Coronary and cardiovascular risk estimation in uncomplicated mild hypertension. A comparison of risk assessment methods

Cost-effectiveness analysis of combining traditional Chinese medicine in the treatment of hypertension: compound Apocynum tablets combined with Nifedipine sustained-release tablets vs Nifedipine sustained-release tablets alone

Background

We evaluated the long-term cost-effectiveness of antihypertensive traditional Chinese medicines (TCMs) and to compare the cost-effectiveness of a combined treatment consisting of compound Apocynum tablets and Nifedipine sustained-release tablets with the cost-effectiveness of treatment with Nifedipine sustained-release tablets alone.

Methods

A Markov model was used to simulate the potential incremental cost-effectiveness per quality-adjusted life year (QALY) to be gained from compound Apocynum tablets and Nifedipine sustained-release tablets compared with Nifedipine sustained-release tablets alone. Model parameter estimates were informed by previously published studies. The direct medical costs of outpatients with hypertension were estimated from the health care provider’s perspective. A 5% annual discount rate was applied to both costs and QALYs.

Results

TCMs combined with Nifedipine sustained-release tablets group generated a total 20-year cost of 11,517.94 RMB (US $1739.87), whereas Nifedipine sustained-release tablets alone group resulted in a 20-year cost of 7253.71 RMB (US $1095.73). TCMs combined with Nifedipine sustained-release tablets group resulted in a generation of 12.69 QALYs, whereas Nifedipine sustained-release tablets alone group resulted in 12.50. The incremental cost-utility ratio was 22,443.32 RMB (US $3390.23) per QALY. Considering the threshold of 1 GDP per capita in China in 2018 (US $9764.95), the combination of compound Apocynum tablets and Nifedipine sustained-release tablets was a cost-effective strategy. One-way and probabilistic sensitivity analysis showed unchanged results over an acceptable range.

Conclusions

Combining Traditional Chinese Medicines with chemical medicines is more cost-effective strategy in the treatment of hypertension.

Evaluation of the performance of existing non-laboratory based cardiovascular risk assessment algorithms

Background

The high burden and rising incidence of cardiovascular disease (CVD) in resource constrained countries necessitates implementation of robust and pragmatic primary and secondary prevention strategies. Many current CVD management guidelines recommend absolute cardiovascular (CV) risk assessment as a clinically sound guide to preventive and treatment strategies. Development of non-laboratory based cardiovascular risk assessment algorithms enable absolute risk assessment in resource constrained countries.

The objective of this review is to evaluate the performance of existing non-laboratory based CV risk assessment algorithms using the benchmarks for clinically useful CV risk assessment algorithms outlined by Cooney and colleagues.

Methods

A literature search to identify non-laboratory based risk prediction algorithms was performed in MEDLINE, CINAHL, Ovid Premier Nursing Journals Plus, and PubMed databases. The identified algorithms were evaluated using the benchmarks for clinically useful cardiovascular risk assessment algorithms outlined by Cooney and colleagues.

Results

Five non-laboratory based CV risk assessment algorithms were identified. The Gaziano and Framingham algorithms met the criteria for appropriateness of statistical methods used to derive the algorithms and endpoints. The Swedish Consultation, Framingham and Gaziano algorithms demonstrated good discrimination in derivation datasets. Only the Gaziano algorithm was externally validated where it had optimal discrimination. The Gaziano and WHO algorithms had chart formats which made them simple and user friendly for clinical application.

Conclusion

Both the Gaziano and Framingham non-laboratory based algorithms met most of the criteria outlined by Cooney and colleagues. External validation of the algorithms in diverse samples is needed to ascertain their performance and applicability to different populations and to enhance clinicians’ confidence in them.

Agreement among cardiovascular disease risk calculators

BACKGROUND

Use of cardiovascular disease risk calculators is often recommended by guidelines, but research on consistency in risk assessment among calculators is limited.

METHOD AND RESULTS

A search of PubMed and Google was performed. Five clinicians selected 25 calculators by independent review. Hypothetical patients were created with the use of 7 risk factors (age, sex, smoking, blood pressure, high-density lipoprotein, total cholesterol, and diabetes mellitus) dichotomized to high and low, generating 2(7) patients (128 total). These patients were assessed by each calculator by 2 clinicians. Risk estimates (and assigned risk categories) were compared among calculators. Selected calculators were from 8 countries, used 5- or 10-year predictions, and estimated either cardiovascular disease or coronary heart disease. With the use of 3 risk categories (low, medium, and high), the 25 calculators categorized each patient into a mean of 2.2 different categories, and 41% of unique patients were assigned across all 3 risk categories. Risk category agreement between pairs of calculators was 67%. This did not improve when analysis was limited to just the 10-year cardiovascular disease calculators. In nondiabetics, the highest calculated risk estimate from a calculator averaged 4.9 times higher (range, 1.9-13.3) than the lowest calculated risk estimate for the same patient. This did not change meaningfully for diabetics or when the analysis was limited to 10-year cardiovascular disease calculators.

