Total cardiovascular risk assessment and management using two prediction tools, with and without blood cholesterol

Abstract

Introduction: Over the last decade, total cardiovascular risk assessment and management has been recommended by cardiovascular prevention guidelines in most high-income countries and by WHO. Cardiovascular risk prediction charts have been developed based on multivariate equations of values of some well-known risk factors such as age, sex, smoking, systolic blood pressure and diabetes, including or omitting total blood cholesterol.

Objective: The objectives of this study were: to determine the distribution of cardiovascular risk in a Cuban population using the WHO/International Society of Hypertension risk prediction charts with and without cholesterol; and to assess applicability of the risk prediction tool without cholesterol in a middle-income country, by evaluating concordance between the two approaches and comparing projected drug requirements resulting from each (at risk thresholds of ≥20% and ≥30%) and for the single-risk-factor approach.

Methods: From April through December 2008, a cross-sectional study was conducted in 1287 persons (85.8% of the sample selected), aged 40-80 years living in a polyclinic catchment area of Havana, Cuba, based on the protocol and data from a WHO multinational study. The study used the two sets of the WHO and the International Society of Hypertension (WHO/ISH) risk prediction charts, with and without cholesterol. Percentages and means were calculated, as well as prevalence (%) of risk factors. The chi-square test was used to compare means (p ≤0.05). Concordance between the two prediction charts was calculated for different risk levels, using the chart with cholesterol as a reference.

Results: Using the risk assessment tools with and without cholesterol, 97.1% and 95.4% respectively of the study population were in the ten-year cardiovascular risk category of <20%, while 2.9% and 4.6% respectively were in the category of ≥20%. Risk categories were concordant in 88.1% of the population; overestimation was higher among the nonconcordant (136/153). When risk assessment did not include cholesterol, there was 2.6% (34/1287) overestimation of drug requirements and 0.5% (6/1287) underestimation, compared to estimates including cholesterol.

Conclusion: Total cardiovascular risk assessment using the WHO/ISH charts without cholesterol could be a useful approach to predict cardiovascular risk in settings where cholesterol cannot be measured. This does not introduce overconsumption of drugs, but does enable better targeting of resources to those who are more likely to develop cardiovascular disease. KEYWORDS Cardiology, risk assessment, health risk appraisal, hypertension, health policy, cost savings, atherosclerosis, Cuba.