA1c for the diagnosis and detection of diabetes in black Africans in sub-Saharan Africa.


Ocular Immunology and Inflammation | 2018

The Prevalence of Intraocular Tuberculosis in HIV-positive and HIV-negative Patients in South Africa Using a Revised Classification System

Derrick P. Smit; Tonya M. Esterhuizen; David Meyer

ABSTRACT Purpose: To report the prevalence of intraocular tuberculosis in South Africa using a revised classification system. Methods: A prospective study to determine the underlying etiology in patients presenting with uveitis to a tertiary Eye Clinic. Results: A total of 35 out of 106 patients (33.0%) were diagnosed with intraocular tuberculosis, of which 11 (31.4%) had HIV infection; 23 patients (65.7%) had possible intraocular tuberculosis and 12 (34.3%) had probable intraocular tuberculosis. Patients with probable intraocular tuberculosis were younger than those with possible intraocular tuberculosis (p = 0.003). More males (66.7%) had probable intraocular tuberculosis and more females (73.9%) had possible intraocular tuberculosis (p = 0.031). More HIV-positive patients had probable intraocular tuberculosis and more HIV-negative patients had possible intraocular tuberculosis (p = 0.002). Conclusions: South Africa has a high prevalence of intraocular tuberculosis. Younger, male, HIV-positive patients are more likely to have probable intraocular tuberculosis, while older, female, HIV-negative patients are more likely to have possible intraocular tuberculosis.


PLOS ONE | 2015

The influence of second-hand cigarette smoke exposure during childhood and active cigarette smoking on crohn’s disease phenotype defined by the montreal classification scheme in a Western Cape population, South Africa

Tawanda Chivese; Tonya M. Esterhuizen; Abigail Raffner Basson

Background Smoking may worsen the disease outcomes in patients with Crohn’s disease (CD), however the effect of exposure to second-hand cigarette smoke during childhood is unclear. In South Africa, no such literature exists. The aim of this study was to investigate whether disease phenotype, at time of diagnosis of CD, was associated with exposure to second-hand cigarette during childhood and active cigarette smoking habits. Methods A cross sectional examination of all consecutive CD patients seen during the period September 2011-January 2013 at 2 large inflammatory bowel disease centers in the Western Cape, South Africa was performed. Data were collected via review of patient case notes, interviewer-administered questionnaire and clinical examination by the attending gastroenterologist. Disease phenotype (behavior and location) was evaluated at time of diagnosis, according to the Montreal Classification scheme. In addition, disease behavior was stratified as ‘complicated’ or ‘uncomplicated’, using predefined definitions. Passive cigarette smoke exposure was evaluated during 3 age intervals: 0–5, 6–10, and 11–18 years. Results One hundred and ninety four CD patients were identified. Cigarette smoking during the 6 months prior to, or at time of diagnosis was significantly associated with ileo-colonic (L3) disease (RRR = 3.63; 95%CI, 1.32–9.98, p = 0.012) and ileal (L1) disease (RRR = 3.54; 95%CI, 1.06–11.83, p = 0.040) compared with colonic disease. In smokers, childhood passive cigarette smoke exposure during the 0–5 years age interval was significantly associated with ileo-colonic CD location (RRR = 21.3; 95%CI, 1.16–391.55, p = 0.040). No significant association between smoking habits and disease behavior at diagnosis, whether defined by the Montreal scheme, or stratified as ‘complicated’ vs ‘uncomplicated’, was observed. Conclusion Smoking habits were associated with ileo-colonic (L3) and ileal (L1) disease at time of diagnosis in a South African cohort.


