Using thresholds based on risk of cardiovascular disease to target treatment for hypertension: modelling events averted and number treated

Geographic and Sociodemographic Disparities in Cardiovascular Risk in Burkina Faso: Findings from a Nationwide Cross-Sectional Survey

Background

Cardiovascular disease (CVD) risk assessment is a critical step in the current approach to the primary prevention of CVD, particularly in low-income countries such as Burkina Faso. In this study, we aimed to assess the geographic and sociodemographic disparities of the ten-year cardiovascular risk in Burkina Faso.

Methods

We conducted a secondary analysis of the data from the first nationwide survey using the World Health Organization (WHO) STEPwise approach. Ten-year cardiovascular risk was determined using the WHO 2019 updated risk chart (WHO risk) as main outcome, and the Framingham risk score (FRS) and the Globorisk chart for secondary outcomes. We performed a modified Poisson regression model using a generalized estimating equation to examine the association between CVD risk and sociodemographic characteristics.

Results

A total of 3081 participants aged 30 to 64 years were included in this analysis. The overall age and sex-standardized mean of absolute ten-year cardiovascular risk assessed using the WHO risk chart was 2.5% (95% CI: 2.4–2.6), ranging from 2.3% (95% CI: 2.2–2.4) in Centre Est to 3.0% (95% CI: 2.8–3.2) in the Centre region. It was 4.6% (95% CI: 4.4–4.8) for FRS and 4.0% (95% CI: 3.8–4.1) for Globorisk. Regarding categorized CVD risk (absolute risk ≥10%), we found out that the age and sex-standardized prevalence of elevated risk was 1.7% (95% CI: 1.3–2.1) for WHO risk, 10.4% (95% CI: 9.6–11.2) for FRS, and 5.9% (95% CI: 5.1–6.6) for Globorisk. For all of the three risk scores, elevated CVD risk was associated with increasing age, men, higher education, urban residence, and health region (Centre).

Conclusion

We found sociodemographic and geographic inequalities in the ten-year CVD risk in Burkina Faso regardless of risk score used. Therefore, population-wide interventions are needed to improve detection and management of adult in the higher CVD risk groups in Burkina Faso.

Eligibility and subsequent burden of cardiovascular disease of four strategies for blood pressure-lowering treatment: a retrospective cohort study

BACKGROUND

Worldwide treatment recommendations for lowering blood pressure continue to be guided predominantly by blood pressure thresholds, despite strong evidence that the benefits of blood pressure reduction are observed in patients across the blood pressure spectrum. In this study, we aimed to investigate the implications of alternative strategies for offering blood pressure treatment, using the UK as an illustrative example.

METHODS

We did a retrospective cohort study in primary care patients aged 30-79 years without cardiovascular disease, using data from the UK's Clinical Practice Research Datalink linked to Hospital Episode Statistics and Office for National Statistics mortality. We assessed and compared four different strategies to determine eligibility for treatment: using 2011 UK National Institute for Health and Care Excellence (NICE) guideline, or proposed 2019 NICE guideline, or blood pressure alone (threshold ≥140/90 mm Hg), or predicted 10-year cardiovascular risk alone (QRISK2 score ≥10%). Patients were followed up until the earliest occurrence of a cardiovascular disease diagnosis, death, or end of follow-up period (March 31, 2016). For each strategy, we estimated the proportion of patients eligible for treatment and number of cardiovascular events that could be prevented with treatment. We then estimated eligibility and number of events that would occur during 10 years in the UK general population.

FINDINGS

Between Jan 1, 2011, and March 31, 2016, 1 222 670 patients in the cohort were followed up for a median of 4·3 years (IQR 2·5-5·2). 271 963 (22·2%) patients were eligible for treatment under the 2011 NICE guideline, 327 429 (26·8%) under the proposed 2019 NICE guideline, 481 859 (39·4%) on the basis of a blood pressure threshold of 140/90 mm Hg or higher, and 357 840 (29·3%) on the basis of a QRISK2 threshold of 10% or higher. During follow-up, 32 183 patients were diagnosed with cardiovascular disease (overall rate 7·1 per 1000 person-years, 95% CI 7·0-7·2). Cardiovascular event rates in patients eligible for each strategy were 15·2 per 1000 person-years (95% CI 15·0-15·5) under the 2011 NICE guideline, 14·9 (14·7-15·1) under the proposed 2019 NICE guideline, 11·4 (11·3-11·6) with blood pressure threshold alone, and 16·9 (16·7-17·1) with QRISK2 threshold alone. Scaled to the UK population, we estimated that 233 152 events would be avoided under the 2011 NICE guideline (28 patients needed to treat for 10 years to avoid one event), 270 233 under the 2019 NICE guideline (29 patients), 301 523 using a blood pressure threshold (38 patients), and 322 921 using QRISK2 threshold (27 patients).

