Table 1.

Baseline characteristics of the cohort by dialysate calcium assignment

Variable<2.5 meq/L (n=159)2.5 meq/L (n=1550)>2.5 meq/L (n=361)P Value
Demographic variables
 Age at index or event date (median, Q1, Q3)62.0 (53.0, 69.0)66.0 (57.0, 76.0)64.0 (53.0, 75.0)0.002
 Dialysis vintage in yr (median, Q1, Q3)4.5 (2.2, 7.6)2.4 (1.0, 5.2)3.0 (1.1, 6.8)<0.001
 Black (%)52.837.242.7<0.001
 Male (%)45.352.553.20.20
 CAD22.032.632.10.02
 CHF (%)27.035.030.20.13
 Diabetes (%)48.456.650.70.18
 Hypertension (%)93.787.085.60.04
 Arrhythmia (%)13.212.112.20.91
 Hyperlipidemia10.17.05.00.12
 PVD15.119.518.60.05
 Smoker4.43.54.20.17
 Valvular heart disease (%)2.51.11.10.06
Medications prescribed at time of event (%)
 ACEi or ARB59.546.348.60.003
 Antiarrhythmic medication16.516.314.80.39
 BBL53.852.545.30.71
 QT-prolonging medication51.944.946.10.26
 Calcium supplement medication34.842.538.80.12
 Vitamin D80.772.868.10.003
Last recorded laboratory values (median value, Q1, Q3)
 Hemoglobin (g/dl)11.8 (10.8, 12.4)11.7 (10.9, 12.6)11.8 (10.8, 12.6)0.64
 Potassium (meq/L)4.6 (4.0, 5.1)4.7 (4.2, 5.3)4.7 (4.1, 5.3)0.15
 Phosphorus (meq/L)5.5 (4.6, 6.4)5.1 (4.1, 6.3)4.9 (4.0, 6.1)0.05
 Creatinine (mg/dl)8.4 (6.2, 9.7)7.4 (5.7, 9.6)8.0 (6.1, 10.1)0.06
 Bicarbonate (meq/L)22 (20, 26)22 (19, 25)21.0 (18.0, 24.0)0.01
 URR70.9 (66.0, 75.0)72.0 (67.0, 75.9)72.0 (68.0, 75.9)0.28
 Albumin (g/L)3.8 (3.3, 4.1)3.7 (3.3, 4.0)3.7 (3.4, 4.0)0.05
 Corrected serum calcium (mg/dl)10.1 (9.4, 10.7)9.5 (9.0, 10.0)9.2 (8.8, 9.8)<0.001
Dialysis prescription parameters
 Potassium dialysate assignment (%; Meq/L)0.21
  <2.08.912.87.2
  2.076.666.672.1
  >2.014.620.620.6
 Calcium gradient (median, Q1, Q3)3.0 (2.7, 3.4)2.3 (2.0, 2.5)1.7 (1.4, 2.0)<0.001
 Fluid removed % DW mean 90 (median, Q1, Q3)3.5 (2.8, 4.3)3.5 (2.7, 4.4)3.7 (2.8, 4.7)0.88
 Dialysis BP (mmHg)
  Predialysis BP144/79144/77142/77
  Postdialysis BP134/72136/73138/75
  Intradialytic fall in mean arterial BP (median, IQR)7 (−6, 23)2 (−6, 21)0 (−7, 16)0.004
  • Q, quartile; CAD, coronary artery disease; CHF, congestive heart failure; PVD, peripheral vascular disease; ACEi/ARB, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker; BBL, β-blocker; URR, urea reduction ratio; DW, dry weight; IQR, interquartile range.