Table 1. Characteristics of Patients in Cohort 1

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Table 1. Characteristics of patients in cohort 1

2003 / 2004 / 2005 / 2006 / 2007 / 2008 / 2009 / 2010 / 2011 / 2012
Number of patients / 139 / 167 / 185 / 198 / 221 / 230 / 268 / 283 / 309 / 328
Age / 62.5±13.1 / 63.1±13.4 / 64.8±13.3 / 64.1±13.0 / 63.2±13.4 / 62.7±14.7 / 62.6±15.0 / 61.8±15.0 / 63.6±15.4 / 65.1±15.0
Gender female, % / 78 (56.1%) / 92 (55.1%) / 95 (51.3%) / 103 (52.0%) / 114 (51.6%) / 126 (54.8%) / 141 (52.6%) / 148 (52.3%) / 154 (49.8%) / 163 (49.7%)
Cause of ESRD, %
Glomerulonephritis / 87 (62.6%) / 92 (55.1%) / 89 (48.1%) / 93 (47.0%) / 97 (43.9%) / 99 (43.0%) / 106 (39.6%) / 109 (38.5%) / 113 (36.6%) / 130 (39.6%)
Diabetic nephropathy / 9 (6.5%) / 14 (8.4%) / 19 (10.3%) / 25 (12.6%) / 30 (13.6%) / 35 (15.2%) / 51 (19.0%) / 71 (25.1%) / 89 (28.8%) / 94 (28.7%)
Tubulointerstitial nephritis / 9 (6.5%) / 14 (8.4%) / 19 (10.3%) / 21 (10.6%) / 23 (10.4%) / 25 (10.9%) / 32 (11.9%) / 28 (9.9%) / 32 (10.4%) / 31 (9.5%)
Hypertension / 7 (5.0%) / 10 (6.0%) / 15 (8.2%) / 13 (6.6%) / 17 (7.7%) / 18 (7.8%) / 25 (9.3%) / 23 (8.1%) / 21 (6.8%) / 19 (5.8%)
Other / 11 (7.9%) / 16 (9.6%) / 17 (9.2%) / 19 (9.6%) / 23 (10.4%) / 22 (9.6%) / 20 (7.5%) / 20 (7.1%) / 24 (7.8%) / 23 (7.0%)
Unknown / 16 (11.5%) / 21 (12.6%) / 26 (14.1%) / 27 (13.6%) / 31 (14.0%) / 31 (13.5%) / 32 (11.9%) / 32 (11.3%) / 30 (9.7%) / 31 (9.5%)
Dialysis vintage, months / 43.5±48.1 / 44.6±49.4 / 50.4±51.1 / 55.2±50.3 / 58.4±54.1 / 62.1±55.9 / 57.9±58.1 / 56.2±64.6 / 60.3±54.2 / 71.3±62.7
Mortality, % / 12 (8.63%) / 14 (8.38%) / 13 (7.18%) / 25 (12.62%) / 22 (9.95%) / 21 (9.13%) / 31 (11.57%) / 22 (7.77%) / 41 (13.27%) / 26 (7.93%)
Kt/V / 1.49±0.27 / 1.46±0.23 / 1.46±0.28 / 1.47±0.24 / 1.51±0.26 / 1.41±0.20 / 1.50±0.31 / 1.52±0.28 / 1.47±0.28 / 1.50±0.31
Laboratory data
Hemoglobin, g/L / 113.8±15.2 / 114.4±15.6 / 114.2±15.6 / 113.9±16.2 / 113.4±15.0 / 113.8±17.4 / 114.5±16.2 / 114.4±14.2 / 114.3±15.1 / 114.3±15.3
Albumin, g/dl / 3.74±0.29 / 3.81±0.45 / 3.88±0.35 / 3.90±0.36 / 3.95±0.37 / 3.83±0.30 / 3.84±0.28 / 3.78±0.25 / 3.83±0.23 / 3.84±0.37
Calcium, mg/dl* / 9.34±0.92 / 9.05±0.97 / 9.06±0.77 / 9.01±0.98 / 9.19±0.97 / 9.29±0.93 / 9.27±0.84 / 9.32±1.09 / 9.35±0.84 / 9.57±0.91
Phosphorus, mg/dl / 5.77±1.59 / 6.08±1.91 / 5.67±1.56 / 5.70±1.33 / 5.74±1.94 / 5.84±1.33 / 5.73±1.41 / 5.74±1.38 / 5.81±1.31 / 5.59±1.18
Ca×P product, (mg/dl)2 / 53.7±14.8 / 54.4±16.0 / 51.2±14.1 / 51.3±13.0 / 52.5±17.5 / 54.1±12.9 / 53.4±14.6 / 53.8±15.5 / 54.4±13.8 / 53.5±11.9
Intact PTH, pg/ml / 127.6±324.6 / 202.8±275.5 / 288.8±293.2 / 203.9±218.0 / 350.5±317.7 / 379.0±393.7 / 345.6±341.6 / 348.1±316.2 / 426.0±293.3 / 334.9±393.3
Alkaline phosphatase, U/L / 70.9±32.9 / 74.2±36.0 / 69.0±53.7 / 96.0±67.2 / 74.6±51.9 / 100.1±81.5 / 102.3±82.3 / 93.6±64.3 / 87.3±53.6 / 83.5±49.4
Creatinine, mg/dl / 936.3±220.0 / 983.6±219.7 / 930.1±243.6 / 878.8±184.4 / 869.8±178.4 / 824.7±191.2 / 810.2±214.5 / 808.3±192.3 / 850.9±189.4 / 840.6±201.3
Total cholesterol, mg/dl / 145.3±27.5 / 151.5±36.0 / 143.6±46.0 / 165.4±36.5 / 187.3±41.7 / 177.2±42.6 / 182.8±42.2 / 180.0±41.3 / 176.7±40.0 / 174.3±40.5

