Hypoparathyroidism potentiates cardiovascular complications through disturbed calcium metabolism: Possible risk of vitamin D-3 analog administration in dialysis patients with end-stage renal disease

Progressive cardiovascular calcification in dialysis patients with end-stag e renal disease (ESRD) is a serious complication; however, the precise mech anism remains uncertain. We tested whether metabolic calcium abnormalities and hypoparathyroidism might have a correlation with cardiovascular complic ations in ESRD patients. Methods: A series of 48 ESRD patients with cardiov ascular diseases and/or congestive heartfailure, aged 36-82(61 +/- 12) year s, 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 d isease was confirmed in 28 patients (58.3%), including 15 with coronary art ery disease: 8 with aortic aneurysm, 8 with stenotic valvular heart disease , 9 with excessive mitral annular calcification, 3 with dialysis cardiomyop athy, and 7 with obstructive arterial disease. Serum IPTH measurement revea led hypoparathyroidism (IPTH <60) in 20 of 48 (41.7%) and hyperthyroidism ( IPTH greater than or equal to 200) in 13 of 48 (27.1%) subjects. The 20 pat ients with low IPTH had a higher prevalence of valvular heart disease, a hi gher 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) an d a higher tendency of vitamin D-3 analog use (65% in low IPTH vs. 33% in n ormal IPTH and 46% in high IPTH, p = 0.078). Moreover, corrected serum Ca e xhibited a negative logarithmic correlation with serum iPTH: corrected Ca = -0.284 x log (IPTH) + 3.021 (r = 0.637, p = 0.0001). Multiple logistic reg ression analysis revealed diabetes and hypoparathyroidism (IPTH <60) as ris k factors for cardiovascular complications in ESRD. Conclusion: These resul ts suggest that hypercalcemia and hypoparathyroidism in conjunction with vi tamin use D-3 might play an important role in cardiovascular complications of chronic dialysis patients. Copyright (C) 2000 S. Karger AG, Basel.