Objectives: Twenty-four-hour ambulatory blood pressure (BP) data and the presence of metabolic syndrome (MS) are both good discriminators of cardiovascular risk. We examined the relationship between metabolic syndrome scores as defined by the International Diabetes Federation 2005 report (IDF-2005) and 24h ambulatory BP data in newly diagnosed hypertensives.
Methods: We evaluated 352 non-diabetic subjects (male/female: 167/185, aged 49+/-13). Based on IDF-2005 criteria, 212 subjects fulfilled 0, 1 or 2 criteria (no metabolic syndrome) and 140 fulfilled 3, 4 or 5 criteria (metabolic syndrome). Patients were divided into two groups (MS and non-MS), matched for age and casual BP All underwent 24h ambulatory blood pressure monitoring.
Results: No significant differences were found between non-MS and MS for casual BP (153/92+/-17/8 vs. 154/92+/-16/8 mmHg), age (48+/-14 vs. 50+/-12 years), 24h ambulatory BP (131/82+/-14/10 vs. 133/82+/-14/9 mmHg), daytime BP (135/86+/-14/11 vs. 137/85+/-14/9 mmHg), nighttime BP (122/74+/-15/11 vs. 124/74+/-15/10 mmHg), nighttime fall (9+/-6 vs. 9+/-6 %), BP on arising (131/82+/-20/15 vs. 135/82+/-21/15 mmHg), evening surge (7+/-14 vs. 10+/-15 mmHg), percentage of dippers (42.5 vs. 37.1%) or percentage of non-dippers (50.9 vs. 50.7%). However, significant differences between non-MS and MS were found for morning BP surge (25+/-12 vs. 28+/-15 mmHg, p<0.03). Also, when patients were divided into four groups according to MS scores (0/1, 2, 3 or 4/5), significant differences between groups were observed only for BP on arising (group 2 vs. 4/5, 132/79+/-21/15 vs. 140/84+/-10/15 mmHg, p<0.05; group 3 vs. 4/5, 131/81+/-20/15 vs. 140/84+/-20/15, p<0.005) and for morning BP surge (group 0/1 vs. 4/5, 24+/-11 vs. 29+/-15 mmHg, p<0.003).
Conclusions: We conclude that in newly diagnosed hypertensive subjects there is no significant relationship between the severity of metabolic syndrome and ambulatory blood pressure data or circadian variations. The only exception found was a greater morning BP surge in patients with MS, whose importance as a determinant of cardiovascular risk needs to be clarified by further studies.