Reduction of cardiovascular risk and mortality: a population-based approach

Orthostatic hypotension does not increase cardiovascular risk in the elderly at a population level

BACKGROUND

The general belief that orthostatic hypotension (OH) predisposes to cardiovascular events is based on sparse and contradictory data, rarely derived from population studies.

METHODS

A total of 1,016 men and women aged ≥65 years was studied in a 12-year epidemiological population-based study. Cardiovascular events were detected in subjects with and without OH (blood pressure (BP) decrease ≥20mm Hg for systolic or ≥10mm Hg for diastolic), and Cox analysis was performed including OH as an independent variable.

RESULTS

In univariate analysis, coronary (20.2% vs. 13.1%, P = 0.05), cerebrovascular (13.1% vs. 8.4%, P = 0.05), and heart failure (HF) events (20.2% vs. 13.8%, P = 0.03) were apparently more incidental in subjects with OH than in those without OH. Nevertheless, after adjusting for age, gender, and systolic BP as confounders, OH did not act as a cardiovascular predictor (relative risk for cerebrovascular events 1.33, 95% confidence interval (CI), 0.78-2.2, for coronary events 1.25, CI 0.82-1.88, for HF 1.07, CI 0.71-1.62, for arrhythmias 0.82, CI 0.40-1.37, and for syncope 0.58, CI 0.13-2.71).

CONCLUSIONS

Although OH seems to be a predictor of coronary, cerebrovascular, and HF events, no predictive role was found in models that include biological confounders. Independent of the cause of OH, age and systolic BP, which are positively associated with OH, fully explain the greater incidence of cardiovascular events and the greater cardiovascular risk observed in subjects with OH.

The C825T GNB3 polymorphism, independent of blood pressure, predicts cerebrovascular risk at a population level

BACKGROUND

The role of C825T polymorphism of the candidate GNB3 gene in predicting cerebrovascular outcome has been poorly explored in longitudinal setting at a population level.

METHODS

In an epidemiological setting, 1,678 men and women from general population were genotyped for C825T polymorphism of GNB3 gene and follow-up for 10 years to detect nonfatal and fatal cerebrovascular events (CE). Established cerebrovascular risk factors were used to adjust the multivariate Cox analysis for confounders.

RESULTS

Seventy-three nonfatal and 30 fatal CE were recorded. Incidence of CE was higher in TT than in C-carriers (fatal: 2.6 vs. 1.7%, P < 0.03; nonfatal: 7.8 vs. 3.9%, P < 0.03; fatal recurrences: 1.6 vs. 0.6%, P < 0.03). In Cox analysis, the TT genotype predicted nonfatal (hazard ratio 1.99, 95% confidence interval 1.05-3.79, P = 0.03), fatal (2.91, 1.05-8.12, P = 0.04), and fatal recurrent CE (6.82, 1.50-31.1, P = 0.02) also after adjustment for age, gender, systolic and diastolic blood pressure, body adiposity, atherogenetic blood lipids, serum uric acid, diabetes, calories, caffeine and ethanol intake, and coronary events at baseline. Further adjustment for historical CE made the association between TT genotype and incident fatal CE nonsignificant (hazard ratio 2.72, 95% confidence interval 0.96-7.22, P = 0.06).

CONCLUSIONS

The TT genotype of GNB3 gene predicts incident CE independent of blood pressure and other established risk factors at a population level. Further studies are needed to clarify the nature and pathways of this association.

The risk of subsequent cancer and arterial cardiovascular events in patients with superficial vein thrombosis in the legs

Although it has been clearly demonstrated that venous thromboembolism is associated with an increased risk of subsequent overt cancer and arterial cardiovascular events in comparison with control populations, whether this association also applies to patients with isolated (ie, without concomitant involvement of the deep vein system) superficial vein thrombosis (SVT) in the legs is unknown. In 737 consecutive patients with isolated SVT not involving the sapheno-femoral junction, we conducted a retrospective investigation to assess the rate of cancer and that of arterial cardiovascular events occurring during follow-up. The event rates were compared with those occurring in 1438 controls having comparable characteristics. Both cases and controls were followed-up for an average period of 26 ± 8 months (range, 3-45). Malignancy was diagnosed in 26 cases (3.5%) and 56 controls (3.9%), leading to a hazard ratio of 0.86 (95% confidence interval, 0.55%-1.35%). Arterial cardiovascular events occurred in 32 cases (4.3%) and 63 controls (4.4%), leading to a hazard ratio of 0.97 (95% confidence interval, 0.63%-1.50%). We conclude that the occurrence of isolated SVT in the legs does not place patients at an increased risk of malignancies or arterial cardiovascular events. Whether this conclusion also applies to patients whose thrombosis involves the sapheno-femoral junction remains to be demonstrated.