CONCLUSIONS

The decision as to which calculator to use for risk estimation has an important impact on both risk categorization and absolute risk estimates. This has broad implications for guidelines recommending therapies based on specific calculators.

Chinese herbal formulas for treating hypertension in traditional Chinese medicine: perspective of modern science

Hypertension, which directly threatens quality of life, is a major contributor to cardiovascular and cerebrovascular events. Over the past two decades, domestic and foreign scholars have agreed upon various standards in the treatment of hypertension, and considerable progress has been made in the field of antihypertensive drugs. Oral antihypertensive drugs represent a milestone in hypertension therapy. However, the blood pressure standard for patients with hypertension is far from satisfactory. The study of Chinese herbal formulas for treating hypertension has received much research attention. These studies seek to integrate traditional and Western medicine in China. Currently, Chinese herbal formulas are known to have an outstanding advantage with regard to bodily regulation. Research shows that Chinese medicine has many protective mechanisms. This paper addresses the process of the antihypertensive mechanisms in Chinese herbal formulas for treating hypertension. These mechanisms are to be discussed in future research.

The "Five Risks algorithm": an easy tool for cardiovascular risk estimation

The aim of this study is to provide an easy tool to identify patients with a high cardiovascular risk, especially those qualifying for lipid-lowering treatment. The decision to treat with lipid-lowering drugs was assessed with five new risk algorithms. The Five Risk algorithm (5R) takes into account male gender, high systolic blood pressure, high total cholesterol, smoking and high blood sugar as independent risk factors. Patients with three independent risk factors qualify for lipid-lowering treatment. Compared to the Framingham Risk Score, the 5R has a Kappa coefficient of 0.62. Compared to the SCORE, the Six Risk algorithm (6RDF) has a Kappa coefficient of 0.70. The 6RDF uses only four independent risk factors (male gender, high systolic blood pressure, high total cholesterol and smoking) but having diabetes or a family history of premature coronary heart disease are exclusion criteria for which treatment with lipid-lowering drugs is always indicated.

A selection-bias free method to estimate the prevalence of hypertension from an administrative primary health care database in the Girona Health Region, Spain

The prevalence of common illnesses could be estimated using general practice databases, providing certain advantages when compared to other alternative sources of information, in particular being relatively more cost-effective. The main limitation is that it is a threat of selection bias. Some individuals have a higher probability of having used primary health care, implying that the potential result, 'contact registration', is overrepresented in the sample observed. The selection bias would provide inconsistent estimators of prevalence. The objective of this study is to propose a bias-free selection method to estimate prevalence using an administrative primary health care database. It proposes re-weighting the estimations of prevalence obtained from the database according to the probability of their being present in the same. These probabilities will be appropriately estimated from a health survey using a treatment effects model with a discrete response, i.e. a hurdle model. As an application, it was estimated the prevalence of hypertension in the population covered by public primary health care providers in the Girona Health Region, Spain, in 2005. Using this bias-free selection method the prevalence of hypertension has been estimated that 15.5% of individuals aged 15 and above (14.1% among men and 16.9% among women) suffer from hypertension. Likewise, the prevalence is estimated at 31.1% (30.3% men and 32.0% women) in individuals aged 45 and over; 48.3% (44.1% men and 51.9% women) among those aged 65 and over; and 13.1% (11.8% men and 13.9% women) in the general population. The proposed method provides estimators of the prevalence of hypertension very close to those obtained directly from the 2006 Catalan Health Survey. It is concluded that the proposed method could be used to estimate the prevalence of hypertension in an approximately unbiased form. Given the use of the administrative primary health care database corresponding to all users of primary health care in the 23 public managed Health Areas of the Girona Health Region during 2005, the proposed method will be more cost-effective and will provide much more population information than health questionnaires.

