Author: Zinta Harrington
Harrington, Zinta, 2005 B Cell antigen D8/17 as a marker of susceptibility to rheumatic fever in Australians and The sharp end of the needle: Rheumatic fever prophylaxis and concepts of care for Yolngu patients A thesis in two parts, Flinders University, School of Medicine
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Aboriginal Australians have some of the world’s highest rates of rheumatic fever. Two approaches to reducing the burden of rheumatic fever are discussed in this thesis. The B cell antigen D8/17 has a strong association with rheumatic heart disease and may be a universal marker of inherited susceptibility to rheumatic fever. Identifying a population at increased risk of rheumatic fever provides an opportunity to focus primary prevention measures. In part one of the thesis I evaluate the accuracy of D8/17 as a marker of past rheumatic fever amongst Australians from the Northern Territory. D8/17 levels were measured and compared in patients with acute rheumatic fever, rheumatic heart disease or past rheumatic fever, first-degree relatives and healthy, unrelated controls. The mean percentage of B cells positive for D8/17 was 83.7%, 38.9%, 20.2% and 11.6% respectively. The difference between the groups was significant (p-value less than 0.0001). A receiver operator curve analysis indicated that 22.1% of B cells positive for D8/17 was the most accurate cut-off to distinguish patients with acute or past rheumatic fever from healthy subjects. These results indicated that the B cell antigen D8/17 is an accurate marker of past rheumatic fever in Aboriginal Australians and could be a helpful addition to the Jones Criteria for strengthening or excluding a diagnosis of acute rheumatic fever. The intermediate levels of D8/17 expression in the relatives of index cases supports the hypothesis that D8/17 is a marker of an inherited susceptibility to rheumatic fever, although prospective trials are required to provide conclusive proof of this hypothesis. Non-compliance with secondary prophylaxis was suspected to be the cause of increasing rates of rheumatic fever in the Top End. In part two of the thesis I discuss the ‘problem of compliance’ with respect to Aboriginal patients, and investigate the factors that affected the delivery and uptake of prophylaxis for rheumatic fever in an Aboriginal community. Patients, relatives and health practitioners were interviewed on the topic of the care of patients with rheumatic heart disease. The data were analysed using the principles of grounded theory. The main finding was the desire for more personalised care and support for patients with rheumatic heart disease from the community clinic, rather than simple medical care. These ideas crystallised through two Yolngu terms to describe care: djaka (to physically care for) and gungayun (to encourage). Thus even from the outset there was divergence in the focus of the ‘consumer’- holistic care - and that of the health-care professional/ researcher – improving the rate of secondary prophylaxis coverage. With regards to service provision, a significant reason for failure to receive secondary prophylaxis was the differing approaches of urban and community health services, patient mobility, and a differing understanding of the responsibilities of patients and health service providers in the different settings. Other factors pertaining to service provision, such as staff motivation, administrative issues and program coordination affected the uptake of secondary prophylaxis to a lesser extent. With regards to treatment uptake, individual patient factors inhibiting uptake of treatment were apparent in some cases, but treatment refusal was rare. Pain was not found to be a deterrent. No simple relationship was found between treatment compliance and biomedical knowledge of the disease. There was no simple relationship between patient passivity and sense of responsibility that guaranteed compliance. This study demonstrated that the failure to achieve good uptake of prophylaxis for rheumatic fever related as much to factors of service provision as patient factors and that providing holistic care within a familiar and supportive framework is important to Yolngu patients. However, there are real difficulties for health services as they are currently structured to meet the expectations of patients and families.
Subject: Health Sciences thesis
Thesis type: Masters
School: School of Medicine
Supervisor: Professor Bart Currie