Glycaemic fall after a glucose load. A population-based study

BACKGROUND AND AIMS

A blood glucose (BG) fall after an oral glucose load has never been described previously at a population level. This study was aimed at looking for a plasma glucose trend after an oral glucose load for possible blood glucose fall if any, and for its impact on coronary mortality at a population level.

METHODS AND RESULTS

In subjects from an unselected general population, BG and insulin were detected before and 1 and 2h after a 75-g oral glucose load for insulin sensitivity and β-cell function determination. Blood pressure, blood examinations and left ventricular mass were measured, and mortality was monitored for 18.8±7.7 years. According to discriminant analysis, the population was stratified into cluster 0 (1-h BG < fasting BG; n=497) and cluster 1 (1-h BG ≥ fasting BG; n=1733). To avoid any interference of age and sex, statistical analysis was limited to two age-gender-matched cohorts of 490 subjects from each cluster (n=940). Subjects in cluster 0 showed significantly higher insulin sensitivity and β-cell function, lower visceral adiposity and lower blood pressure values. Adjusted coronary mortality was 8 times lower in cluster 0 than 1 (p<0.001). The relative risk of belonging to cluster 1 was 5.40 (95% CI 2.22-13.1).

CONCLUSION

It seems that two clusters exist in the general population with respect to their response to an oral glucose load, independent of age and gender. Subjects who respond with a BG decrease could represent a privileged sub-population, where insulin sensitivity and β-cell function are better, some risk factors are less prevalent, and coronary mortality is lower.

Hypertension in the elderly and the very old

High systolic blood pressure represents a challenge for the modern world. Epidemiologists are in the best position to appreciate the importance of systolic hypertension and its cardiovascular consequences. Although the label of hypertension seems to have lower importance in the elderly, and above all in the very old, than in younger people, high systolic and high pulse pressure are risk factors for cardiovascular events and necessitates treatment. Unfortunately, due to indolence and lack of aggressiveness, only a limited fraction of elderly hypertensive patients receives adequate therapy.

Electrocardiographic criteria of left ventricular hypertrophy in general population

The question on whether the electrocardiographic criteria are reliable for detection of left ventricular hypertrophy (LVH) and play a role in predicting outcome is open. Answer can only proceed from population-based studies over unselected people followed up for years. In this study, 1,699 subjects from general population underwent echocardiogram and standard electrocardiogram (ECG) codified for LVH with Minnesota code and with other five methods. Other items were also recorded and used as covariables. Left ventricular mass index (LVMI) was 127.6 +/- 44.9 g m(-2) in men and 120.8 +/- 41.2 g m(-2 )in women, and correlated directly with age in both genders. Prevalence of echocardiographic LVH was 36.6% in men and 53.4% in women. LVMI correlated directly with the Sokolow-Lyon score in both genders at any age, with the Romhilt-Estes, Cornell and R(aVL) scores in all subjects but elderly men, and with the Lewis score in men and women aged < or =69 years. Sensitivity and the predictive value of electrocardiographic tests, as well as the prevalence of LVH diagnosed with electrocardiographic criteria, were always low. Specificity was high for all the tests, and in particular for the Cornell index. Only when diagnosed with echocardiogram or with the Sokolow-Lyon criterion, LVH was an independent predictor of mortality. We conclude that electrocardiographic tests cannot be used as a surrogate of echocardiogram in detecting LVH in the general population because their positive predictive value (PPV) is unacceptably low. On the contrary, they could replace echocardiography in the follow up and for prediction of outcome, when LVH has previously been correctly diagnosed with other methods.