INTERPRETATION

A cardiovascular risk-based strategy (QRISK2 ≥10%) could prevent over a third more cardiovascular disease events than the 2011 NICE guideline and a fifth more than the 2019 NICE guideline, with similar efficiency regarding number treated per event avoided.

FUNDING

National Institute for Health Research.

Cardiovascular disease risk and comparison of different strategies for blood pressure management in rural India

BACKGROUND

Non-optimal blood pressure (BP) levels are a major cause of disease burden globally. We describe current BP and treatment patterns in rural India and compare different approaches to BP lowering in this setting.

METHODS

All individuals aged ≥40 years from 54 villages in a South Indian district were invited and 62,194 individuals (84%) participated in a cross-sectional study. Individual 10-year absolute cardiovascular disease (CVD) risk was estimated using WHO/ISH charts. Using known effects of treatment, proportions of events that would be averted under different paradigms of BP lowering therapy were estimated.

RESULTS

After imputation of pre-treatment BP levels for participants on existing treatment, 76·9% (95% confidence interval, 75.7-78.0%), 5·3% (4.9-5.6%), and 17·8% (16.9-18.8%) of individuals had a 10-year CVD risk defined as low (< 20%), intermediate (20-29%), and high (≥30%, established CVD, or BP > 160/100 mmHg), respectively. Compared to the 19.6% (18.4-20.9%) of adults treated with current practice, a slightly higher or similar proportion would be treated using an intermediate (23·2% (22.0-24.3%)) or high (17·9% (16.9-18.8%) risk threshold for instituting BP lowering therapy and this would avert 87·2% (85.8-88.5%) and 62·7% (60.7-64.6%) more CVD events over ten years, respectively. These strategies were highly cost-effective relative to the current practice.

CONCLUSION

In a rural Indian community, a substantial proportion of the population has elevated CVD risk. The more efficient and cost-effective clinical approach to BP lowering is to base treatment decisions on an estimate of an individual's short-term absolute CVD risk rather than with BP based strategy.

CLINICAL TRIAL REGISTRATION

Clinical Trials Registry of India CTRI/2013/06/003753 , 14 June 2013.

Misleading Measurements: Modeling the Effects of Blood Pressure Misclassification in a United States Population

Objective. The clinical diagnosis of hypertension is subject to misclassification, and this may be clinically important. This article calculates positive and negative predictive values for blood pressure measurement and assesses the frequency of clinically important blood pressure misclassification. Design, Setting, and Participants. A modeling study was carried out on 4763 adults in the National Health and Nutrition Examination Survey (NHANES) population. True treatment eligibility was determined by applying Joint National Committee (JNC) VII criteria to individuals in the study population. Each individual was also allocated a series of blood pressures incorporating an error term reflecting day-to-day measurement variation. Test positives are persons classified as needing treatment on the basis of the mean of 2 blood pressure measurements. Measurements and Main Results. Positive predictive values of a diagnosis of hypertension based on 2 measurements were calculated for each age-sex group. Low-risk false positives and highrisk false negatives were categorized as clinically important errors. Positive predictive values are high in persons older than age 65. In persons ages 16 to 34, the positive predictive value is 0.24 (95% confidence interval [CI]: 0.17–0.32) in men and 0.16 (95% CI: 0.06–0.26) in women. Persons younger than age 35 are almost always at low risk of cardiovascular disease, and therefore this misclassification is clinically important. Even with 24-hour ambulatory blood pressure measurement, positive predictive values in young adults are under 0.5. Conclusions. Blood pressure estimation is a poor diagnostic test in low-prevalence populations such as young adults. Estimation of blood pressure should be informed by prior estimation of cardiovascular risk.

Evaluation of a systematic cardiovascular disease risk reduction strategy in primary healthcare: an exploratory study from Zhejiang, China

BACKGROUND

In China, cardiovascular disease (CVD) risk reduction strategies are not systematically implemented in primary healthcare (PHC). We conducted an exploratory study to evaluate the preliminary effectiveness of our systematic CVD risk reduction package in one township hospital of Zhejiang.

METHODS

Using the Asian Equation, we selected subjects aged 40-74 years with a calculated 10-year CVD risk of 20% or higher from the existing resident health records and research checkup. The subjects were provided, as appropriate, with the low-dose combination of CVD-preventive drugs (antihypertensive drugs, aspirin, statin), lifestyle modification and adherence strategies monthly. The intervention was piloted for three months in 2012, preceding the conduct of a cluster-based randomized controlled trial (RCT).

RESULTS

A total of 153 (40%) subjects were recruited, with an average total 10-year risk of CVD of 28.5 ± 7.9%. After intervention, the appointment rate was up to 90%. An upward trend was observed for the use of CVD-preventive drugs. The smoking rates significantly reduced from 38 to 35%, with almost no change for salt reduction. The systolic blood pressure (BP) and diastolic BP decreased slightly.

CONCLUSION

A holistic CVD risk reduction approach shows preliminary effects in a rural PHC setting of Zhejiang, China. However, further understanding is needed regarding its long-term effectiveness and feasibility in PHC practices. Our cluster-based RCT will provide the highest level of evidence for the policy development of preventing CVD in a rural PHC of China.

Polypill therapy, subclinical atherosclerosis, and cardiovascular events-implications for the use of preventive pharmacotherapy: MESA (Multi-Ethnic Study of Atherosclerosis)

OBJECTIVES

This study examines whether the coronary artery calcium (CAC) score can be used to define the target population to treat with a polypill.

BACKGROUND

Prior studies have suggested a single polypill to reduce cardiovascular disease (CVD) at the population level.

METHODS

Participants from MESA (Multi-Ethnic Study of Atherosclerosis) were stratified using the criteria of 4 polypill studies (TIPS [The Indian Polycap Study], Poly-Iran, Wald, and the PILL [Program to Improve Life and Longevity] Collaboration). We compared coronary heart disease (CHD) and CVD event rates and calculated the 5-year number needed to treat (NNT) after stratification based on the CAC score.

RESULTS

Among MESA participants eligible for TIPS, Poly-Iran, Wald, and the PILL Collaboration, CAC = 0 was observed in 58.6%, 54.5%, 38.9%, and 40.8%, respectively. The rate of CHD events among those with CAC = 0 varied from 1.2 to 1.9 events per 1,000 person-years, those with CAC scores from 1 to 100 had event rates ranging from 4.1 to 5.5, and in those with CAC scores >100 the event rate ranged from 11.6 to 13.3. The estimated 5-year NNT to prevent 1 CVD event ranged from 81-130 for patients with CAC = 0, 38-54 for those with CAC scores from 1 to 100, and 18-20 for those with CAC scores >100.

CONCLUSIONS

In MESA, among individuals eligible for treatment with the polypill, the majority of CHD and CVD events occurred in those with CAC scores >100. The group with CAC = 0 had a very low event rate and a high projected NNT. The avoidance of treatment in individuals with CAC = 0 could allow for significant reductions in the population considered for treatment, with a more selective use of the polypill and, as a result, avoidance of treatment in those who are unlikely to benefit.

Characteristics of high risk people with cardiovascular disease in Chinese rural areas: clinical indictors, disease patterns and drug treatment

Background and Aims

Current cardiovascular disease (CVD) prevention is based on diagnosis and treatment of specific disease. Little is known for high risk people with CVD at the community level. In rural China, health records of all residents were established after the recent health reforms. This study aims to describe the characters of the rural population with high CVD risk regarding their clinical indicators, disease patterns, drug treatment and adherence.

Methods and Results

17042 (87%) of all the 19500 rural residents in the two townships had valid health records in 2009. We employed a validated tool, the Asian Equation, to screen 8182 (48%) resident health records of those aged between 40–75 years in 2010. Those who were identified with a CVD risk of 20% or higher were selected for a face-to-face questionnaire survey regarding their diagnosed disease and drug treatment. 453 individuals were identified as high risk of CVD, with an average age of 53 years, 62% males, 50% smoking rate and average systolic blood pressure of 161 mmHg. 386 (85%) participated in the survey, while 294 (76%) were diagnosed with and 88 (23%) were suspects of CVD, hypertension, diabetes or hyperlipidaemia. 75 (19%) took drug regularly and 125 (32%) either stopped treatment or missed drugs. The most often used drugs were calcium channel blockers (20%). Only 2% used aspirins and 0.8% used statins. The median costs of drugs were 17 RMB (USD2.66) per month.

Conclusion

The majority of the high risk population in our setting of rural China had already been diagnosed with a CVD related disease, but very few took any drugs, and less still took highly effective drugs to prevent CVD. A holistic strategy focused on population with high risk CVD and based on the current China public health reform is suggested in the context of primary care.

