The impact of the metabolic syndrome--but not of hypertension--on all-cause mortality disappears in the elderly.

OBJECTIVE: The metabolic syndrome predicts the risk of cardiovascular and all-cause death, but its clinical relevance in the elderly remains debatable. We aimed to determine the impact of the metabolic syndrome on all-cause mortality according to age, in comparison with hypertension alone.
METHODS: We studied 129 655 participants (82 110 men and 47 545 women) undergoing a standard health check-up at the Investigations Préventives et Cliniques center (Paris, France). Mean follow-up was 4.9±2.6 years. The prevalence of the metabolic syndrome and its components was determined according to age group (<55, 55-65, >65 years old). All-cause mortality according to metabolic syndrome and age was determined using Cox regression model analysis, unadjusted or adjusted for age, sex, smoking and other confounding factors.
RESULTS: The prevalence of the metabolic syndrome and all its components except lipid parameters strongly increased with age. All-cause mortality associated with the metabolic syndrome (using three different definitions) was significantly elevated in participants below 55 years old, and was little affected by adjustment for confounding factors. However, it decreased from 1.77 (1.45-2.16) in participants below 55 years old to 1.12 (0.84-1.48) in participants above 65 years old [hazard ratio (95% confidence interval); National Cholesterol Education Program definition]. Waist circumference, fasting blood glucose and lipid parameters failed to predict mortality in participants above 65 years old. In contrast, hypertension (blood pressure>140/90 mmHg or treatment) remained a significant predictor of all-cause mortality [hazard ratio 1.30 (95% confidence interval 1.02-1.66)] in participants above 65 years old.
CONCLUSIONS: In a setting representative of primary care, hypertension but not the metabolic syndrome remains a strong risk factor for all-cause mortality in participants above 65 years old.