Cardiovascular risk assessment in hypertensive patients: major discrepancy according to ESH and SCORE strategies

BACKGROUND

The European Society of Hypertension (ESH) guidelines recommend two possible strategies for the assessment of cardiovascular risk (CVR) in essential hypertensive (HT) patients: categorical tables and SCORE risk charts. However, the outcome of these methods has not been compared.

OBJECTIVE AND METHODS

We assessed CVR according to ESH and SCORE risk charts adapted to use in Belgium in 106 HT patients (mean age: 52.4 +/- 12.9 years, male/female ratio: 46/60) without diabetes or other associated clinical conditions.

RESULTS

The distribution of low, moderate, high and very high added risk was strikingly different (kappa coefficient = 0.08) according to ESH categorical tables (n = 1, 24, 24, 57) and SCORE risk charts (n = 60, 12, 10, 24). Furthermore, compared with ESH, CVR class according to SCORE was lower in the majority of patients (n = 72, 68%) while it was similar in 23 (22%) and higher in 11 patients (10%). Patients for whom risk was lower by SCORE compared to ESH differed from the others by age (46.7 +/- 10.0 versus 64.6 +/- 9.2, P < 10) and proportion of females (71 versus 26%, P < 10).

CONCLUSIONS

In this series of patients with mainly moderate or severe hypertension, the distribution of cardiovascular risk was strikingly different according to ESH categorical tables and SCORE risk charts. This might be explained in part by the lower weight attributed to blood pressure in risk assessment, especially in young female subjects. If confirmed, these results should prompt the performance of a prospective study to assess which strategy most accurately predicts CVR in hypertensive patients.

Intensive cardiovascular examination regarding blood pressure levels: evaluation of risk groups. ICEBERG study

OBJECTIVE

Assessment of total cardiovascular risk level is crucial for approaching hypertensive patients. Therefore, the aim of the Intensive/Initial Cardiovascular Examination regarding Blood pressure levels: Evaluation of Risk Groups (ICEBERG) study is to determine cardiovascular risk evaluation and stratification of subjects with high normal and high blood pressure (BP > or = 130/85 mmHg), and to evaluate the impact of laboratory tests on this stratification.

METHODS

ICEBERG was an epidemiological study conducted at 20 university hospitals and 197 primary healthcare centers. A total of 10,313 patients, who were diagnosed with high BP and under antihypertensive treatment or not antihypertensive under treatment at least for the last 3 months were selected. Besides routine clinical evaluation, microalbuminuria (MAU) and high sensitive C-reactive protein (hs-CRP) tests, echocardiography (Echo) and carotid ultrasonography (USG) were performed in selected arms. The patients were stratified into low, moderate, high and very high added risk groups as described by the European Society of Hypertension/European Society of Cardiology Guidelines Committee (2003).

RESULTS

Upon routine evaluation, the percentage of "high and very high added cardiovascular risk" groups was between 51.2% and 60.7% in different study arms. This percentage increased to 62.9% by subsequent serum biochemistry assessment and to 76.2% by hs-CRP test results. Switching upwards to "high and very high added risk" groups was around 6% when MAU results were used, with a 4.9% upwards switch to "high and very high added risk" groups when Echo was performed; this proportion increased by 6.8%, when carotid USG was taken into account.

CONCLUSION

Cardiovascular risk evaluation by intensive cardiovascular examination including Echo and carotid USG provided more accurate risk stratification. Furthermore, a simple test to demonstrate presence of MAU usable at primary healthcare level will also help to evaluate the patient's risk profile better than routine assessment methods alone.

Trends in hypertension care in eastern and south-western Finland during 1982–2002

OBJECTIVE

To assess the trends in blood pressure (BP) levels and the control of hypertension in eastern and south-western Finland during 1982-2002.

DESIGN

Five independent cross-sectional population surveys conducted in 1982, 1987, 1992, 1997 and 2002.

SETTING

The provinces of North Karelia and Kuopio in eastern Finland and the region of Turku-Loimaa in south-western Finland.

PARTICIPANTS

Stratified random samples of men and women aged 25-64 years were selected from the national population register. The total number of participants was 29 127.

MAIN OUTCOME MEASURES

Mean systolic blood pressure (SBP) and diastolic blood pressure (DBP), the prevalence and control of hypertension. The distribution of all subjects with no antihypertensive drug treatment in 2002 according to the modified risk stratification scheme introduced in 2003 European Society of Hypertension-European Society of Cardiology guidelines.

