Bone metabolism according to chronic kidney disease stages in patients undergoing kidney transplantation: a 5-year database analysis.
BACKGROUND
While kidney transplantation successfully reverses many complications of uremia that are not corrected with dialysis therapy, elevated parathyroid hormone (PTH) levels and other alterations of mineral metabolism persist in transplant recipients.


METHODS
A single-center cohort retrospective database analysis was performed of 497 consecutive adult patients who underwent first kidney transplantation between 1994 and 2004. At 1- and 5-year follow-up, a descriptive analysis was performed of mineral metabolism parameters of chronic kidney disease stage according to NKF KDOQI (National Kidney Foundation Kidney Disease Outcomes Quality Initiative) in patients with a functional graft at 1 year. Glomerular filtration rate was estimated using the abbreviated MDRD (Modification of Diet in Renal Disease) equation.


RESULTS
Most of the transplants (99.2%) were from cadaveric donors. Mean (SD) patient age was 47.7 (13.3) years, and 69% of patients were men. The causes of chronic kidney disease were glomerular (35.4%), congenital (15.4%), systemic (14.1%), vascular (11.3%), interstitial (10.1%), and other (<1%). The percentage of patients in each stage of chronic kidney disease with calcium levels less than 8.5 mg/dL, phosphorus greater than 4.5 mg/dL, and PTHi greater than 150 pg/mL increased as graft function declined. Six posttransplantation parathyroidectomies were performed. Only 130 patients received secondary hyperparathyroidism treatment within 5 years after transplantation: calcium carbonate, 36.9%; calcium acetate, 1.5%; calcium carbonate plus cholecalciferol, 21%; calcitriol, 71%; and calcifediol, 0.8%.


CONCLUSIONS
The prevalence of hypocalcemia, hyperphosphatemia, and elevated PTH level increased with chronic kidney disease stage. Classification of renal transplant recipients by KDOQI stage may enable clinicians to identify patients at increased risk and to target appropriate therapy to improve outcome. There is an opportunity for enhanced management of secondary hyperparathyroidism in these patients.
Fernández-Fresnedo
G
G
Nephrology Service, University Hospital Marqués de Valdecilla. Santander, Cantabria, Spain. nefffg@humv.es
Rodrigo
E
E
Ruiz
J C
JC
Martín de Francisco
A L
AL
Arias
M
M
D000328:Adult; D001842:Bone and Bones / Q000378:metabolism*; D002908:Chronic Disease; D015331:Cohort Studies; D019992:Databases as Topic; D005260:Female; D005500:Follow-Up Studies; D005582:Foundations; D006801:Humans; D007674:Kidney Diseases / Q000097:blood / Q000145:classification / Q000601:surgery; D007676:Kidney Failure, Chronic / Q000378:metabolism* / Q000601:surgery*; D016030:Kidney Transplantation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome