Relation between serum calcium, phosphate, parathyroid hormone and 'nondipper' circadian blood pressure variability profile in patients with normal renal function.
OBJECTIVE
In patients with renal disease, an association between abnormal circadian blood pressure profile and abnormalities in bone and mineral metabolism, including vascular calcifications, is well known. However, such a link has not yet been reported in hypertensive patients with normal renal function. We aimed to evaluate if higher serum phosphate, calcium, parathyroid hormone (PTH) level and the calcium x phosphate (Ca x P) product would be associated with a nondipper hypertension, in patients with normal renal function and without any PTH disorder.


METHODS
190 hypertensive subjects with the following inclusion criteria were enrolled: (1) normal phosphate and PTH levels; (2) glomerular filtration rate (GFR) >60 ml/min, and (3) no history of calcium, phosphate, vitamin D medication and hyperparathyroidism.


RESULTS
Of the total population, 76 patients (40%) were classified as dippers and 114 (60%) as nondippers. Nondipper patients had higher levels of phosphate (3.70 +/- 0.61 vs. 3.35 +/- 0.44 mg/dl, p = 0.001), Ca x P product (35.4 +/- 6.5 vs. 31.5 +/- 5.0, p = 0.001) and PTH (75.7 +/- 28.8 vs. 46.6 +/- 17.1 pg/ml, p = 0.000) compared to dipper patients. Independent predictors (multiple regression) for nondipper hypertension were PTH (beta = 0.43, p = 0.001) and phosphate (beta = 0.9, p = 0.03).


CONCLUSIONS
We demonstrate a graded independent relation between higher levels of phosphate, PTH, Ca x P product and the risk of nondipping in hypertensive patients with an estimated GFR of >60 ml/min and normal mineral metabolism.
Kanbay
Mehmet
M
Department of Internal Medicine, Section of Nephrology, Fatih University Faculty of Medicine, Ankara, Turkey. mkanbay@fatih.edu.tr
Isik
Bunyamin
B
Akcay
Ali
A
Ozkara
Adem
A
Karakurt
Feridun
F
Turgut
Faruk
F
Alkan
Rabia
R
Uz
Ebru
E
Bavbek
Nuket
N
Yigitoglu
Ramazan
R
Covic
Adrian
A
D000328:Adult; D000368:Aged; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D002118:Calcium / Q000097:blood*; D002940:Circadian Rhythm; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology*; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010710:Phosphates / Q000097:blood*
C470125:PTH protein, human; D010281:Parathyroid Hormone; D010710:Phosphates; D002118:Calcium