The optimal range of serum intact parathyroid hormone for a lower risk of mortality in the incident hemodialysis patients

Figures & data

Table 1. Baseline characteristics of study participants.

Characteristics	Total (n = 346)	iPTH < 150 pg/mL (n = 110)	150≤iPTH≤300 pg/mL (n = 94)	iPTH > 300 pg/mL (n = 142)	p-Value
Age, (years)	62.08 ± 14.56	66.02 ± 9.99	61.68 ± 13.93	59.25 ± 14.71	<0.001
Male sex, n (%)	182 (52.60)	56 (50.91)	58 (61.70)	68 (47.89)	0.105
Smoking, n (%)	106 (30.64)	29 (26.36)	32 (34.04)	45 (31.69)	0.465
BMI (kg/m^2)	22.67 ± 3.42	22.28 ± 3.63	22.09 ± 3.44	23.34 ± 3.13	0.008
Diabetes mellitus, n (%)	194 (56.07)	86 (78.18)	46 (48.94)	62 (43.66)	<0.001
Hypertension, n (%)	294 (84.97)	92 (83.64)	74 (78.72)	128 (90.14)	0.050
Medication use
Phosphate binders, n (%)	204 (58.96)	52 (47.27)	48 (51.06)	104 (73.24)	<0.001
Vitamin D, n (%)	146 (42.20)	50 (45.46)	36 (38.30)	60 (42.25)	0.587
Cinacalcet, n (%)	37 (10.69)	11 (10.00)	10 (10.64)	16 (11.27)	0.949
Vascular access type
Arteriovenous fistula, n (%)	170 (49.13)	50 (45.46)	51 (54.26)	69 (48.59)	0.450
Catheter, n (%)	174 (50.30)	59 (53.64)	42 (44.68)	73 (51.41)	0.418
Other, n (%)	2 (0.58)	1 (0.91)	1 (1.06)	0	0.491
Laboratory parameters
Hemoglobin (g/L)	110.92 ± 16.20	107.35 ± 15.91	111.43 ± 15.61	113.37 ± 16.42	0.013
Albumin (g/L)	37.82 ± 4.50	34.99 ± 4.14	38.09 ± 4.94	39.83 ± 3.14	<0.001
Triglycerides (mmol/L)	2.08 ± 1.14	1.97 ± 0.89	1.87 ± 1.05	2.30 ± 1.31	0.009
Total cholesterol (mmol/L)	4.33 ± 1.04	4.55 ± 1.00	4.20 ± 1.25	4.25 ± 0.90	0.028
hs-CRP (mg/L)	7.93±5.53	10.18 ± 7.46	7.02 ± 4.45	6.79 ± 3.59	<0.001
Calcium (mmol/L)	2.23 ± 0.20	2.25 ± 0.17	2.22 ± 0.20	2.23 ± 0.21	0.405
Phosphorus (mmol/L )	1.98 ± 0.63	1.54 ± 0.35	1.84 ± 0.61	2.40 ± 0.55	<0.001
iPTH (pg/ mL)	259 (118.448)	81 (51.116)	220 (173.280)	541 (393.646)	<0.001
25 (OH)VitD (mg/mL)	9.25 ± 3.71	9.66 ± 3.45	8.60 ± 3.39	9.37 ± 4.07	0.114
eGFR (ml/min/1.73 m^2)	6.724 ± 0.587	6.646 ± 0.611	6.756 ± 0.509	6.724 ± 0.587	0.321
sp Kt/V	1.39 ± 0.25	1.34 ± 0.21	1.40 ± 0.24	1.42 ± 0.27	0.036

Data were presented as mean ± SD or median (interquartile range) for continuous variables, and number (%) for categorical variables. BMI: body mass index; hs-CRP: high sensitive C-reactive protein; iPTH: intact parathyroid hormone; 25 (OH)VitD: 25-hydroxy vitamin D.

Table 2. Multivariable Cox regression analyses for the risk factors of mortality.

