Healthy Hearts Methodology

Dr Melinda Carrington, Professor Simon Stewart and Professor Garry Jennings

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Study setting and design

Healthy Hearts was a regional observational research study. In order to distribute limited resources to areas that required it most, we used Geographical Information System profiling 1 to identify regional cities with >20,000 total population in Victoria and which had an increased prevalence of chronic heart failure, Aboriginal and Torres Strait Islanders, obese children aged 7-18 years and adults over 65 years of age. Of 10 high risk communities identified, four relatively geographically dispersed were purposefully selected to visit (see Figure 1). These included Colac (adult population of 7,172 and 152 km South-West of Melbourne), East Gippsland (11,251 and 294 km North-East of Melbourne), Geelong (3,664 and 75 km South-West of Melbourne) and Shepparton (20,410 and 190 km North of Melbourne).

Co-ordination of the Healthy Hearts program was facilitated by the local Rotary Clubs in each community. The program was operational between 0830 and 1700 on all weekdays. We had the capacity for approximately 40 assessments per day, averaging five per hour or 12 minutes per participant. A combination of free heart health checks via a mobile risk assessment unit were undertaken in public settings such as a shop or park location (73% of all assessments) or via dedicated workplace visits to key businesses. Assessments were performed concurrently by a team of at least four Registered Nurses and fully trained research personnel according to a standardised protocol. The study was approved by the Human Research Ethics Committee at the Alfred Hospital, Melbourne, Australia (Project No. 71/07) and the STROBE guidelines were referred to in reporting studies of this nature 2.

- Healthy Hearts Methodology - figure 1

Figure 1. Map of Victoria highlighting the four communities visited as part of the Healthy Hearts program

Participants

We aimed to conduct at least 500 health checks over a continuous 3-4 weeks of screening per community in 2007-2010. Prior to our arrival, the program was advertised in the local newspaper(s) and radio station and key businesses were notified. Participants self-selected and the only inclusion criteria were to be over 18 years of age with the ability to provide written consent to participate. Overall, 2,125 participants from the four regional communities volunteered to have a risk assessment. The proportion of the adult population assessed (based on place of usual residence) was 8% in Colac, 5% in East Gippsland, 14% in Geelong and 3% in Shepparton 3.

Data Collection

The program comprised three stages; 1) self-report questionnaire, 2) non-invasive clinical assessment and, 3) absolute cardiovascular disease (CVD) risk assessment report and brief consultative review. The self-administered questionnaire incorporated validated assessment instruments and examined the following: socio-demographic indicators; diet and lifestyle habits such as smoking (current smoker, ex smoker or never smoked); fat intake using the MEDFICTS dietary assessment tool 4; physical activity via the International Physical Activity Questionnaire 5; personal and family medical history; medication use; mental health via the 2-item Arroll questionnaire 6 and CES-D 7; angina and intermittent claudication symptoms using the Rose Angina questionnaire 8; and overall health and well-being via the SF-12 9. Education was classified as either secondary school or below or higher than secondary school. Clinical assessments included measurement of blood pressure (BP), height, weight, anthropometric measurements of abdominal and hip circumference, point of care random lipid and glucose profiling, electrocardiography (ECG), spirometry, and in a sub-sample, the ankle brachial pressure index to identify peripheral arterial disease. The results from many of these variables will be the focus of a number of future publications. In the final part of participation, a summary report describing an individual's cardiovascular risk factor profile, 5-year (primary) 10, 11 or 2-year (secondary) 12 absolute CVD risk score and 5-year type 2 diabetes risk 13 was given to participants and the details were explained by a senior member of the Healthy Hearts team (MC, SS or senior cardiac nurse). During the feedback session, advice and education was given to address any risk factors; in the case of an extreme or adverse test result, participants were advised to consult their general practitioner (GP) for follow-up or were directed to hospital for more urgent cases.

