Is a targeted and planned GP intervention effective in cardiovascular disease prevention? A randomized controlled trial

Background

Because cardiovascular diseases (CVD) are still the leading cause of mortality in the world, the World Health Organization in 2011 agreed to take concerted action to reduce mortality from CVD by 25% by 2025 [1]. Primary and secondary prevention of CVD is a high priority, and it is reflected in current guidelines of many national societies such as the European Society of Cardiology (ESC) and the National Institute for Health and Care Excellence [2,3]. Optimal screening strategies for identifying patients at high risk for developing CVD have been studied extensively and various sorts of interventions have been undertaken [4]. Assessment of CVD risk is a key to efficient cardiovascular prevention. It is important that individuals at risk of developing CVD can be effectively identified and appropriately stratified. The ESC recommended the Systematic Coronary Risk Evaluation (SCORE) chart for the total cardiovascular (CV) risk assessment. Change in lifestyle habits is recommended to all patients except to those with low CV risk, and pharmacotherapy is recommended to patients with high and very high CV risk [2].

The evidence shows that general practitioners (GPs) are the key persons to initiate, coordinate, and provide long-term follow-up for CVD prevention because in most countries they take care of >90% of the population [2]. The strength of general practice is its accessibility to the population. It has been proven that in most European countries, more than 60% of the population consults their GP at least once a year [5]. According to ESC guidelines, a GP should assess the total CV risk for every adult man ≥40, and woman ≥50 years of age or the post-menopausal [2]. There are multiple barriers to the implementation of risk-adjusted prevention in a general practice setting, especially the fact that prevention is time-consuming [6]. The use of risk scoring based on an electronic patient record is promising [7]. In Croatia, where this study was conducted, all GPs had been electronically recording patient data with an integrated total CV risk calculator since 2005. Systematized and precisely planned intervention by a GP leads to a reduction of total CV risk. Considering single risk factors included in the charts for total CV risk assessment, the best outcome has been achieved in the regulation of dyslipidemia and hypertension. The aim of this study was to evaluate the impact of GP’s systematic and planned intervention on total cardiovascular risk reduction and change in individual CV risk factors.

Material and Methods

STUDY DESIGN:

The study was conducted as part of the Cardiovascular Risk and Intervention Study in Croatia – family medicine (CRISIC-fm). It was a multicentric, randomized, prospective, cohort and intervention study, conducted in 2 phases (cross-sectional and intervention) and registered as clinical research (International Standard Randomized Controlled Trial Number Register – ISRCTN31857696). Sixty-four GPs from all over Croatia participated in the study and every GP included up to 55 patients aged ≥40, who had visited their office for any reasons from May to July 2008 and signed the informed consent to participate. The representative sample of GP offices was selected by the 4-stage stratification method: district (21 districts), region (coastal and continental), town size (up to 3999 inhabitants, 4000–9999, 10 000–29 999, 30 000–89 999, and 90 000 inhabitants and more) and the number of insured subjects contracted between GPs and the Croatian Institute for Health Insurance in 2007 (national compulsory health insurance system covering 97% of the population). General practitioners (N=64) and patients were randomly allocated to usual care as a control group (N=32) and to an active and planned intervention group (N=32). The sample size of 55 participants included by each GP was obtained by the statistical power analysis (minimum 80% with 95% confidence interval [CI]). Exclusion criteria were the inability to communicate (e.g., dysphasia and aphasia), dementia, and expected survival under 6 months. All examinees were prospectively followed up. At 18 months after the first visit, they filled in a questionnaire identical to the one used at the beginning of the study, including anthropometric measurements and blood analyses. The study was approved by the Ethics Committee of the Medical Faculty in Zagreb.

QUESTIONNAIRE:

We used the CRISIC-fm, which is a standardized, validated questionnaire with 140 questions, designed for the study, including socio-demographic, socio-economic, personal and family history data, psychological determinants, data about the diet and lifestyle habits, physical activity, and pharmacological therapy of the participants.

GUIDELINES:

We used the SCORE chart from 2012 for total CV risk assessment to group the examinees aged 40–69. The SCORE system estimates the 10-year risk of the first fatal atherosclerotic event by considering the effect of the major factors: age, sex, smoking, systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol. Subjects with a SCORE <1% were categorized as low risk, those with a SCORE was ≥1% and <5% were categorized as moderate risk, and all those with a calculated SCORE ≥5% and <10% were categorized as high risk. Participants who at the time of study had CVD, diabetes, or chronic kidney disease (CKD), or had a SCORE ≥10% were considered as very high-risk subjects. CVD was defined as previous myocardial infarction, acute coronary syndrome, coronary and other arterial revascularization, ischemic stroke, angina pectoris, and peripheral arterial disease. Moderate-to-severe CKD was considered as glomerular filtration rate <60/ml/min/1.73 m2 [2]. All participants who smoked or had stopped smoking within a year before the beginning of the study were considered to be smokers. Blood pressure was measured (arithmetic mean of 2 measurements with a mercury sphygmomanometer), and a fasting blood sample for the analysis of total cholesterol concentration, HDL and LDL cholesterol, triglycerides, glucose, and creatinine was taken from each participant. Target values of blood pressure were ≤140/90 mmHg in examinees with low or moderate risk and ≤130/80 mmHg in examinees with high or very high risk. Target values of total cholesterol in patients at low and moderate CV risk were considered to be ≤5.0mmol/L, HDL-cholesterol ≥1.03mmol/L for men and ≥1.29mmol/L for women, and those of LDL-cholesterol ≤3.0 mmol/L. Target values of total cholesterol in patients at high and very high total CV risk were considered to be ≤4.0mmol/L, and of LDL-cholesterol ≤2.5 mmol/L. Target value of triglycerides in all examinees was ≤1.7 mmol/L, body mass index (BMI) 20–24.99 kg/m2, and waist circumference ≤90 cm for men and ≤80 cm for women [8].