Predictive risk modelling in health: options for New Zealand and Australia

Predictive risk models (PRMs) are case-finding tools that enable health care systems to identify patients at risk of expensive and potentially avoidable events such as emergency hospitalisation. Examples include the PARR (Patients-at-Risk-of-Rehospitalisation) tool and Combined Predictive Model used by the National Health Service in England. When such models are coupled with an appropriate preventive intervention designed to avert the adverse event, they represent a useful strategy for improving the cost-effectiveness of preventive health care. This article reviews the current knowledge about PRMs and explores some of the issues surrounding the potential introduction of a PRM to a public health system. We make a particular case for New Zealand, but also consider issues that are relevant to Australia.

Management of High Blood Pressure in Those without Overt Cardiovascular Disease Utilising Absolute Risk Scores

Increasing blood pressure has a continuum of adverse risk for cardiovascular events. Traditionally this single measure was used to determine who to treat and how vigorously. However, estimating absolute risk rather than measurement of a single risk factor such as blood pressure is a superior method to identify who is most at risk of having an adverse cardiovascular event such as stroke or myocardial infarction, and therefore who would most likely benefit from therapeutic intervention. Cardiovascular disease (CVD) risk calculators must be used to estimate absolute risk in those without overt CVD as physician estimation is unreliable. Incorporation into usual practice and limitations of the strategy are discussed.

Total cardiovascular risk approach to improve efficiency of cardiovascular prevention in resource constrain settings

OBJECTIVES

To determine the population distribution of cardiovascular risk in eight low- and middle-income countries and compare the cost of drug treatment based on cardiovascular risk (cardiovascular risk thresholds ≥ 30%/≥ 40%) with single risk factor cutoff levels.

STUDY DESIGN AND SETTING

Using World Health Organization (WHO) and the International Society of Hypertension risk prediction charts, cardiovascular risk was categorized in a cross-sectional study of 8,625 randomly selected people aged 40-80 years (mean age, 54.6 years) from defined geographic regions of Nigeria, Iran, China, Pakistan, Georgia, Nepal, Cuba, and Sri Lanka. Cost estimates for drug therapy were calculated for three countries.

RESULTS

A large fraction (90.0-98.9%) of the study population has a 10-year cardiovascular risk <20%. Only 0.2-4.8% are in the high-risk categories (≥ 30%). Adopting a total risk approach and WHO guidelines recommendations would restrict unnecessary drug treatment and reduce the drug costs significantly.

CONCLUSION

Adopting a total cardiovascular risk approach instead of a single risk factor approach reduces health care expenditure by reducing drug costs. Therefore, limited resources can be more efficiently used to target high-risk people who will benefit the most. This strategy needs to be complemented with population-wide measures to shift the cardiovascular risk distribution of the whole population.

The Framingham Heart Study's impact on global risk assessment

Cardiovascular disease (CVD) is the leading cause of mortality, responsible for about 30% of deaths worldwide. Globally, 80% of total CVD deaths occur in developing countries. In recent years, age-adjusted CVD death has been cut in half in developed countries. Much of the decline is due to reductions in risk factors that the Framingham Heart Study helped to identify. The Framingham Heart Study also helped to classify those at highest risk by creating multivariate risk scores. As a result, other investigators have created various risk prediction scores for their countries. These scores have been the foundation for guidelines and prevention strategies in developed countries. However, most scores requiring blood tests may be difficult to implement in developing countries where limited resources for screening exist. New studies and risk scores inspired by the Framingham Heart Study need to simplify risk scoring in developing countries so that affordable prevention strategies can be implemented.

Statin use in Canadians: trends, determinants and persistence

BACKGROUND

Regular statin use is an important tool in chronic disease management, lowering cholesterol levels and reducing risk of cardiovascular disease (CVD). The objectives of this study are to describe statin use in Canada by comorbidity and lifestyle risk factors, and determine persistence in statin use.

METHODS

The longitudinal National Population Health Survey, 1994-2002, is a random sample of the 1994 Canadian population and five interviews were conducted at two-year intervals. A total of 8,198 respondents, aged 20 in 1994, completed all five interviews. Information collected included demographic variables, medication use, CVD lifestyle risk factors, CVD, diabetes and hypertension.

RESULTS

Age-adjusted rates of statin use increased from 1.6% to 7.8% over the period 1994-2002. Statin use was higher with increasing age, diabetes, BMI, physician visits, and insurance for prescription medication. Although persons with CVD were more likely to take statins than those without, by 2002 still only 32.7% of heart patients were taking statins. Statin use did not increase linearly with increasing numbers of CVD risk factors or comorbidities. Of the 441 persons reporting statin use in 2000, 74.6% were still taking them in 2002. People who completed their high school education were more likely to continue taking statins than those who did not complete high school.

