3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item The socio-economic impact on health behaviour regarding blood pressure management amongst young adults(2024) Mhlaba, MimiHypertension (HTN) is a leading cause of cardiovascular disease (CVD), with hypertension prevalence among young adults (YAs) increasing on a global as well as local scale. In South Africa between 1998 and 2016, Hypertension (HTN) rates in YAs (age 15-34 years) have more than doubled. Research reports that the increasing prevalence of HTN in YAs is largely attributed to unhealthy behaviours, such as unhealthy diet, physical inactivity, smoking, drinking alcohol, and poor sleep, with YAs also perceiving themselves as invulnerable to developing HTN at a young age. Formative research has shown that lack of education, employment, and training (NEET status) presents a significant barrier to healthier behaviours in YAs. Currently, 44.7% of South African youth are NEET, indicating the increased risk of pro-HTN behaviour in this group and the need for urgent intervention. While many learnerships addressing NEET rates in the country have been implemented, few are focused on health. Therefore, this study aimed to investigate if transitioning from a NEET status to employment and health education training changes perceptions of HTN risk and health behaviour intentions. METHODS We conducted six focus group discussions (FGDs) comparing HTN-related beliefs and intention for behaviour change between NEET youth (n=20; not in employment, education, or training) and previously NEET youth on a health employment and education training initiative (HETI); n=20). All FGDs were approximately 70 minutes in duration and were recorded and transcribed verbatim. The study utilised the conceptual framework of the Health Belief Model (HBM) to inform the FGD topic guide and a deductive thematic analysis. Frequent debriefing and review sessions with research supervisors were conducted to ensure the quality of the analysis. RESULTS All youth were familiar with HTN but for NEET youth, who only knew it as “high-high” or “high blood”, this was mostly through experiences of others in their social network. While all youth viewed HTN as life-threatening if left untreated and expressed fear of lifelong medication use if diagnosed, only HETI youth felt empowered to implement positive health behaviours for disease prevention. Intention for behaviour change was related to personal relevance resulting from the practical application of HTN knowledge in their daily lives. In contrast, NEET youth felt chronic disease was inevitable at an older age and demonstrated no intention for behaviour change. Past negative experiences in local clinics and the fear of distress in the event of a possible diagnosis were described as major deterrents to blood pressure (BP) screening. CONCLUSION Results suggest that engaging NEET (Not in employment, education, or training) youth in similar HETI (Health employment and education training initiative) programs can increase personal relevance of health information, which serves as a motivator to increase intentions toward healthier behaviours for chronic disease prevention. This may also result in double-duty benefits, reducing a NEET status as well as the risk for chronic illness among the YA population.Item The prevalence and predictors of HIV-hypertension comorbidity among youth living with HIV in South Africa, 2010-2016(2018) Makuapane, Lerato PatriciaOver the last two decades, AIDS mortality rates has decreased substantially due to extensive HIV treatment in South Africa, which left HIV as a chronic illness. Therefore, since the disease nature of HIV predisposes patients to other clinical conditions; many HIV patients also suffers from other AIDS-related and non-AIDS diseases resulting in comorbidities. It is most prevalent among population aged 14-35 years. At the same time, NCDs are rapidly increasing among youth with hypertension being amongst the leading cause of HIV comorbidities. High prevalence of both HIV/ AIDS and hypertension in this cohort rise a concern of their simultaneous occurrence to develop HIV-hypertension comorbidity. Abbreviation abstract)Item Central aortic pressure waveforms in hypertension(2019) Tade, Oluwatosin GraceThe impact of hypertension on cardiovascular end organs is mediated by increases in steady-state and pulsatile components of blood pressure (BP). The pulsatile component of BP is determined by both a forward travelling pressure wave produced by ventricular ejection and a backward pressure wave generated by wave reflection off points of vascular tapering. Although the backward pressure wave contributes to events, the factors that influence the impact and the most appropriate method of measuring the adverse effects thereof are unclear. In the present thesis I explored several aspects of the determinants, impact and measurement of backward travelling pressure waves. An extended time of the forward pressure