INTERVENTION GROUP:

Treatment of examinees in the intervention group was based on the ESC guidelines for the CVD prevention from 2007, which were adopted by the Croatian Cardiac Society [8]. GPs in the intervention group received printed educational materials, with precise and standardized protocols for counselling on healthy life style habits and pharmacotherapy, as well as tables for following up the examinees (at 1, 3, 6, 12, and 18 months) and educational leaflets for the examinees. GPs drafted individual personal plans with precise goals to correct the CV risk factors for each examinee in the intervention group that could be achieved in a given period. GPs in the intervention group participated in 2 repeated case-based training during a 6-month period.

CONTROL GROUP:

GPs in the control group received general information about the study and instructions about filling in the questionnaires, and they followed up and provided their examinees with the same standard care they had applied in the treatment of such patients before. GPs in the control group did not have printed educational materials and tables to follow up the patients, nor did they have educational leaflets for the examinees and additional organized workshops.

STATISTICAL ANALYSES:

Pre-study power calculation indicated that a trial with 64 GPs each including up to 55 patients had a power of 80% to detect a difference between the intervention and control group. The GP population in this study was very similar with respect to age, sex, and education. Multifactor analysis of variance (ANOVA) was used to detect differences before and after the intervention in intervention and control groups by assessing differences between repeated measurements (total CV risk according to SCORE chart, blood pressure, total cholesterol, HDL and LDL cholesterol, and triglycerides). Differences between the values of nominal variables (smoking) before and after the intervention were tested by McNemar’s dependent test. Test results for both groups (the intervention and the control) were calculated for each variable and the conclusion on the efficacy of GP’s intervention was inferred on the basis of the pattern of results. All obtained values were interpreted according to their level of significance of 95% (CI 95%, p<0.05). The SAS U statistical program was used for data processing (licence of Ministry of Science, Education, and Sport).

Results

Out of 1957 examinees included at the beginning (N=59 GPs), 1497 examinees aged 40–69 years completed this study (N=51 GPs), giving a response rate of 76.5% (Figure 1.).

At the beginning of this study, out of the total number of examinees (N=1957), 25.9% were at low, 40.2% were at moderate, 18.6% were at high, and 15.5% were at very high risk of fatal CVD according to the SCORE chart. Examinees at low risk were more often female and aged 40–49, unlike examinees at high and very high risk, who were more often male and older. Most of the patients with hypertension, elevated values of total and LDL cholesterol, lower values of HDL cholesterol, and smokers were at moderate risk for fatal CVD (Table 1).

At the beginning of the study, the intervention and the control group had almost identical distribution of total CV risk, sex, hypertension, elevated values of total cholesterol, lower values of HDL cholesterol, smokers, those who abused alcohol, and those who were physically active, while the participation of subjects with elevated values of LDL cholesterol was slightly higher in the intervention group (Table 2).

After 18 months, the study was completed with 1497 examinees aged 40–69, with 832 (55.6%) in the intervention group and 665 (44.4%) in the control group. regarding the total CV risk, 15.0% of examinees were at low, 41.1% at moderate, 19.4% at high, and 24.5% at very high risk. We found a significant difference in the distribution of the total CV risk between the examinees in the intervention group and those in the control group at very high risk (P<0.001). Although there was an increase in the participation of examinees with very high risk in both test groups, it was significantly higher in the control group. Examinees at low and moderate risk were more represented in the intervention group, while the incidence of high risk examinees was equal in both groups. Regarding single risk factors, the intervention group was more successful in blood pressure regulation, hypercholesterolemia, reaching target values of LDL cholesterol, and reduced consumption of alcohol. Thus, the planned intervention did not prove efficient in reducing smoking, increasing physical activity, and reaching target values of HDL cholesterol (Table 3).

Significant differences in average values of the examined risk factors showed in blood pressure, triglycerides, BMI, and waist and hip circumference. Values of systolic and diastolic blood pressure, triglycerides, BMI, and waist and hip circumference at the end of the study were lower in the intervention group, while in the control group these values increased. Although at the end of the study, average values of total, HDL, and LDL cholesterol were lower in the intervention group, no significant difference was found compared to the control group (Table 4).

Discussion

STRENGTHS AND LIMITATIONS OF THE STUDY:

The strength of this study is that it shows the effectiveness of a well-educated GP’s systematized intervention. A potential weakness of the study is the absence of investigation into patients’ attitudes towards prevention activities.

This study shows that total CV risk was decreased by use of precisely defined periods of follow-up of subjects with increased total CV risk for fatal CVD, and application of professional associations’ guidelines, including the examinees’ changing lifestyle habits. However, there is still room for research on how to attain the full potential of prevention and how to motivate both the practitioner and the patient. The usual routine of a practitioner who, when assessing total CV risk for a patient, does not use the professional associations’ charts, followed by intervention that is not systematically planned, does not lead to reduced number of CVD patients, which is especially important in countries like Croatia.

Conclusions

GP’s systematic and planned intervention in the prevention of CVD, along with their permanent education, reduces the number of patients with increased total CV risk, which in turn leads to reduced CVD mortality. To motivate patients to change behavior risk factors, besides the GP, the whole society needs to be included via efforts such as media campaigns and pro-health legislation.