CONCLUSION

While statin use increased over time, was associated with CVD and diabetes, and to a lesser extent with increased BMI, a substantive underuse in high-risk patients remains. Helping high-risk people to increase statin use continues to be a priority for health care professionals.

Effects of a fixed combination of perindopril and indapamide on macrovascular and microvascular outcomes in patients with type 2 diabetes mellitus (the ADVANCE trial): a randomised controlled trial

BACKGROUND

Blood pressure is an important determinant of the risks of macrovascular and microvascular complications of type 2 diabetes, and guidelines recommend intensive lowering of blood pressure for diabetic patients with hypertension. We assessed the effects of the routine administration of an angiotensin converting enzyme (ACE) inhibitor-diuretic combination on serious vascular events in patients with diabetes, irrespective of initial blood pressure levels or the use of other blood pressure lowering drugs.

METHODS

The trial was done by 215 collaborating centres in 20 countries. After a 6-week active run-in period, 11 140 patients with type 2 diabetes were randomised to treatment with a fixed combination of perindopril and indapamide or matching placebo, in addition to current therapy. The primary endpoints were composites of major macrovascular and microvascular events, defined as death from cardiovascular disease, non-fatal stroke or non-fatal myocardial infarction, and new or worsening renal or diabetic eye disease, and analysis was by intention-to-treat. The macrovascular and microvascular composites were analysed jointly and separately. This trial is registered with ClinicalTrials.gov, number NCT00145925.

FINDINGS

After a mean of 4.3 years of follow-up, 73% of those assigned active treatment and 74% of those assigned control remained on randomised treatment. Compared with patients assigned placebo, those assigned active therapy had a mean reduction in systolic blood pressure of 5.6 mm Hg and diastolic blood pressure of 2.2 mm Hg. The relative risk of a major macrovascular or microvascular event was reduced by 9% (861 [15.5%] active vs 938 [16.8%] placebo; hazard ratio 0.91, 95% CI 0.83-1.00, p=0.04). The separate reductions in macrovascular and microvascular events were similar but were not independently significant (macrovascular 0.92; 0.81-1.04, p=0.16; microvascular 0.91; 0.80-1.04, p=0.16). The relative risk of death from cardiovascular disease was reduced by 18% (211 [3.8%] active vs 257 [4.6%] placebo; 0.82, 0.68-0.98, p=0.03) and death from any cause was reduced by 14% (408 [7.3%] active vs 471 [8.5%] placebo; 0.86, 0.75-0.98, p=0.03). There was no evidence that the effects of the study treatment differed by initial blood pressure level or concomitant use of other treatments at baseline.

INTERPRETATION

Routine administration of a fixed combination of perindopril and indapamide to patients with type 2 diabetes was well tolerated and reduced the risks of major vascular events, including death. Although the confidence limits were wide, the results suggest that over 5 years, one death due to any cause would be averted among every 79 patients assigned active therapy.

Cost-effectiveness analysis of hypertension guidelines in South Africa: absolute risk versus blood pressure level

BACKGROUND

Hypertension is responsible for more deaths worldwide than any other cardiovascular risk factor. Guidelines based on blood pressure level for initiation of treatment of hypertension may be too costly compared with an approach based on absolute cardiovascular disease (CVD) risk, especially in developing countries.

METHODS AND RESULTS

Using a Markov CVD model, we compared 6 strategies for initiation of drug treatment--2 different blood pressure levels (160/95 and 140/90 mm Hg) and 4 different levels of absolute CVD risk over 10 years (40%, 30%, 20%, and 15%)--with one of no treatment. We modeled a hypothetical cohort of all adults without CVD in South Africa, a multiethnic developing country, over 10 years. The incremental cost-effectiveness ratios for treating those with 10-year absolute risk for CVD >40%, 30%, 20%, and 15% were 700 dollars, 1600 dollars, 4900 dollars, and 11,000 dollars per quality-adjusted life-year gained, respectively. Strategies based on a target blood pressure level were both more expensive and less effective than treatment decisions based on the strategy that used absolute CVD risk of >15%. Sensitivity analysis of cost of treatments, prevalence estimates of risk factors, and benefits expected from treatment did not change the ranking of the strategies.

CONCLUSIONS

In South Africa, current guidelines based on blood pressure levels are both more expensive and less effective than guidelines based on absolute risk of cardiovascular disease. The use of quantitative risk-based guidelines for treatment of hypertension could free up major resources for other pressing needs, especially in developing countries.

