SERUM PHOSPHATE IN WHITE COAT HYPERTENSIVE PATIENTS: FOCUS ON DIPPING STATUS AND METABOLIC SYNDROME: 5B.05

Abstract

Objective: Recent studies indicate an association of serum phosphate levels with blood pressure in hypertensive patients. A growing body of evidence suggests that white coat hypertension (WCH) is associated with target organ damage. Furthermore, metabolic syndrome (MS) and non-dipping pattern are also associated with increased cardiovascular risk. The purpose of this study was to explore the nocturnal blood pressure fall in WCH patients according to their serum phosphate, calcium levels and MS components. Design and Methods: The study comprised 2600 patients with WCH who attended our outpatient clinics. All patients underwent repeated office blood pressure measurements, 24-h ambulatory blood pressure monitoring, full clinical and laboratory evaluation. The diagnosis of MS was made according to the Adult Treatment Panel III criteria. Dipping pattern was defined as ‘dippers’ with nocturnal systolic blood pressure (NSBP) fall greater than or equal to 10% but less than 20%,‘non-dippers’ with NSBP fall greater than or equal to 0% but less than 10%, ‘extreme dippers’ with NSBP fall greater than or equal to 20%, and ‘reverse dippers’ with NSBP increase. Results: ‘Extreme dippers’ were 413, ‘dippers’ 1337, ‘non-dippers’ 734 and ‘reverse dippers’ 116. ‘Reverse dippers’ presented with significantly lower levels of serum phosphate, while ‘extreme dippers’ had significantly higher levels (3.39 ± 3.29 vs 3.58 ± 3.52 mg/dl, p < 0.0001). Grouping the patients according to the number of MS components, the main observation was the inverse relationship of serum phosphate to MS components (3.53 ± 0.36 to 3.50 ± 0.38 to 3.49 ± 0.38 to 3.44 ± 0.36 to 3.35 ± 0.31 mg/dl, p = 0.003). Conclusions: WCH patients with low phosphate levels appear to have impaired metabolic profile and higher incidence of non dipping profile. This observation may be important for the stratification of cardiovascular risk in WCH patients.