RESULTS

Mean SBP and DBP and the prevalence of hypertension decreased significantly in all areas. The proportion of treated hypertensive subjects with adequately controlled BP (SBP < 140 mmHg and DBP < 90 mmHg) increased from 13.7 to 33.3% in men (P < 0.001) and from 11.4 to 32.0% in women (P < 0.001). The unsatisfactory treatment of hypertension was mainly a result of the lack of control of high SBP. According to the 2003 guidelines, 35.9% of the entire population currently not on antihypertensive drug treatment should have been prescribed such treatment within a year.

CONCLUSIONS

Hypertension care has improved significantly in Finland during 1982-2002. However, the difference between the actual situation at the population level and the treatment goals presented by the hypertension guidelines remains vast.

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.

Advantages of new cardiovascular risk-assessment strategies in high-risk patients with hypertension

BACKGROUND

Accurate assessment of cardiovascular disease (CVD) risk in patients with hypertension is important when planning appropriate treatment of modifiable risk factors. The causes of CVD are multifactorial, and hypertension seldom exists as an isolated risk factor. Classic models of risk assessment are more accurate than a simple counting of risk factors, but they are not generalizable to all populations. In addition, the risk associated with hypertension is graded, continuous, and independent of other risk factors, and this is not reflected in classic models of risk assessment.

OBJECTIVE

This article is intended to review both classic and newer models of CVD risk assessment.

METHODS

MEDLINE was searched for articles published between 1990 and 2005 that contained the terms cardiovascular disease, hypertension, or risk assessment. Articles describing major clinical trials, new data about cardiovascular risk, or global risk stratification were selected for review.

RESULTS

Some patients at high long-term risk for CVD events (eg, patients aged <50 years with multiple risk factors) may go untreated because they do not meet the absolute risk-intervention threshold of 20% risk over 10 years with the classic model. Recognition of the limitations of classic risk-assessment models led to new guidelines, particularly those of the European Society of Hypertension-European Society of Cardiology. These guidelines view hypertension as one of many risk and disease factors that require treatment to decrease risk. These newer guidelines include a more comprehensive range of risk factors and more finely graded blood pressure ranges to stratify patients by degree of risk. Whether they accurately predict CVD risk in most populations is not known. Evidence from the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) study, which stratified patients by several risk and disease factors, highlights the predictive value of some newer CVD risk assessments.

CONCLUSION

Modern risk assessments, which include blood pressure along with a wide array of modifiable risk factors, may be more accurate than classic models for CVD risk prediction.

What can we expect from new guidelines?

New guidelines for the treatment of hypertension are being published, starting with the seventh report of the US Joint National Committee. These guidelines are certain to address the major developments that have been presented over the past few years. These include the risks of any level of increased blood pressure, either alone or in concert with other known risk factors; the value of out-of-office blood pressure measurements; the preventive potential of lifestyle changes; the results of multiple prospective comparative trials, which have largely negated the quest for the best initial choice of therapy; and the need to increase adherence to enough therapy to reach the appropriate goal for each patient.

Risk stratification by guidelines compared with risk assessment by risk equations applied to a MONICA sample

BACKGROUND

The World Health Organization/International Society of Hypertension (WHO/ISH) Hypertension Guidelines from 1999 propose a risk stratification scheme for estimating absolute risk for cardiovascular disease (CVD). Risk equations estimated by statistical methods are another way of predicting cardiovascular risk.

OBJECTIVE

We studied the differences between these two approaches when applied to the same set of individuals with high blood pressure.

DESIGN AND METHODS

The two northernmost counties in Sweden (NSW) constitute one of the centres in the WHO MONICA (monitoring trends and determinants in cardiovascular disease) Project. Three population surveys have been carried out in 1986, 1990 and 1994, and were used to estimate a risk equation for predicting the 10-year risk of fatal/non-fatal stroke and myocardial infarction. Another MONICA sample from 1999, a total of 5997 subjects, was classified according to the recent WHO/ISH risk stratification scheme. A risk assessment was also performed, by using the risk equations from the NSW MONICA sample and Framingham risk equations.

RESULTS

The agreement between the two methods was good when the values obtained from the risk equation were averaged for each risk group obtained from the risk classification by guidelines. However, if the predicted risk for each individual was considered, the agreement was poor for the medium and high-risk groups. Although the average risk for all individuals is the same, many subjects have a higher risk or a lower risk than predicted by guidelines.

CONCLUSIONS

Risk classification by the 1999 WHO/ISH Hypertension Guidelines is not accurate and detailed enough for medium- and high-risk patients, which could be of clinical importance in the medium risk group.