Measures of global risk: old versus new methods

It is clear that atherosclerotic arterial disease has a multifactorial aetiology. Furthermore relatively modest elevations of two or more risk factors frequently coexist in individuals to produce a significant impact on the likelihood of a cardiovascular event. Nevertheless clinical practice has tended to be unifactorial, with physicians concentrating on single risk factors in isolation. Various scores using data on several risk factors have therefore been developed to help physicians assess which of their patients are most at risk and therefore most merit intervention. This global risk assessment is increasingly recognised in management guidelines as a reasonable way of guiding treatment. Indeed intervention strategies that do not target those at highest cardiovascular risk--(and currently available risk scores do this more efficiently than physicians' judgement)--are less likely to be cost effective. It must be acknowledged however that all risk scores have limitations and hence whichever method is used should be used to guide rather than rule practice.

Towards more effective use of decision support in clinical practice: what the guidelines for guidelines don’t tell you

The Brisbane Cardiac Consortium Clinical Support Systems Program used multiple strategies in optimising quality of care of patients with either of two cardiac conditions. One of these strategies was the development and active implementation of decision support systems centred on evidence-based, locally agreed clinical practice guidelines. Our experience in undertaking this task highlighted numerous operational challenges for which solutions were difficult to extract from existing published literature. In the present article we provide a methodology grounded in both theory and real-world experience that may assist others in developing and implementing systems of guideline-based decision support.

Description and validation of a Markov model of survival for individuals free of cardiovascular disease that uses Framingham risk factors

Background

Estimation of cardiovascular disease risk is increasingly used to inform decisions on interventions, such as the use of antihypertensives and statins, or to communicate the risks of smoking. Crude 10-year cardiovascular disease risk risks may not give a realistic view of the likely impact of an intervention over a lifetime and will underestimate of the risks of smoking. A validated model of survival to act as a decision aid in the consultation may help to address these problems. This study aims to describe the development of such a model for use with people free of cardiovascular disease and evaluates its accuracy against data from a United Kingdom cohort.

Methods

A Markov cycle tree evaluated using cohort simulation was developed utilizing Framingham estimates of cardiovascular risk, 1998 United Kingdom mortality data, the relative risk for smoking related non-cardiovascular disease risk and changes in systolic blood pressure and serum total cholesterol total cholesterol with age. The model's estimates of survival at 20 years for 1391 members of the Whickham survey cohort between the ages of 35 and 65 were compared with the observed survival at 20-year follow-up.

Results

The model estimate for survival was 75% and the observed survival was 75.4%. The correlation between estimated and observed survival was 0.933 over 39 subgroups of the cohort stratified by estimated survival, 0.992 for the seven 5-year age bands from 35 to 64, 0.936 for the ten 10 mmHg systolic blood pressure bands between 100 mmHg and 200 mmHg, and 0.693 for the fifteen 0.5 mmol/l total cholesterol bands between 3.0 and 10.0 mmol/l. The model significantly underestimated mortality in those people with a systolic blood pressure greater than or equal to 180 mmHg (p = 0.006).

The average gain in life expectancy from the elimination of cardiovascular disease risk as a cause of death was 4.0 years for all the 35 year-old men in the sample (n = 24), and 1.8 years for all the 35 year-old women in the sample (n = 32).

Conclusions

This model accurately estimates 20-year survival in subjects from the Whickham cohort with a systolic blood pressure below 180 mmHg.

Prediction of cardiovascular risk in people with diabetes

People with diabetes are at high risk of cardiovascular morbidity and mortality, especially if they have already developed vascular problems. For patients who are apparently free of vascular complications, risk tables are often used to assess the risk of cardiovascular events in the following years, and to decide on treatment with statins or anti-platelet therapy. These risk prediction tables include estimates of traditional cardiovascular risk factors and are based on populations, some of which only contained a very small number of people with diabetes. Multiple problems can be identified with these tables, and many seriously underestimate cardiovascular risk in people with diabetes. Possible ways of addressing this include using risk estimation tools based solely on diabetic populations, adding in additional traditional variables such as triglycerides or left ventricular hypertrophy, including novel cardiovascular risk factors, or intervening at a lower level of estimated risk in people with diabetes compared with non-diabetic subjects. Alternatively, estimates of individual risk could be abandoned and all people with diabetes could be treated with statins and other effective agents.

Prediction of coronary heart disease: a comparison between the Copenhagen risk score and the Framingham risk score applied to a Dutch population

OBJECTIVES

To compare the estimation of coronary heart disease (CHD) risk by the Framingham risk score (FRS) and the Copenhagen risk score (CRS) using Dutch population data.

DESIGN

Comparison of CHD risk estimates from FRS and CRS. CHD risk-estimations for each separate risk factor.

SETTING

Urk, the Netherlands.