BMJ Global Health | 2018

User assessments and the use of information from MomConnect, a mobile phone text-based information service, by pregnant women and new mothers in South Africa

Donald Skinner; Peter Delobelle; Michele Pappin; Desiree Pieterse; Tonya M. Esterhuizen; Peter Barron; Lilian Dudley

MomConnect was designed to provide crucial health information to mothers during pregnancy and in the early years of child rearing in South Africa. The design drew on the success of the Mobile Alliance for Maternal Action’s programme in South Africa, as well as a growing list of mobile health (mHealth) interventions implemented internationally. Services such as MomConnect are dependent on user acceptability as all engagements are voluntary, meaning that tools have to be easy to use and useful to be successful. This paper describes the evaluation of the tool by pregnant women and new mothers using the tool. A purposive sample of 32 individual semistructured interviews and 7 focus groups were conducted, across five provinces in South Africa. All the sessions were transcribed and then analysed using a contextualised interpretative approach, with the assistance of Atlas.ti. The women were consistently positive about MomConnect, attaching high value to the content of the messages and the medium in which they were delivered. The system was found to work well, with minor problems in some language translations. Respondents were enthusiastic about the messages, stating that the information was of great use and made them feel empowered in their role as a mother, with some saving the messages to use as a resource or to share with others. The most significant problems related to network coverage. There was strong support for this intervention to continue. Given the user acceptability of mHealth interventions, MomConnect appeared to meet the target of identifying and responding to the recipient’s needs.


BMC Family Practice | 2018

The perceived impact of family physicians on the district health system in South Africa : a cross-sectional survey

Klaus B. von Pressentin; Robert Mash; Laurel Baldwin-Ragaven; Roelf Petrus Gerhardus Botha; Indiran Govender; Wilhelm Johannes Steinberg; Tonya M. Esterhuizen

BackgroundEvidence from first world contexts support the notion that strong primary health care teams contain family physicians (FPs). African leaders are looking for evidence from their own context. The roles and scope of practice of FPs are also contextually defined. The South African family medicine discipline has agreed on six roles. These roles were incorporated into a family physician impact assessment tool, previously validated in the Western Cape Province.MethodsA cross-sectional study design was used to assess the perceived impact of family physicians across seven South African provinces. All FPs working in the district health system (DHS) of these seven provinces were invited to participate. Sixteen respondents (including the FP) per enrolled FP were asked to complete the validated 360-degree assessment tool.ResultsA total number of 52 FPs enrolled for the survey (a response rate of 56.5%) with a total number of 542 respondents. The mean number of respondents per FP was 10.4 (SD = 3.9). The perceived impact made by FPs was high for five of the six roles. Co-workers rated their FP’s impact across all six roles as higher, compared to the other doctors at the same facility. The perceived beneficial impact was experienced equally across the whole study setting, with no significant differences when comparing location (rural vs. metropolitan), facility type or training model (graduation before and ≥ 2011).ConclusionsThe findings support the need to increase the deployment of family physicians in the DHS and to increase the number being trained as per the national position paper.


Journal of Clinical Microbiology | 2015

Sputum Volume Predicts Sputum Mycobacterial Load during the First 2 Weeks of Antituberculosis Treatment

Miriam N. Karinja; Tonya M. Esterhuizen; Sven O. Friedrich; Andreas H. Diacon

ABSTRACT Disease severity in patients with pulmonary tuberculosis is associated with mycobacterial sputum load. To ascertain whether reduced sputum production during treatment is a useful clinical sign of improvement, we analyzed the mycobacterial loads of 5,552 sputum samples collected from 439 newly diagnosed sputum smear-positive tuberculosis patients who participated in six 14-day studies of antituberculosis treatment. Sputum volumes were categorized as low (<6 ml), medium (6 to 10 ml), or large (>10 ml), and mycobacterial load was measured by the time to positivity in liquid culture and the CFU counts on solid culture. The association of sputum volume with mycobacterial load was estimated with multiple linear regression models adjusted for repeated measures. The predictor variables were sputum volume category, treatment day, specific study , and the interaction of sputum volume category and treatment day. Mycobacterial load was significantly associated only with the day on treatment and sputum volume, which tended to decrease with ongoing treatment. With the volume held constant, each day on treatment decreased the log CFU by 0.082 (P < 0.001) and increased the time to positivity (TTP) by 1.04 h (P < 0.001). From low to medium and from medium to large sputum volumes, the log CFU/ml increased by 0.265 (P < 0.003) and 0.490 (P < 0.001), respectively, and the TTP decreased by 1.17 h (P < 0.001) and 1.30 h (P < 0.001), respectively, for a given day of treatment. The variability of the sputum load measurements increased with the day of treatment and lower sputum volumes. The significant association of sputum volume and mycobacterial load validates decreasing sputum production as a clinical sign of improvement during early antituberculosis treatment.