Instrumentation and procedures

After 5 minutes of rest, BP in the brachial artery was measured using a validated digital BP monitor (Dinamap® PROCARE 300, GE Healthcare, Buckinghamshire, UK) 14 in the sitting position with an appropriately sized cuff and table support for the measured arm. The average of two measurements separated by a one-minute interval was analysed provided there were no large variations in systolic (≥10 mmHg) or diastolic (≥7 mmHg) BP, in which case another reading was taken and the closest two readings were analysed. Height and weight for assessing body mass index (BMI, kg/m2) were measured using a stadiometer and digital weighing scales, with the removal of shoes and heavy garments. Abdominal and hip circumference were measured in the horizontal plane whilst standing, in accord with the World Health Organization (WHO) STEPwise approach to surveillance (STEPS) procedure 15; the level mid-way between the lowest rib and iliac crest at the end of a gentle expiration was taken for abdominal circumference and the level at the maximum extension of the buttocks defined hip circumference. Lipid and glucose measurements were analysed by a validated Cholestech LDX® System (Cholestech Corporation, CA, USA) 16, 17. Portable PC-based 12-lead ECGs (Universal ECGTM) were collected in adherence with standard electrode placement using Office MedicTM Software (QRS Diagnostic, MN, USA). Absolute cardiovascular risk for primary prevention 11 was calculated using age, gender, smoking status, diabetes, systolic BP and total cholesterol (TC)/high density lipoprotein cholesterol (HDL-C) ratio, with an adjustment for extremely elevated TC, diastolic BP, kidney disease and type 2 diabetes 10. The variables for secondary prevention were age, gender, diabetes, TC, HDL-C and for women only, systolic BP and smoking status 12.

Risk factor definitions

Ideal individualised risk factor targets were based on national guidelines, reports and validated assessment tools. Those who currently smoked or had stopped smoking less than 12 months before the assessment were defined as a smoker. Energy intake from dietary saturated fat scores were classified as low (<40), moderate (40-69) or high (≥70) 4. Physical inactivity was defined as less than 150 minutes per week of activity 18, with vigorous intensity activity counted as double time and moderate intensity or brisk walking counted as single time 19. Excess alcohol consumption was defined as >2 drinks standard drinks on any day 20. Participants who answered yes to either of two screening questions for potential depression 6 proceeded to complete the CES-D whereby depression was indicated by a score of ≥16 7.

Hypertension was defined as BP ≥ 130/80 mmHg for participants with associated condition(s) or end organ damage, and for all others as BP ≥ 140/90 mmHg 21. Participants were classified by BMI as normal weight (< 25 kg/m2), overweight (25 - < 30 kg/m2) or obese (≥ 30 kg/m2) 22. Normal weight was classified by an abdominal circumference <94 cm for men and <80 cm for women, overweight for measurements between 94 to <101.9 cm (men) and 80 to <87.9 cm (women), and obese for measurements ≥102 cm for men and ≥88 cm for women 19. For higher risk participants taking lipid-modifying therapy, treatment target levels used were <4 mmol/L for TC, <2.0 mmol/L for low density lipoprotein cholesterol (LDL-C) and <1.5 mmol/L for triglycerides 23. The recommended target levels for all other participants not on lipid-modification treatment were 5.5 mmol/L for TC, 3.0 mmol/L for LDL-C and 2.0 mmol/L for triglycerides 19, 24. For all participants, the target level for HDL-C was 1.0 mmol/L 23 and <6.9 or <11.0 mmol/L for fasting and random glucose levels, respectively 25. Dyslipidaemia was defined as not meeting any one of the lipid target levels just described. Metabolic syndrome was defined by abdominal obesity in the presence of any of two, including treatment for, the following deficiencies: raised levels of triglycerides, BP, fasting glucose (where applicable) or reduced HDL-C 26. Absolute primary and secondary cardiovascular risk was classified as low (≤9%), moderate (10-15%) or high (≥16%), defaulting those with extremely elevated TC or BP, kidney disease, or type 2 diabetes at >60 years of age to high risk (primary prevention risk scores only) 10. All ECGs were systematically scored by a trained cardiac nurse using the Minnesota Code 27 and confirmed by SS.

Data Analyses

All study data were documented on standardised case report forms, scanned and verified before populating a dedicated database (Microsoft Access).

References

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