SUBJECTS

A total of 408 fishermen from Urk, aged 30-65 years, without pre-existing cardiovascular disease.

MAIN OUTCOME MEASURES

Absolute CHD risk estimates.

RESULTS

The average 10-year risk for CHD was significantly different between the FRS (4.6%, SD 5.0) and the CRS (3.2%, SD 4.1). The correlation between the two estimates was 0.94 (P < 0.001). The Bland-Altman figure shows a large proportion of agreement, but with an increasing difference with increasing average risk. When examining the separate risk factors age, total cholesterol, HDL cholesterol and systolic blood pressure and smoking, there appear differences between the two risk functions.

CONCLUSION

Using Dutch population data, differences were found for the calculation of CHD risk with the FRS and the CRS. Further research must be carried out to examine the validity of these risk functions in the Dutch population.

Benefits of treating hypertension in the elderly: should age affect treatment decisions?

Do the benefits of treating hypertension extend equally to all age groups, particularly the very elderly? Several large controlled trials have been published in recent years that confirm the benefits of the treatment of hypertension in terms of morbidity and mortality. However, these trials included only relatively small numbers of patients aged > or = 80 years. Data regarding such patients have been extracted and subjected to meta-analysis, but with inconclusive results. Further difficulties arise as a result of the range of therapeutic agents employed. Therefore, uncertainty still surrounds the value of treating very elderly patients with hypertension. The J-curve hypothesis, i.e. that a blood pressure threshold exists below which there is an increase in the rate of cardiac events, has been a concern in treating elderly patients. Upon close examination, this appears to be spurious. The Hypertension in the Very Elderly Trial study sets out to provide conclusive evidence for the benefits or otherwise of treating hypertension in the very elderly and has just commenced. The results of this trial will not be available for some time. In the meantime, should physicians initiate or continue treatment for very elderly individuals with hypertension? If so, what regimens should be employed and should target blood pressure levels be set? At the present time, it would appear sensible to provide treatment for very elderly patients with hypertension, particularly those with evidence of complications or target organ damage. In relatively healthy individuals with mild-to-moderate hypertension, the guiding principle should be 'the lower the blood pressure the better'. Regarding the choice of therapeutic agent, a low-dose diuretic remains the first choice therapy.

Using disease risk estimates to guide risk factor interventions: field test of a patient workbook for self-assessing coronary risk

OBJECTIVE

To assess the feasibility and acceptability of a patient workbook for self-assessing coronary risk.

DESIGN

Pilot study, with post-study physician and patient interviews.

SETTING AND SUBJECTS

Twenty southern Ontario family doctors and 40 patients for whom they would have used the workbook under normal practice conditions.

INTERVENTIONS

The study involved convening two sequential groups of family physicians: the first (n=10) attended focus group meetings to help develop the workbook (using algorithms from the Framingham Heart Study); the second (n=20) used the workbook in practice with 40 patients. Follow-up interviews were by interviewer-administered questionnaire.

MAIN OUTCOMES MEASURES

Physicians' and patients' opinions of the workbook's format, content, helpfulness, feasibility, and potential for broad application, as well as patients' perceived 10-year risk of a coronary event measured before and after using the workbook.

RESULTS

It took an average of 18 minutes of physician time to use the workbook: roughly 7 minutes to introduce it to patients, and about 11 minutes to discuss the results. Assessments of the workbook were generally favourable. Most patients were able to complete it on their own (78%), felt they had learned something (80%) and were willing to recommend it to someone else (98%). Similarly, 19 of 20 physicians found it helpful and would use it in practice with an average of 18% of their patients (range: 1-80%). The workbook helped to correct misperceptions patients had about their personal risk of a coronary event over the next 10 years (pre-workbook (mean (SD) %): 35.2 (16.9) vs. post-workbook: 17.3 (13.5), P < 0.0001; estimate according to algorithm: 10.6 (7.6)).

CONCLUSIONS

Given a simple tool, patients can and will assess their own risk of CHD. Such tools could help inform otherwise healthy individuals that their risk is increased, allowing them to make more informed decisions about their behaviours and treatment.

Meeting the National Service Framework for coronary heart disease: which patients have untreated high blood pressure?

BACKGROUND

The National Service Framework for coronary heart disease requires primary care teams to identify patients who are at high risk of cardiovascular events and treat those with high blood pressure. However, there are no data on how many must be assessed, how much cardiovascular disease can be prevented or which patients are most likely to benefit.

AIM

To estimate the potential number of patients who are eligible for blood pressure assessment, the number of preventable cardiovascular disease events and the relative efficiency of the strategy in different age groups.