Characteristics	All-cause mortality		CVD mortality
	HR (95%CI)	p-Value	HR (95%CI)	p-Value
Age, (years)	1.025 (1.010–1.039)	0.001	1.032 (1.015–1.050)	<0.001
History of
Diabetes	1.658 (1.115–2.466)	0.013	2.934 (1.688–5.100)	<0.001
Hypertension	–	–	2.540 (1.315–4.908)	0.006
Vitamin D used	0.573 (0.370–0.888)	0.013	–	–
sp Kt/V	0.089 (0.038–0.208)	<0.001	0.048 (0.018–0.129)	<0.001
Hemoglobin (g/L)	0.980 (0.969–0.991)	<0.001	0.975 (0.961–0.988)	<0.001
Albumin (g/L)	0.923 (0.883–0.965)	<0.001	–	–
Calcium
<2.10 mmol/L	1.699 (1.162–2.485)	0.006	–	–
2.10–2.37 mmol/L	1.000 (reference)		–	–
>2.37 mmol/L	0.920 (0.602–1.405)	0.698	–	–
Phosphorus
<1.13 mmol/L	0.702 (0.454–1.087)	0.112	0.957 (0.580–1.484)	0.092
1.13–1.78 mmol/L	1.000 (reference)		1.000 (reference)
>1.78 mmol/L	1.674 (1.117–2.507)	0.013	1.560 (1.098–2.484)	0.014
iPTH
<150 pg/mL	4.022 (2.493–6.489)	<0.001	4.729 (2.535–8.822)	<0.001
150–300 pg/mL	1.000 (reference)		1.000 (reference)
>300 pg/mL	1.752 (1.008–3.044)	0.047	1.867 (1.007–3.565)	0.049

Model was adjusted for age, gender, BMI, comorbidities of diabetes and hypertension, medications (phosphate binders, vitamin D, and Cinacalcet), vascular access type, the serum level of hemoglobin, albumin, triglycerides, total cholesterol, hs-CRP, calcium, phosphate, iPTH, 25 (OH)VitD, eGFR, and sp K_t/V. CVD: cardiovascular disease; HR: hazard ratio; CI: confidence interval; iPTH: intact parathyroid hormone.

Figure 1. Multivariate adjusted hazard ratio (95% CI) for all-cause mortality according to the levels of serum iPTH. iPTH: intact parathyroid hormone; HR: hazard ratio; CI: confidence interval.

Figure 2. Multivariate adjusted hazard ratio (95% CI) for CVD mortality according to the levels of serum iPTH. iPTH: intact parathyroid hormone; HR: hazard ratio; CI: confidence interval.

Table 3. Multivariable Cox regression analyses for mortality according to the different range of serum iPTH.

iPTH (pg/mL)	All-cause mortality			CVD mortality
	No. (%) of event	HR (95%CI)	p-Value	No. (%) of event	HR (95%CI)	p-Value
<150	82 (74.55)	4.022 (2.493–6.489)	<0.001	56 (50.91)	4.729 (2.535–8.822)	<0.001
150–299	28 (29.79)	reference 1.000		15 (15.96)	reference 1.000
300–449	20 (33.33)	1.614 (0.861–3.027)	0.135	11 (18.33)	1.373 (0.603–3.127)	0.450
450–599	7 (23.33)	3.475 (1.270–9.505)	0.015	7 (23.33)	7.16 (2.475–12.735)	<0.001
600–749	8 (30.77)	3.605 (1.416–9.177)	0.007	8 (30.77)	6.817 (2.594–13.912)	<0.001
≥750	12 (46.15)	5.016 (2.278–11.043)	<0.001	12 (46.15)	11.745 (4.726–17.187)	<0.001

Model was adjusted for age, gender, BMI, comorbidities of diabetes and hypertension, medications (phosphate binders, vitamin D, and Cinacalcet), vascular access type, the serum level of hemoglobin, albumin, triglycerides, total cholesterol, hs-CRP, calcium, phosphate, iPTH, 25 (OH)VitD, eGFR, and sp K_t/V. CVD: cardiovascular disease; HR: hazard ratio; CI: confidence interval; iPTH: intact parathyroid hormone.