All patients who received maintenance hemodialysis at Beijing Friendship Hospital (BFH) between 2003 and 2012 were included in cohort 1. Patients with complete medical records were enrolled and their clinical data were analyzed.

ESRD end-stage renal disease, PTH parathyroid hormone.

*Serum calcium concentrations were significantly different among the 10 time-points (F=7.245, P<0.001; analysis of variance).

Table 2. Characteristics of 120 MHD patients in cohort 2 and results of Cox regression analysis

Value / All-cause mortality / Cardio-cerebrovascular mortality / Transference calcification‡
HR / 95%CI / P / HR / 95%CI / P / HR / 95%CI / P
Age beginning dialysis / 51.0±13.8 (22-73) / 1.036 / 1.002-1.070 / 0.038* / 1.027 / 0.981-1.075 / 0.249 / 1.028 / 0.993-1.064 / 0.119
Gender female, % / 66 (55.0%) / 0.225 / 0.100- 0.509 / <0.001* / 0.043 / 0.008-0.241 / 0.001† / 1.291 / 0.503-3.314 / 0.696
Cause of ESRD, % / 1.180 / 0.885-1.575 / 0.26 / 1.406 / 0.942-2.097 / 0.095 / 1.286 / 0.980-1.687 / 0.069
Kt/V / 1.51±0.27 / 0.628 / 0.155-2.542 / 0.514 / 0.481 / 0.053-4.382 / 0.516 / 0.468 / 0.119-1.840 / 0.468
Laboratory data
Hemoglobin, g/L / 112.8±19.0 / 1.003 / 0.985-1.021 / 0.747 / 0.987 / 0.960-1.015 / 0.357 / 0.999 / 0.978-1.022 / 0.962
Albumin, g/dl / 4.10±0.34 / 0.041 / 0.007-0.250 / 0.001* / 0.332 / 0.022-4.937 / 0.423 / 1.187 / 0.167-8.465 / 0.864
Calcium, mg/dl / 9.24±0.86 / 0.178 / 0.023-1.389 / 0.100 / 0.275 / 0.096-0.788 / 0.016† / 1.131 / 0.188-6.805 / 0.893
Phosphorus, mg/dl / 5.77±1.58 / 0.162 / 0.008-3.475 / 0.244 / 0.389 / 0.116-1.308 / 0.127 / 1.039 / 0.066-16.291 / 0.978
Ca×P product, (mg/dl)2 / 53.0±14.8 / 1.213 / 0.874-1.683 / 0.249 / 1.137 / 0.991-1.304 / 0.068 / 1.011 / 0.756-1.353 / 0.941
Intact PTH, pg/ml / 131.8±221.4 / 1.000 / 0.997-1.002 / 0.697 / 1.000 / 0.997-1.002 / 0.703 / 0.999 / 0.996-1.001 / 0.333
Alkaline phosphatase, U/L / 71.9±36.0 / 1.005 / 0.996-1.014 / 0.302 / 1.009 / 0.995-1.023 / 0.208 / 0.998 / 0.989-1.008 / 0.714

Cohort 2 consisted of 120 patients treated at Beijing Friendship Hospital in 2003 with complete medical records. Cox regression analysis was used to calculate hazard ratios for all-cause mortality, cardio-cerebrovascular mortality, and transference calcification.

