BackgroundAll rigorous primary cardiovascular disease (CVD) prevention guidelines recommend absolute CVD risk scores to identify high- and low-risk patients, but laboratory testing can be impractical in low- and middle-income countries. The purpose of this study was to compare the ranking performance of a simple, non-laboratory-based risk score to laboratory-based scores in various South African populations.MethodsWe calculated and compared 10-year CVD (or coronary heart disease (CHD)) risk for 14,772 adults from thirteen cross-sectional South African populations (data collected from 1987 to 2009). Risk characterization performance for the non-laboratory-based score was assessed by comparing rankings of risk with six laboratory-based scores (three versions of Framingham risk, SCORE for high- and low-risk countries, and CUORE) using Spearman rank correlation and percent of population equivalently characterized as ‘high’ or ‘low’ risk. Total 10-year non-laboratory-based risk of CVD death was also calculated for a representative cross-section from the 1998 South African Demographic Health Survey (DHS, n = 9,379) to estimate the national burden of CVD mortality risk.ResultsSpearman correlation coefficients for the non-laboratory-based score with the laboratory-based scores ranged from 0.88 to 0.986. Using conventional thresholds for CVD risk (10% to 20% 10-year CVD risk), 90% to 92% of men and 94% to 97% of women were equivalently characterized as ‘high’ or ‘low’ risk using the non-laboratory-based and Framingham (2008) CVD risk score. These results were robust across the six risk scores evaluated and the thirteen cross-sectional datasets, with few exceptions (lower agreement between the non-laboratory-based and Framingham (1991) CHD risk scores). Approximately 18% of adults in the DHS population were characterized as ‘high CVD risk’ (10-year CVD death risk >20%) using the non-laboratory-based score.ConclusionsWe found a high level of correlation between a simple, non-laboratory-based CVD risk score and commonly-used laboratory-based risk scores. The burden of CVD mortality risk was high for men and women in South Africa. The policy and clinical implications are that fast, low-cost screening tools can lead to similar risk assessment results compared to time- and resource-intensive approaches. Until setting-specific cohort studies can derive and validate country-specific risk scores, non-laboratory-based CVD risk assessment could be an effective and efficient primary CVD screening approach in South Africa.

In humans and other multicellular organisms that have an extended lifespan, the leading causes of death are atherosclerotic cardiovascular disease and cancer. Experimental and clinical evidence indicates that these age-related disorders are linked through dysregulation of telomere homeostasis. Telomeres are DNA protein structures located at the terminal end of chromosomes and shorten with each cycle of cell replication, thereby reflecting the biological age of an organism. Critically shortened telomeres provoke cellular senescence and apoptosis, impairing the function and viability of a cell. The endothelial cells within atherosclerotic plaques have been shown to display features of cellular senescence. Studies have consistently demonstrated an association between shortened telomere length and coronary artery disease (CAD).Several of the CAD risk factors and particularly type 2 diabetes are linked to telomere shortening and cellular senescence. Our interest in telomere biology was prompted by the high incidence of premature CAD and diabetes in a subset of our population, and the hypothesis that these conditions are premature-ageing syndromes. The assessment of telomere length may serve as a better predictor of cardiovascular risk and mortality than currently available risk markers, and anti-senescence therapy targeting the telomere complex is emerging as a new strategy in the treatment of atherosclerosis. We review the evidence linking telomere biology to atherosclerosis and discuss methods to preserve telomere length.

Aims Smoking is a major preventable risk factor for cardiovascular disease and mortality. However, the ‘smoker’s paradox’ suggests that it is associated with better survival after acute myocardial infarction. We aimed to investigate the impact of smoking on mortality and cardiovascular outcomes in patients with stable coronary artery disease. Methods The international CLARIFY registry included 32,703 patients with stable coronary artery disease between 2009 and 2010. Among the 32,378 patients included in the present analysis, Cox proportional hazards models (adjusted for age, sex, geographic region, prior myocardial infarction, and revascularization status) were used to estimate associations between smoking status and outcomes. Patients were stratified as follows: 41.3% of patients never smoked, 12.5% were current smokers and 46.2% were former smokers. Results Current smokers were younger than never-smokers and former smokers (59 vs. 66 and 64 years old, respectively, p < 0.0001). There were more men among current or former smokers compared with never-smokers. Compared with never-smokers, both current and former smokers were at higher risk of all-cause death (hazard ratio = 1.96 and 1.37) and cardiovascular death (hazard ratio = 1.92 and 1.38) within five years (all p < 0.05). Similarly graded and increased risks were present for myocardial infarction and the composite of cardiovascular death, myocardial infarction and stroke (all p < 0.05). Conclusion In contrast to the ‘smoker’s paradox’, current smokers with stable coronary artery disease have a greatly increased risk of future cardiovascular events, including mortality, compared with never-smokers. In former smokers, cardiovascular risk remains elevated albeit at an intermediate level between that of current and never-smokers, reinforcing the importance of smoking cessation. (ISRCTN43070564).

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BackgroundThe relationship between myocardial perfusion imaging (MPI) abnormalities, diabetes mellitus, and glucose control in South African populations is unknown. It was hypothesized that in subjects undergoing MPI for suspected coronary artery disease (CAD), those with diabetes would have more extensive perfusion defects and that diabetes control would influence MPI abnormalities. The aim of this study was to examine the relationship between the severity of CAD diagnosed with MPI in subjects with and without diabetes and to determine the relationship between diabetes control and extent of CAD.MethodsThis study was a retrospective chart review of 340 subjects in whom MPI scans were performed over a 12-month period.ResultsSubjects with diabetes had a higher prevalence of abnormal MPI, with more extensive ischemia, compared with subjects without diabetes (85.6% versus 68%; odds ratio 2.81, P<0.01). Glycated hemoglobin ≥7.0% was associated with a higher risk of abnormal MPI, with more extensive ischemia, compared with subjects having diabetes and glycated hemoglobin <7.0% (odds ratio 2.46, P=0.03) and those without diabetes (odds ratio 4.55, P=0.0001).ConclusionSubjects with diabetes have more extensive myocardial ischemia when compared with subjects without diabetes. Furthermore, poorer diabetes control is associated with more abnormalities on MPI scanning.