wave and increased speed of wave travel with an earlier return of the backward wave enhance overlap of these waves and hence augment pulse pressure (PP). The extent to which these factors influence the impact of backward wave pressures on end organ is nevertheless unknown. In 701 participants randomly selected from a community sample of African descent, I demonstrated that neither the time to the peak of the forward wave nor the speed of wave reflection were independently associated with echocardiographic left ventricular mass (LVM). However, there was a strong interaction between the time to the peak of the forward wave and central aortic PP (PPc) or peak backward wave pressure (Pb) to determine LVM and LV hypertrophy. Thus, the time to the peak of the forward pressure wave is a major determinant of the impact of backward wave pressures and hence PPc on LVMI. Augmentation of PPc (augmentation index [AIx]) is increased in women as compared to men. However, the contribution of the peak of the forward wave pressure (Pf) and Pb to the increases in AIx in women is uncertain. In some populations, Pf contributes more than Pb to the increases in AIx in women, but the role of Pf or Pb in determining sex differences in AIx in populations where Pb plays a major role in explaining variations in PPc, is unknown. In 1097 participants randomly selected from a community sample of African descent, I showed that as compared to men, women have an increased AIx. The most important change associated with sex differences in AIx was an increased reflected wave magnitude (RM=PPb/Pf x 100). Thus, in groups of African ancestry an increased wave reflection rather than forward wave pressures largely accounts for sex differences in AIx. The β-adrenergic receptor blocker, atenolol, is not as effective as alternative antihypertensive agents at preventing cardiovascular events, an action attributed to increases in AIx. However, whether this is a class effect of all β-adrenergic receptor blockers or an effect of atenolol on wave reflection is uncertain. In the present thesis, using simultaneous carotid pressure and aortic outlet tract velocity and diameter assessments and subsequently performing wave separation analysis, I showed that across a range of steady-state pressures (induced by phenylephrine administration), atenolol given to spontaneously hypertensive rats for 3 months resulted in increases in AIx associated with an increased time to peak Pf and an enhanced RM. Thus the deleterious effect of atenolol on AIx is attributed to both a class effect (heart rate-dependent increases in the time to peak Pf) as well as an effect specific to the vascular effects of atenolol on wave reflection. Although aortic backward wave function (RM and Pb) predicts events, the assessment requires wave separation analysis. Whilst AIx has been employed as an easy and reproducible approach to reflected wave function, it underestimates backward wave effects. In this present thesis, in 1367 participants from a community sample I assessed whether the second systolic shoulder of the peripheral pulse waveform [pP2]) more accurately indexes Pb effects than aortic pressure augmentation (Pa). Importantly, pP2 was more closely correlated with Pb than Pa. The largest difference was at the highest tertile of the reflected wave foot time, where the speed of wave reflection was lowest. Consequently, independent of brachial BP and additional confounders, Pb or pP2 but not Pa were independently associated with LVM. Thus, pP2 which is readily identified on a peripheral pulse wave, may be a useful surrogate of Pb effects. In conclusion, in the present thesis I show that an extended time to the peak of the forward wave pressure determines the impact of backward wave pressures on LVM; that atenolol-based antihypertensive therapy not only produced adverse effects on aortic function by extending the time to the peak of the forward wave through heart rate-related effects (class effect), but also increases wave reflection (specific to non-vasodilator β-adrenergic receptor blockers); that the adverse effects of female gender on aortic function in groups of African ancestry are through enhanced backward pressure waves and that backward wave pressure effects, although inadequately indexed by aortic augmented pressure, can be appropriately indexed by the second systolic shoulder of the peripheral pulse. These data provide further insights into the adverse effects and appropriate measures of central arterial wave reflection.Item Burden of treatment and blood pressure control of patients with hypertension at a primary care facility, Sedibeng District, Gauteng Province(2018) Pender, KevinBurden of treatment (BOT) refers to the tasks patients, must perform in order to achieve optimal outcomes in their disease management. Hypertension is the commonest chronic disease of lifestyle, and previous studies have shown its control is suboptimal in most settings. Although studies conducted elsewhere have associated poor blood pressure (BP) control with high BOT, it is not known whether this holds true in South Africa, yet this information is important for a comprehensive management approach to hypertension. Previous studies in Sedibeng district have illustrated prevalent poor blood pressure control, however local studies providing understanding of how this relates to BOT are lacking. Objectives: 1. To assess BOT among patients with hypertension at Johan Heyns Community Health Centre (CHC). 