Copeptin, the C-terminal part of arginine-vasopressin, is increased in hypertensive adolescents and closely associated with metabolic syndrome (MS). We aimed to investigate whether serum copeptin can be used to differentiate masked hypertension (MHT) and MS, and the role of sodium intake, natriuretic peptide response and renin-angiotensin-aldosterone system in MHT and MS in obese youth.
Obese children aged 10-18 years with normal office blood pressure measurements were included. Patients with MHT and normotension and those with MS and non-MS were evaluated separately. Biochemical parameters, copeptin, brain natriuretic peptide (BNP), aldosterone, renin, urine sodium, and protein were evaluated. Echocardiography, fundoscopic examination, and ambulatory blood pressure monitoring were performed.
There were 80 (M/F=39/41) obese patients with a mean age of 13.78 ± 1.93 years. The cases with MHT, MS, and concomitant MHT and MS were 53,24, and 13%, respectively. Copeptin levels were similar among patients with and without MHT or MS (p>0.05). However, multivariate analysis revealed that copeptin significantly increased the probability of MHT (OR 1.01, 95% CI=1.001-1.018, p=0.033). Copeptin was positively correlated with daytime systolic and diastolic load, aldosterone, BNP, and urine microalbumin/creatinine levels (p<0.05). Linear regression analyses revealed that copeptin was significantly correlated with BNP regardless of having MHT or MS in obese youth. In the MHT group, 24-h sodium excretion was not significantly correlated with BNP.
Copeptin may be a beneficial biomarker to discriminate MHT, but not MS in obese children and adolescents. An insufficient BNP response to sodium intake might be one of the underlying causes of MHT in obese cases.