Annals of Family Medicine | 2018

The Influence of Family Physicians Within the South African District Health System: A Cross-Sectional Study

Klaus B. von Pressentin; Robert Mash; Laurel Baldwin-Ragaven; Roelf Petrus Gerhardus Botha; Indiran Govender; Wilhelm Johannes Steinberg; Tonya M. Esterhuizen

PURPOSE Evidence of the influence of family physicians on health care is required to assist managers and policy makers with human resource planning in Africa. The international argument for family physicians derives mainly from research in high-income countries, so this study aimed to evaluate the influence of family physicians on the South African district health system. METHODS We conducted a cross-sectional observational study in 7 South African provinces, comparing 15 district hospitals and 15 community health centers (primary care facilities) with family physicians and the same numbers without family physicians. Facilities with and without family physicians were matched on factors such as province, setting, and size. RESULTS Among district hospitals, those with family physicians generally scored better on indicators of health system performance and clinical processes, and they had significantly fewer modifiable factors associated with pediatric mortality (mean, 2.2 vs 4.7, P =.049). In contrast, among community health centers, those with family physicians generally scored more poorly on indicators of health system performance and clinical processes, with significantly poorer mean scores for continuity of care (2.79 vs 3.03; P =.03) and coordination of care (3.05 vs 3.51; P =.02). CONCLUSIONS In this study, having family physicians on staff was associated with better indicators of performance and processes in district hospitals but not in community health centers. The latter was surprising and is inconsistent with the global literature, suggesting that further research is needed on the influence of family physicians at the primary care level.


Vaccine | 2017

A cross sectional survey to evaluate knowledge, attitudes and practices regarding seasonal influenza and influenza vaccination among diabetics in Pretoria, South Africa

Olawale D. Olatunbosun; Tonya M. Esterhuizen; Charles Shey Wiysonge

BACKGROUND In South Africa, influenza vaccination is recommended to all diabetics. However, vaccination coverage among diabetics remains low. Therefore, this study aimed to explore the knowledge, attitudes, and practices among people with diabetes in Pretoria regarding seasonal influenza and influenza vaccination. METHOD A cross-sectional survey was conducted among type 1 and 2 diabetes mellitus patients who attended diabetic clinics in two major tertiary hospitals in Pretoria, South Africa from October to December 2015. The pilot-tested questionnaire consists of 32 quantitative questions that covered seasonal influenza and influenza vaccination in terms of the patients demographics, medical history and knowledge, attitudes and practices. RESULTS A total of 292 completed questionnaires were received with a response rate of 70.0%. Of these, 162 participants (55.5%) believed that influenza is the same as common cold. While 96 (32.9%) participants were aware that they were at higher risk of complications of influenza, only 86 (29.5%) participants considered vaccination as an effective means in preventing serious influenza-related complication. Even though 167 (57.2%) participants had heard of the vaccine to prevent influenza, only 84 (28.8%) participants were previously vaccinated. Multivariate analysis shows that participants with good attitude score for influenza vaccination were 18.4 times more likely to be vaccinated compared with those with poor attitude score (OR =18.4, 95%CI. 5.28-64.10, p = .001). Among those previously vaccinated, advice from their doctors (82/84, 97.6%) was the main factor encouraging vaccination. Top reasons given by participants who had never been vaccinated before (208/292, 71.2%) include use of alternative protection (107/208, 51.4%) and that vaccination is not necessary because flu is just a minor illness (93/208, 44.7%). CONCLUSION Uptake of seasonal vaccination among diabetics in Pretoria is low. Level of knowledge and perception are the main barriers to vaccination. Health care providers advice may be an important key predictor of previous influenza vaccination and they should continue to educate and encourage all diabetics to get vaccinated for influenza at least once yearly.

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David Meyer

Stellenbosch University

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Ayesha A. Motala

University of KwaZulu-Natal

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Jimmy Volmink

South African Medical Research Council

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Robert Mash

Stellenbosch University

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Taryn Young

Stellenbosch University

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