2. To determine the proportion of participants with BP controlled to target. 3. To explore the relationship between BOT and BP control. Methods: This was a cross sectional study involving patients at Johan Heyns CHC with hypertension who have been on treatment for a minimum of three months. A treatment burden questionnaire (chronbach alpha 0.89) was administered to participants to collect information on burden of treatment relating to: Medication regimen Navigating the healthcare system. Life style changes, social and financial impacts. In addition, information on participants’ socio-demography and BP readings in the last three months were extracted from medical records. Data was entered into Epi info statistical software, and analysis included descriptive and association tests. Main outcome measures included: Proportion of participants with BP controlled to target, mean total BOT and the association between BOT and blood pressure control. Results: Of 239 participants, most were white (54.2%), female (60.1%), had completed matric or further education (71.9%), married (56.3%), older than 55 years (52.9%) and did not have clinical co-morbidities (56.7%). The mean duration of treatment was 113.8 months, with white people and female participants significantly more likely to have longer duration of treatment (p=0.03 and p=0.04 respectively). Most participants had uncontrolled BP (60.1%), with a mean BP of 143.7/87.2mmHg. Being divorced or african was associated with higher mean systolic BP (p=0.00 and p= 0.012 respectively); being single or male was associated with higher mean diastolic BP (p=0.00 and p=0.03 respectively). The mean total BOT score was 19.7(out of possible 140). Most participants (75%; n=177) reported a low mean BOT score (<47). In the three sub-aggregates of burdens (medication regimen, navigating the health system and lifestyle/social and financial), only 28.4% (n=67) and 15.7% (n=37) reported moderate to high BOT in the components of lifestyle modification/social support and navigating the health system respectively. Among those with clinical comorbidity (n=103), most (66.3%) did not consider hypertension to be more burdensome than the other comorbid illnesses. Single participants were significantly more likely to have a higher mean BOT score (p= 0.00). Although total BOT was not significantly associated with BP control (p=0.53), participants with a higher BOT related to medication regimen were significantly more likely to have an uncontrolled BP (p= 0.04). Conclusion: This study found that patients with hypertension reported low BOT despite most having poorly controlled BP. Considering only a minority reported moderate to high score in the three components of BOT, other elements in the process of care, such as poor healthcare providers’ adherence to guidelines and inertia in intensifying treatment, as well as poor patient compliance to treatment may be responsible for the prevalent poor BP control in the research setting.Item Knowledge and lifestyle practices of hypertensive patients utilizing public and private health sectors in Umlazi Township of KwaZulu-Natal(2018) Simamane, Mandis JewelBackground:The South African government has taken several measures to address the evolving epidemic of non-communicable diseases (NCDs), but so far these efforts have not been effective in preventing the rising burden from these diseases. Hypertension is the most prevalent NCDs in society but unfortunately the control of this disease is suboptimal, and it is a growing health concern in all regions of the world, regardless of income. There is a substantial difference in resource availability between public and private health care sector (HCS) facilities and this result in disturbing impact on the population’s health, resulting in unnecessary morbidity and mortality. Understanding the patient’s knowledge, management of hypertension and its risk factors will help to identify the differences between the patients utilizing public and private health care (HC) providers in managing hypertension. Aims: To determine patient’s knowledge, management of hypertension and its risk factors between the patients utilizing public and private HC providers in managing hypertension. Methods: A cross-sectional study design was conducted in Umlazi Townships in KwaZulu-Natal (KZN); patient’s utilizing strictly public health sectors were compared to those strictly using the private health sectors. Measurements of blood pressure (BP), body mass index, waist-to-hip ratio, as well as hypertensive patients questionnaire, global physical activity question, diet and smoking questionnaire were used as measuring tools and instruments. For normally, distributed continuous data an independent two-tailed t test was used to determine any significant differences (p=≤0.05) and for non-normally distributed or categorical data a chi-square test was used. Results: A total of 137 people consented to participate in this study, comparison of the demographic characteristics was made between participants’ utilizing the public HCS (n=77) and private HCS (n=60). The participants average age was 65 years (±10.83) and 60 years (±9.15), for the public HCS and private HCS, respectively, the public HCS participants were significantly older than those attending private HCS (t=2.41) (p=0.02). The average BMI for the study sample (N=137) was 30.45kg·m2 on both the groups, classified as Obese I. No significance relationship (X2=0.03, p=0.85) was found between the type of HC provider and having been admitted to hospital over the last year, 58.44% and 58.33% participants felt their BP was better compared to 12 months ago, in the public and private HCS, respectively. A significance relationship (X2=3.96, p=0.05) was found between the type of HC provider the participants consulted for their hypertension and taking all prescribed medication, with public HCS (100%) participants being more likely to take their medication compared to the private HCS (95%). On average the participants global physical activity questionnaire total metabolic equivalents per week (t=0.63) (p=0.53) between the public and private HCS was 1803.12 (±4755.96) and 1385.33 (±2295.32), respectively. The public HCS (61.04% and 64.94%) had more participants that smoked regularly for ≥5 years (X2=5.98, p=0.02) and those that drank alcohol as compared to the private HCS (38.33% and 48.33%) (X2=3.81, p=0.05). Conclusion: The participants of the private HCS did not tend to have better knowledge and management of hypertension and its risk factors as compared to that of the public HCS, although there were few differences between the two groups. This suggests that an intervention programme, which invests in area based specific strategies, is recommended, including healthy lifestyle and physical activity, needs to be implemented in the community of Umlazi Township in managing hypertension.Item Prevalence and determinants of self-reported hypertension in urban poor settlements of Johannesburg(2017) Kinara, Fossa OgakeBackground: Hypertension is the leading risk factor for cardiovascular disease in Africa. Cardiovascular disease is rated as the number one cause of death in Africa. Previously, hypertension was known to predominantly affect the affluent population but recently the condition has been emerging even among the poorer population, rendering it a greater burden. In South Africa its prevalence level has significantly escalated, particularly in urban areas, with higher incidence among the poor. The prevalence of self-reported hypertension and its risk factors is not well documented in the urban impoverished settlements. Understanding determinants and the prevalence of self-reported hypertension in these areas will help develop improved awareness, prevention and control strategies. This study aimed to determine the prevalence and determinants of self-reported hypertension in five urban impoverished sites in Johannesburg, South Africa. Methods: Secondary data analysis was done on data from the HEAD study which involved a sample of households from five urban poor areas. Prevalence levels of self-reported hypertension were estimated within the study areas. Summary measures of the data were computed and presented in a descriptive table. Distribution of the potential risk factors by prevalence of self-reported hypertension was also done. Lastly, binary logistic regression was used to model the unadjusted and adjusted association between the identified risk factors and self-reported hypertension. iv Results: The prevalence of self-reported hypertension among households in the five urban impoverished sites was 20 percent (n=107). The independent predictors of hypertension were study area (Riverlea, Hillbrow), race, age, gender (0.25-0.49 and ≥0.75), work (0.5-0.74, and ≥0.75), monthly income (ZAR 1000-2000, 2001-5000, and >5000), presence of another non-communicable disease and socioeconomic status (middle). Results from the adjusted model showed that race, sex, age and presence of at least one other non-communicable disease are were significantly associated with self-reported hypertension Conclusion: The study’s findings strengthen the case that age, sex, race, and co-morbid non-communicable diseases are associated with self-reported hypertension. Interventions that target the urban poor population and that focus on increasing awareness and context specific risk reduction are recommended. Further, the