Hypoparathyroidism potentiates cardiovascular complications through disturbed calcium metabolism: possible risk of vitamin D(3) analog administration in dialysis patients with end-stage renal disease.
OBJECTIVE
Progressive cardiovascular calcification in dialysis patients with end-stage renal disease (ESRD) is a serious complication; however, the precise mechanism remains uncertain. We tested whether metabolic calcium abnormalities and hypoparathyroidism might have a correlation with cardiovascular complications in ESRD patients.


METHODS
A series of 48 ESRD patients with cardiovascular diseases and/or congestive heart failure, aged 36-82 (61 +/- 12) years, 23 male and 25 female, were enrolled in this study. Serum total calcium (Ca, mmol/l), inorganic phosphate (mmol/l), and intact parathyroid hormone (iPTH, pg/ml) levels were determined in all cases.


RESULTS
Organic heart disease was confirmed in 28 patients (58.3%), including 15 with coronary artery disease: 8 with aortic aneurysm, 8 with stenotic valvular heart disease, 9 with excessive mitral annular calcification, 3 with dialysis cardiomyopathy, and 7 with obstructive arterial disease. Serum iPTH measurement revealed hypoparathyroidism (iPTH <60) in 20 of 48 (41.7%) and hyperthyroidism (iPTH >/=200) in 13 of 48 (27.1%) subjects. The 20 patients with low iPTH had a higher prevalence of valvular heart disease, a higher total Ca level corrected for serum albumin (2.70 +/- 0.30 in low iPTH vs. 2.47 +/- 0.30 in normal iPTH, 2.35 +/- 0.20 in high iPTH, p = 0.003) and a higher tendency of vitamin D(3) analog use (65% in low iPTH vs. 33% in normal iPTH and 46% in high iPTH, p = 0.078). Moreover, corrected serum Ca exhibited a negative logarithmic correlation with serum iPTH: corrected Ca = -0.284x log (iPTH) + 3.021 (r = 0.637, p = 0.0001). Multiple logistic regression analysis revealed diabetes and hypoparathyroidism (iPTH <60) as risk factors for cardiovascular complications in ESRD.


CONCLUSIONS
These results suggest that hypercalcemia and hypoparathyroidism in conjunction with vitamin D(3) use might play an important role in cardiovascular complications of chronic dialysis patients.
Tsuchihashi
K
K
2nd Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan. tsuchiha@sapmed.ac.jp
Takizawa
H
H
Torii
T
T
Ikeda
R
R
Nakahara
N
N
Yuda
S
S
Kobayashi
N
N
Nakata
T
T
Ura
N
N
Shimamoto
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002114:Calcinosis / Q000209:etiology / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000209:etiology* / Q000378:metabolism; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000009:adverse effects*; D006934:Hypercalcemia / Q000150:complications / Q000209:etiology; D007011:Hypoparathyroidism / Q000150:complications* / Q000209:etiology / Q000378:metabolism; D007676:Kidney Failure, Chronic / Q000150:complications* / Q000378:metabolism / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010531:Peritoneal Dialysis, Continuous Ambulatory / Q000009:adverse effects; D006435:Renal Dialysis / Q000009:adverse effects
D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D002118:Calcium; C008088:alfacalcidol