DESIGN OF STUDY

Modelling exercise.

SETTING

Hypothetical population of 100,000.

METHOD

The age-sex specific prevalence of cardiovascular risk factors and of current anti-hypertensive treatment were obtained from published sources and combined with published estimates of the effectiveness of anti-hypertensive treatment. From these data were calculated numbers of persons eligible for assessment and treatment, and numbers of preventable cardiovascular events.

RESULTS

There were 79,607 persons eligible for assessment and 5888 eligible for treatment. Treatment could prevent between 101 and 139 cardiovascular events annually. There were 11,571 persons aged over 65 years and eligible for assessment and 4655 eligible for treatment. Treatment could prevent 85 to 117 cardiovascular events annually. No cardiovascular events are prevented in persons aged under 45 years.

CONCLUSION

Confining assessment to the 16% who are aged over 65 years prevents 85% of the population's avoidable cardiovascular disease. Primary care teams should assess and treat persons aged over 65 years before assessing younger patients. No health benefit results from assessing persons aged under 45 years.

Selected complementary methods and nursing care of the hypertensive client

The National Institutes of Health and the World Health Organization have targeted the treatment of mild or borderline hypertension as a critical health care issue. Conventional practitioners' focus on more intensive treatment for blood pressure elevations in the lower ranges is accompanying the consumer-driven movement toward the use of complementary methods. Over 60 million Americans used herbal therapies in the past year, and visits to complementary care practitioners are expected to increase beyond the 425 million now made annually. The purpose of this article is to identify four herbs that consumers commonly select for the treatment of hypertension and identify nursing care considerations for their use. Additionally, the article reviews research on the effectiveness of acupuncture for hypertension, along with nursing care implications for patients.

Blood pressure and mortality during an up to 32-year follow-up

BACKGROUND

Elevated blood pressure is an established risk factor of cardiovascular diseases, but there is a constant debate whether the association is continuous or with a threshold.

METHODS

During the 1960s (1964 onwards), 3,267 initially healthy male business executives (born 1919-1934) participated in voluntary health check-ups with measurements of cardiovascular disease risk factors. At baseline none of the men were on antihypertensive medication. Mortality follow-up was performed using national registers up to 31 December, 1995. Follow-up total and cardiovascular mortality was related to systolic (by 10 mmHg) and diastolic (by 5 mmHg, Korotkoff's 4th phase) blood pressure at baseline. Analyses were adjusted for age, body mass index, smoking and serum cholesterol.

RESULTS

During an up to 32-year follow-up, there were 701 deaths, 234 (33.4%) of them due to coronary heart disease, 49 (7.0%) to stroke, 42 (6.0%) to other cardiovascular diseases and 204 (29.1%) to cancer. Total mortality curves of the whole cohort (all age groups) were flat until 131-140 mmHg (systolic) and 81-85 (diastolic) and increased thereafter. Among men who smoked and had baseline serum cholesterol > 6.5 mmol/l (n = 986), the risk of death increased progressively with systolic blood pressure, whereas among non-smoking normocholesterolaemic men (n = 504) the association was J-shaped, i.e. higher mortality at < or = 110 mmHg than between 111-150 mmHg and a more consistent rise from 151-160 mmHg. The curves were essentially similar for cardiovascular mortality. The results were supported by analyses where major cardiovascular risk factors were controlled.

CONCLUSION

During a truly long-term follow-up, the relationship between systolic blood pressure and mortality was initially flat up to 131-140 mmHg although a linear relationship is suggested in men with other cardiovascular risk factors.

At what level of coronary heart disease risk should a statin be prescribed?

Statin therapy has been conclusively shown to offer patients clinical benefit, virtually irrespective of their baseline risk status. However, the absolute risk reductions observed in different clinical trials, which have recruited patients across a spectrum of lipid levels and vascular disease states, show that baseline global risk determines the absolute benefit gained and in turn will specify the number of patients needed to be treated in order to realize this benefit. Global risk assessment is therefore central to the clinically meaningful use of statin therapy, and a strong case is now argued in the literature for a high-risk primary prevention strategy that goes hand in hand with standard secondary prevention. The routine use of Framingham-based risk assessment tools is advocated because these are the most widely evaluated and have been repeatedly shown to predict the risk of coronary heart disease accurately in western populations. The risk threshold in primary prevention that should determine pharmacological intervention is the subject of controversy. The currently used annual risk figure of 3% would clearly capture all very high-risk individuals but would also deny treatment to many individuals who will subsequently die from their first coronary event. Although a 1.5% annual risk threshold is economically untenable in the present UK health system, a level of 2% is, we believe, both achievable and affordable.