Cardiovascular disease prevention : putting guidelines into practice

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide. CVD primary prevention guidelines recommend a multifactorial risk assessment to identify high-risk patients that will benefit most from treatment. Assessment and management of CVD risk is predominantly conducted by general practitioners (GPs), who are required to collect risk factors, estimate absolute CVD risk and determine clinical management. Yet this approach is poorly implemented in clinical practice. Consequently, the opportunity to identify and intervene with high risk patients may be missed. An essential component for CVD risk assessment is referral to pathology services for cholesterol measurement. In Australia, GPs issue ≈2 million cholesterol referrals to pathology per year. However, far fewer patients receive subsequent estimation of absolute CVD risk and guideline-recommended care. Pathology services present an opportunity to provide systematic, high-quality absolute CVD risk assessment and reporting embedded within existing primary care pathways. The overall aims of this research were to determine: the feasibility of absolute CVD risk assessment and reporting via pathology services in Tasmania; GPs perspectives of such a service; and the agreement in high-risk classification between international CVD prevention guidelines. Study 1 (Chapter 2) is a feasibility study of absolute CVD risk assessment and reporting via pathology services in 300 patients attending for cholesterol measurement. Patients completed absolute CVD risk assessment via a computer-based app that delivered participant information and informed consent, a clinical questionnaire and blood pressure (BP) measurement. The app transferred risk factor data to the pathology laboratory, it was matched with the patient’s cholesterol result and absolute CVD risk calculated. Individual risk factors, absolute CVD risk score and category, and guideline-recommended treatment were added to the pathology report alongside the requested cholesterol result and sent to the referring GP. Study 1 found that absolute CVD risk assessment and reporting via pathology services was feasible, acceptable and may increase guideline-directed care in practice. Study 2 (Chapter 3) sought to determine the efficacy and acceptability of a standalone multimedia informed consent process, delivered via computer-based app, compared to the traditional paper-based approach. This study was embedded within the aforementioned feasibility study. Obtaining informed consent is a cornerstone requirement of ethical research conduct, however, the traditional approach is lengthy and requires dedicated staff oversight. Multimedia tools, including video and audio, may offer an effective alternative. Study 2 found that a standalone multimedia consent process was effective and acceptable for obtaining consent in a clinical research setting free from research staff. Study 3 (Chapter 4) was a qualitative study to explore current CVD prevention practice and GP attitudes to absolute CVD risk assessment and reporting via pathology services, including discussing an example pathology report with absolute CVD risk information. GPs participated in either a focus group (n=8) or one-to-one interviews (n=10). GPs highlighted several barriers to current CVD risk screening including only having an opportunistic approach to screening at the end of a consultation if time permitted, the need for several consultations for risk factor collection and misclassification of patients by clinical intuition rather than using absolute CVD risk. GPs stated that absolute CVD risk reported via pathology services could address these deficits and a high-risk result would prompt a dedicated CVD prevention consultation that would otherwise not occur. Study 4 (Chapter 5) was a mixed-methods analysis with the same GPs from study 3, but where additional information was sought to determine their attitudes and practice towards BP management in the context of absolute CVD risk. GPs raised concerns regarding accuracy of BP measurement performed at pathology services and its equivalence to clinical practice measurements. Despite being provided with high quality BP values and absolute CVD risk, GPs would repeat measurement to confirm BP. GPs generally focused on single risk factor management and treatment of BP rather than according to CVD prevention guidelines. These findings suggest that BP primacy may be an impediment to guideline-directed care. Further, that engagement and education with GPs on absolute CVD risk assessment and BP management is needed. Study 5 (Chapter 6) sought to determine the effect of blood collection (as required for cholesterol measurement) on BP and subsequent estimation of absolute CVD risk. Forty five participants had BP measured according to clinical guideline methods. Then on a separate visit, BP was measured immediately pre-, during- and post-blood collection. Absolute CVD risk scores were calculated using systolic BP from each measurement condition and compared. The main conclusion of this study was that absolute CVD risk scores were not significantly affected by using BP recorded at the time of blood collection. Therefore, both BP and blood collection may occur during the same consultation for absolute CVD risk assessment. Study 6 (Chapter 7) assessed agreement in high-risk classification between CVD prevention guidelines from Australia, England and the Unites States using nationally representative data. International CVD prevention guidelines vary in the prediction tools and threshold for therapy, the target population and clinical characteristics that denote high-risk, which may result in different therapeutic recommendations. There was little agreement in high-risk classification between international CVD prevention guidelines, due to both absolute CVD risk estimation and clinical criteria that denote high risk. These findings highlight the need to develop international consensus for CVD primary prevention guidelines. In summary, this research program provides valuable new information that interventions embedded within practice may address practice challenges and support guideline-directed care for CVD primary prevention. These findings could lead to real-world improvements in CVD preventive care and guideline development