A decrease in intact parathyroid hormone (iPTH) levels is associated with higher mortality in prevalent hemodialysis patients.
BACKGROUND
The mortality of dialysis patients is 10- to 100-fold higher than in the general population. Baseline serum PTH levels, and more recently, changes in serum PTH levels (ΔPTH) over time, have been associated to mortality in dialysis patients.


METHODS
We explored the relationship between ΔPTH over 1 year with mortality over the next year in a prospective cohort of 115 prevalent hemodialysis patients from a single center that had median baseline iPTH levels within guideline recommendations.


RESULTS
Median baseline iPTH levels were 205 (116.5, 400) pg/ml. ΔiPTH between baseline and 1 year was 85.2 ± 57.1 pg/ml. During the second year of follow-up, 27 patients died. ΔiPTH was significantly higher in patients who survived (+157.30 ± 25.82 pg/ml) than in those who died (+39.03 ± 60.95 pg/ml), while baseline iPTH values were not significantly different. The highest mortality (48%) was observed in patients with a decrease in ΔiPTH (ΔiPTH quartile 1, negative ΔiPTH) and the lowest (12%) mortality in quartile 3 ΔiPTH (ΔiPTH increase 101-300 pg/ml). In a logistic regression model, ΔiPTH was associated with mortality with an odds ratio (OR) of 0.998 (95% CI 0.996-0999, p = 0.038). In multivariable analysis, mortality risk was 73% and 88% lower for patients with ΔiPTH 0-100 pg/ml and 101-300 pg/ml, respectively, than for those with a decrease in ΔiPTH. In patients with a decrease in ΔiPTH, the OR for death was 4.131 (1.515-11.27)(p = 0.006).


CONCLUSIONS
In prevalent hemodialysis patients with median baseline iPTH values within the guideline recommended range, a decrease in ΔiPTH was associated with higher mortality. Further studies are required to understand the mechanisms and therapeutic implications of this observation that challenges current clinical practice.
Servicio de Nefrología, Fundación Jiménez Díaz, Madrid, España.|Fundación Instituto de Investigación Sanitaria, Fundación Jiménez Díaz (IIS-FJD), Madrid, España.|Spanish Biomedical Research Network in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain.
Ricardo
R
Villa-Bellosta
Servicio de Nefrología, Fundación Jiménez Díaz, Madrid, España.|Fundación Instituto de Investigación Sanitaria, Fundación Jiménez Díaz (IIS-FJD), Madrid, España.|Spanish Kidney Research Network (REDINREN), Madrid, Spain.
Laura
L
Rodriguez-Osorio
Servicio de Nefrología, Fundación Jiménez Díaz, Madrid, España.|Fundación Instituto de Investigación Sanitaria, Fundación Jiménez Díaz (IIS-FJD), Madrid, España.|Spanish Biomedical Research Network in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain.
Sebastian
S
Mas
Servicio de Nefrología, Fundación Jiménez Díaz, Madrid, España.
Younes
Y
Abadi
Servicio de Laboratorio de Bioquímica, Fundación Jiménez Díaz, Madrid, España.
Mercedes
M
Rubert
Servicio de Laboratorio de Bioquímica, Fundación Jiménez Díaz, Madrid, España.
Concepción
C
de la Piedra
Servicio de Nefrología, Fundación Jiménez Díaz, Madrid, España.|Fundación Instituto de Investigación Sanitaria, Fundación Jiménez Díaz (IIS-FJD), Madrid, España.
Carolina
C
Gracia-Iguacel
Fundación Instituto de Investigación Sanitaria, Fundación Jiménez Díaz (IIS-FJD), Madrid, España.
Ignacio
I
Mahillo
Servicio de Nefrología, Fundación Jiménez Díaz, Madrid, España.|Fundación Instituto de Investigación Sanitaria, Fundación Jiménez Díaz (IIS-FJD), Madrid, España.|Spanish Kidney Research Network (REDINREN), Madrid, Spain.|Universidad Autónoma de Madrid, Madrid, España.
Alberto
A
Ortiz
Servicio de Nefrología, Fundación Jiménez Díaz, Madrid, España.|Fundación Instituto de Investigación Sanitaria, Fundación Jiménez Díaz (IIS-FJD), Madrid, España.|Spanish Biomedical Research Network in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain.|Universidad Autónoma de Madrid, Madrid, España.
Jesús
J
Egido
Servicio de Nefrología, Fundación Jiménez Díaz, Madrid, España.|Fundación Instituto de Investigación Sanitaria, Fundación Jiménez Díaz (IIS-FJD), Madrid, España.|Spanish Kidney Research Network (REDINREN), Madrid, Spain.|Universidad Autónoma de Madrid, Madrid, España.
Emilio
E
González-Parra
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011379:Prognosis; D011446:Prospective Studies; D006435:Renal Dialysis / Q000401:mortality*
D010281:Parathyroid Hormone