association with these factors should be confirmed by carrying out a more robust population-based study to inform policyItem Cost analysis and comparison of two global cardiovascular risk scores in hypertensive patients at Mafikeng provincial hospital: a preliminary exploratory study(2018) Mbuilu, Jody PukutaA preliminary study was done where South African Hypertension guideline risk score was compare with the WHO Cardiovascular risk score (for Southern Africa). At Mafikeng Provincial hospital 130 hypertensive patients were assessed using both scoring algorithms. Ninety (69%) of the 130 patients were high risk. The WHO risk score was able to classify 84 (93%) of the high risk patients by SA risk calculator also as high risk and 36 (90%) of the 40 low risk patients also as low risk. The WHO risk calculator has a sensitivity of 93% and a specificity of 90% with 89% accuracy.Item Hypertension : Experimental and clinical pharmacological studies(1985-09-08) Leary, William, Peregrine, PepperrellThe publications forming this submission cover two broad fields. A series of papers deal with experimental hypertension ; possible roles for angiotensin and prostanoid substances in the pathogenesis of hypertension were investigated. The results indicated that the capacity of kidney to inactivate angiotensin II could be quite profoundly altered by inducing hypertension using the one and two-clip Goldblatt methods or by altering the sodium chloride content of the diet.Item Examining the relationships between socio-economic status and hypertension: an application of structural equation modelling(2017) Morgan, RaquelOver the years, epidemiological research has seen differing levels of the prevalence of hypertension across socio-economic strata. However in Sub-Saharan Africa, the patterns of association and underlying risk factors have often been poorly understood. In this study, we examined the extent to which socio-economic factors affect systolic and diastolic blood pressure across gender. Furthermore we explored whether certain risk factors associated with hypertension mediate this relationship. We used data from the third phase of the National Income Dynamic Study conducted in South Africa in 2012 on more than 18,000 adult individuals. Structural equation modelling and multiple linear regression were used to estimate the relationship between blood pressure and various behavioural, demographic and socio-economic variables. These results were then compared to determine which technique provides more meaningful results. A higher socio-economic status was associated with a higher systolic and diastolic blood pressure in both males and females. Furthermore, body mass index was a mediator of the indirect effect of socio-economic status on blood pressure. Smoker status, alcohol consumption, physical exercise, emotional well-being and resting heart rate were also mediators; however their role was modest in comparison to BMI. One of the findings of this study is that a reduction in the BMI of an individual will have an impact on lowering hypertension. Furthermore, the promotion of healthy behaviours that target higher income groups need to be established so that these groups can make rational decisions in choosing their behaviours.Item Patient-related factors associated with control of hypertension at Jabulani Dumane community health centre, Ekurhuleni district, Gauteng province(2017) Nyanga, MahambaINTRODUCTION: Jabulani Dumane Community Health Centre offers comprehensive care to hypertensive patients. Following the establishment of healthcare workers’ responsibilities in hypertension control by a quality improvement project, this study aimed to establish patient-related factors in hypertension control. A hypothesis understudy was done to affirm that the psychosocial characteristics and demographics of patients are among the most important contributors to the control of hypertension. It is believed that the findings of this study will provide healthcare workers with the information they need to counsel their patients. METHOD: This was a cross-sectional descriptive study. Patients were directly interviewed to obtain information about their demographics and psychosocial characteristics. Previous blood pressures were obtained directly from records. All information gathered was described and analysed. Association between each variable and control of hypertension was analysed. Statistical tests used were Chi-square and Fisher’s exact test. RESULTS: Results showed a statistically significant association between the following variables and hypertension control: marital status (p=0.002); adherence to medication (p=0.0060); adherence to physical exercises (p = 0.0029). CONCLUSION: Patient-related factors associated with control of hypertension included marital status, adherence to treatment, and physical exercise. Hypertension control can be enhanced by improving adherence to treatment and healthy lifestyle (physical exercise and diet).