Copyright  © 2000 Medicina On line - Revista Virtual de Medicina
Volume 1- Número 2 - Ano I (Abr/Mai/Jun de 1998)
HORMONAL RESPONSES TO ORAL PHOSPHORUS (P) SUPPLEMENTATION IN PRE-DIALYSIS PATIENTS (PRD) WITH LOW LEVELS OF PTH OR ADYNAMIC BONE DISEASE (ABD).
L.Cuppari, A.Carvalho, R.Lobão, R.Ventura, L.Martini, J.G. Vieira ,S.A.Draibe.
Nephrology Division, Universidade Federal de São Paulo, Brazil.
Normal to low serum P, low PTH and normal to high levels of calcitriol are frequently seen in our PRD patients with ABD. In order to test the hypothesis that the observed low P intake could contribute to this condition, 18 PRD  patients with  iPTH level menor ou igual a 40 pg/ml and serum P menor ou igual 4.5 mg/dl  (n=7) or with ABD (bone biopsy;n=11) were studied.

They were:

  • 13M/5F;
  • age=66.5 (35 - 78) years;
  • creatinine=2,2 (1.0 -3.5) mg/dl;
  • body mass index=26.2 (18-33)kg/m2 ; [median(range)].
Initially,  they received 0.5 g/d of oral P (as neutral complex) for one month and then 1g/d for another month. Serum ionized calcium (iCa), iPTH, P, calcitriol (1,25), and urinary P(UP) were measured pre and at the end of  each period. 

Results:

     
     iPTH
    (pg/ml)    		 P
    (mg/dl)    		 iCa
    (mmol/l)    		 UP
    (mg/24 hs)    		 1,25
    (pg/ml)
    Pre  58.5
    (8-266)    		 3.25
    (2.2-4.4)    		 1.26
    (1.13-1.38)    		 486
    (254-2131)    		 34.5
    (19.0-74.0)
    0.5 g  P 50.5
    (2.5-164)    		 3.50
    (2.7-4.6)    		 1.25
    (1.16-1.32)    		 774 *
    (396-1241)
    1 g P 83.0*
    (27-324)    		 3.55
    (2.3-5.7)    		 1.19*
    (1.10-1.31)    		 1061*
    (553-1281)    		 24.9*
    (16.9-93.4)


* p<0.05 as compared to pre 

Before supplementation, P and protein intakes and protein catabolic rate  were 593 (373-1237) mg/d ,0.79 (0.57-1.31)g/kg/d, and 1.03 (0.57-1.37) g/kg/d respectively. Only one patient had signs of malnutrition. Pre supplementation iPTH correlated with PCR (r=0.56), calcitriol correlated negatively with iCa (r=-0.47) and with P (r=-0.53; p<0.05). Serum creatinine did not change. Fifteen patients (83%) experienced an increase in iPTH. The per cent iPTH changes correlated  negatively with basal iPTH (r= -0.62;p<0.01).

Although 1,25 levels decreased significantly they remained within the normal range.This study shows that oral P supplementation reverses the relative hypoparathyroidism observed in our PRD patients. Thus this treatment could contribute to improve the low bone turnover of ABD patients.