ESRD end-stage renal disease.

*Male sex and low serum albumin concentrations were independent risk factors for all-cause mortality.

†Male sex and calcium×phosphorus were independent risk factors for cardio-cerebrovascular mortality, while higher serum calcium concentrations were associated with reduced risk for cardio-cerebrovascular mortality.

‡There were no risk factors for transference calcification among the parameters above.

Table 3. Comparison of adverse events in cohort 3

Group DCa 1.75 (n=285) / Group DCa 1.5 (n=223)
2011 / 2012 / t/χ2 / P / 2011 / 2012 / t/χ2 / P / t/χ2 / P
Adverse events, %* / 0.373 / 0.830 / 0.230 / 0.891 / 3.848 / 0.146
Mortality / 0 / 0 / — / — / 0 / 0 / — / — / — / —
Cadiovascular disease / 2 (0.7%) / 3 (1.1%) / — / — / 5 (2.24%) / 8 (3.6%) / — / — / — / —
Cerebrovascular disease / 6 (2.1%) / 5 (1.8%) / — / — / 8 (8.6%) / 10 (4.5%) / — / — / — / —
Transference calcification / 16 (5.6%) / 19 (6.7%) / — / — / 13(5.8%) / 15 (6.7%) / — / — / — / —

Stable maintenance hemodialysis patients treated at Beijing Friendship Hospital, Beijing Chao-Yang Hospital, or Beijing Fu-Xing Hospital were enrolled into cohort 3 in January 2011. These patients were divided into two groups and received dialysate calcium (DCa) concentrations of 1.75 mmol/L or 1.5 mmol/L. In the DCa 1.75 group, the DCa was increased from 1.5 mmol/L to 1.75 mmol/L in January 2012. Patients were followedup for 2 years. The changes in parameters within each group were compared by paired t tests or χ2tests. There were no significant differences between the two groups at baseline.

*The new appearance of death, cardiovascular diseases, cerebrovascular diseases, and evidences of transference calcification according to imaging detections was not increased.

A B

C D

Figure 1. Proportions of patients in cohort 1 who achieved the KDOQI targets.

The proportions of patients meeting the KDOQI targets for serum calcium (8.4–9.5 mg/dL; A), serum phosphorus (3.5–5.5 mg/dL; B), calcium×phosphorus (<55 mg2/dl2; C), and serum intact parathyroid hormone (150–300 pg/mL; D) were calculated for every calendar year between 2003 and 2012.

Figure 2. Proportions of patients in cohort 1 who achieved the KDIGO targets.

The proportions of patients meeting the KDIGO targets for serum calcium (8.0–10.0 mg/dL; A), serum phosphorus (3.0–5.0 mg/dL; B), and serum intact parathyroid hormone (125–560 pg/mL; C) were calculated for every calendar year between 2003 and 2012.

A B

C D

Figure 4. Proportions of surviving patients (n=72) in cohort 1 who achieved the K targets.

Figure 4. Proportions of surviving patients (n=72) in cohort 1 who achieved the KDIGO targets.

The proportions of patients meeting the K地targets for serum calcium (8.0–10.0 mg/dL; A), serum phosphorus (3.0–5.0 mg/dL; B), and serum intact parathyroid hormone (125–560 pg/mL; C) were calculated for every calendar year between 2003 and 2012.

A B

C D

E F

Figure 5. Kaplan–Meier analysis of risk factors for transference calcification in cohort 2 (n=120).

As there were no risk factors for transference calcification according to the results of Cox regression analysis (Table 3), Kaplan–Meier analyses were done using parameters that were potentially associated with transference calcification. (A) Cumulative incidence of transference calcification in cohort 2. (B) Males vs. females (χ2=3.54; P=0.060). (C) Dialysis started at <50 vs. ≥50 years of age (χ2=2.62; P=0.106). (D) Serum albumin concentration <4.0 vs. ≥4.0 g/dL (χ2=1.37; P=0.242). (E) Serum calcium concentration <8.4, 8.4–9.5, and >9.5 mg/dL (χ2=1.67; P=0.434). (F) Calcium×phosphorus <55 and ≥55 mg2/dL2 (χ2=1.48; P=0.224).