Pretreatment plasma intact parathyroid hormone and serum calcium levels, but not serum phosphate levels, predict the response to maxacalcitol therapy in dialysis patients with secondary hyperparathyroidism.
BACKGROUND
The treatment strategy for secondary hyperparathyroidism is generally determined empirically with regards to present parathyroid function and serum calcium (Ca) and inorganic phosphate (Pi) levels. More evidence is needed to avoid the aimless continuation of active vitamin D therapy.


METHODS
Nondiabetic dialysis patients whose plasma intact parathyroid hormone (iPTH) levels were greater than 300 pg/ml were included in the study. Maxacalcitol was intravenously injected three times a week. The treatment was continued for 48 weeks, unless the iPTH level was reduced to less than 300 pg/ml or unfavorable events occurred. The patients whose plasma iPTH levels were below 300 pg/ml within 48 weeks were defined as those who had been successfully treated.


RESULTS
Findings for 146 patients were analyzed, and 96 patients were successfully treated. Serum Pi levels did not significantly increase during the therapy. The pretreatment plasma iPTH levels and serum Ca levels were lower in the patients who were successfully treated with maxacalcitol. A logistic regression study and classifying by stratum analyses revealed that the pretreatment serum Ca levels and plasma iPTH levels were significantly related to the result of maxacalcitol therapy, while the serum Pi levels were not. Analyses using a receiver-operating characteristic curve revealed that the areas under curves obtained for iPTH and Ca were significantly greater than those obtained for Pi (P < 0.0001).


CONCLUSIONS
Serum Ca levels and parathyroid function were correlated with the results of maxacalcitol therapy. Pretreatment serum Pi levels could not predict the result.
Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, 1-751 Asahimachi-dori, Niigata 951-8510, Japan.
Yuko
Y
Oyama
Junichiro James
JJ
Kazama
Kentaro
K
Omori
Noboru
N
Higuchi
Shigemi
S
Kameda
Suguru
S
Yamamoto
Yumi
Y
Ito
Hiroki
H
Maruyama
Ichiei
I
Narita
Fumitake
F
Gejyo
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D002117:Calcitriol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010710:Phosphates / Q000097:blood*; D011237:Predictive Value of Tests; D006435:Renal Dialysis; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D010281:Parathyroid Hormone; D010710:Phosphates; D002117:Calcitriol; C051883:maxacalcitol; D002118:Calcium