The effect of nondipper blood pressure pattern on target organ damage in patients with metabolic syndrome

Objectives: Both metabolic syndrome (MetS) and nondipping status (insufficient reduction in nocturnal blood pressure) have been linked with target organ damage. We evaluated the effect of nondipping status on target organ damage in subjects with MetS. Study design: Eighty-two patients diagnosed as having MetS were divided into two groups according to the findings of 24hour ambulatory blood pressure monitoring as dipper (n=35, 19 women, 16 men; mean age 48.4 +/- 6.4 years) and nondipper (n=47, 35 women, 12 men; mean age 50.4 +/- 4.7 years). Cardiac damage was assessed by conventional and tissue Doppler echocardiography, and renal damage by 24-hour urinary albumin excretion. Results: The two groups were similar with regard to age, body mass index, presence of diabetes, smoking, clinical and 24-hour, daytime and nighttime blood pressures, plasma lipid profile, distribution of and the mean total number of MetS criteria. The ratio of early (Em) to late (Am) left ventricular peak diastolic myocardial velocities (Em/Am) was significantly lower in nondippers (p=0.016). Nondippers also had higher values of left ventricular mass index, myocardial performance index, and 24-hour urinary albumin excretion, but these differences did not reach a significant level (p=0.110, p=0.099, p=0.093, respectively). Multivariate regression analysis showed increasing age and nondipping status as independent factors associated with decreased Em/Am ratio (beta=-0.25, p=0.020 and beta=-0.22, p=0.042, respectively). Conclusion: In subjects with MetS, nondipping status may be associated with both cardiac and renal damage independent of other components of MetS. Since the degree of diastolic dysfunction is more marked than that of albuminuria in nondippers, it may be extrapolated that the extent of cardiac damage surpasses renal damage in these subjects.