Prognosis and factors related to severe secondary hyperparathyroidism in long-term peritoneal dialysis patients

Figures & data

Figure 1. Flowchart of patient enrollment and follow-up.

Table 1. Baseline clinical characteristics and serum parameters of patients with sSHPT on PD.

Parameters	Total (n = 771)	sSHPT (n = 75)	Non-sSHPT (n = 696)	p Value
Age (years) (mean ± SD)	51.24 ± 14.306	55.07 ± 13.744	50.83 ± 14.311	.015^a
Male, n (%)	421 (54.60)	46 (62.16)	375 (53.80)	.105^c
PD vintage (months) (median, pc 25–75)	28.34 (9.20, 39.9)	35.30 (12.10, 54.10)	27.59 (9.10, 38.67)	.02^b
Primary disease, n (%)
Primary glomerular disease	371 (48.12)	49 (65.33)	322 (46.26)	<.001^c
Diabetic nephropathy	162 (21.01)	3 (4.00)	159 (22.84)	<.001^c
Hypertension	158 (20.49)	18 (24.00)	140 (20.11)	.485^c
Others	80 (10.38)	5 (6.67)	75 (10.78)	1.00^c
Complicated with diabetes, n (%)	181 (23.48)	7 (9.33)	174 (25.00)	.001^c
Cardiovascular disease, n (%)	397 (51.10)	42 (56.00)	352 (50.57)	.535
eGFR (mL/min/1.73 m^2) (mean ± SD)	5.12 ± 10.01	5.13 ± 7.19	5.82 ± 5.30	.302^a
Dialysis dose (L) (median, pc 25–75)	6.98 (6, 8)	7.54 (6, 8)	6.92 (6, 8)	.002^b
Average daily dialysate glucose concentration (g/dL) (mean ± SD)	1.70 ± 0.36	1.75 ± 0.33	1.69 ± 0.36	.196^a
Kt/V (mean ± SD)	1.91 ± 0.52	1.74 ± 0.44	1.93 ± 0.53	.006^a
Creatinine D/P4 (mean ± SD)	0.63 ± 0.12	0.62 ± 0.11	0.64 ± 0.13	.258^a
Frequency of visit (times/year) (median, pc 25–75)	2.25 (2, 3)	2.37 (2, 3)	2.22 (2, 3)	.17^b
Ultrafiltration volume (mL/d) (median, pc 25–75)	490.91 (200, 800)	396.87 (0, 750)	199.16 (0, 400)	.003^b
Urine volume (mL/d) (median, pc 25–75)	726 (260, 1000)	366.40 (0, 650)	639.45 (175, 1000)	.120^b
Peritoneum transport type
H + HA, n (%)	179 (43.55)	28 (43.75)	151 (43.52)	.972^c
L + LA, n (%)	232 (56.45)	36 (56.25)	196 (56.48)
Use ACEI, n (%)	50 (6.48)	6 (8.95)	44 (7.07)	.573^c
Use ARB, n (%)	420 (54.47)	45 (62.50)	375 (55.72)	.270^c
Use calcium-phosphate binder, n (%)	184 (31.56)	17 (29.83)	167 (31.75)	.607^c
Use calcium-free phosphate binder, n (%)	21 (3.60)	0 (0)	21 (3.99)
Use calcitriol (n, %)
Maintenance dose	65 (9.21)	9 (13.04)	56 (8.79)	<.001^c
Pulse dose	24 (3.40)	8 (11.59)	16 (2.51)
Not used	617 (87.39)	52 (75.36)	565 (88.70)
Hb (g/L) (mean ± SD)	107.71 ± 21.08	101.60 ± 19.56	107.77 ± 21.12	.016^a
ALB (g/L) (mean ± SD)	33.77 ± 5.912	34.672 ± 5.25	33.675 ± 5.97	.168^a
Serum phosphate (mg/dL) (median, pc 25–75)	32.148 (21.42, 32.04)	34.30 (26.22, 39.67)	31.67 (20.99, 31.26)	<.001^b
Serum calcium (mg/dL) (mean ± SD)	40.57 ± 22.53	49.87 ± 70.97	39.56 ± 3.70	<.001^a
Calcium-phosphorus product (mg/dL) (median, pc 25–75)	51.90 (33.81, 51.78)	67.17 (42.27, 70.20)	49.66 (33.22, 50.04)	<.001^b
iPTH (pg/mL) (mean ± SD)	294.24 ± 285.38	534.35 ± 476.29	224.12 ± 192.11	<.001^a
SCr (mg/dL) (mean ± SD)	104.66 ± 46.23	117.66 ± 31.53	103.27 ± 47.34	.014^a
UA (mg/dL) (mean ± SD)	6.37 ± 1.37	6.74 ± 1.37	6.33 ± 1.36	.022^a
CRP (mg/dL) (median, pc 25–75)	2.107 (0.615, 5.987)	2.625 (0.735, 7.363)	1.945 (0.56, 5.69)	.311^b

sSHPT: severe secondary hyperparathyroidism; H: high peritoneal transport status; HA: high average peritoneal transport status; L: low peritoneal transport status; LA: low average peritoneal transport status; ACEI: angiotensin-converting enzyme inhibitors; ARB: angiotensin receptor blockers; iPTH: intact parathyroid hormone; Hb: hemoglobin; ALB: albumin; SCr: serum creatinine; UA: uric acid.

Comparison was determined by t-test, Wilcoxon’s rank sum test or Chi‐square test.

^a t-test.

^b Wilcoxon’s rank sum test.

^c Chi² test.

Table 2. Risk factors for progression to sSHPT in patients on PD in multivariable logistic regression analysis.

Parameters	Univariable			Multivariable
	OR	95% confidence interval	p Value	OR	95% confidence interval	p Value
Sex [ref. male]	1.358	0.833–2.212	.219
PD vintage (months) [continuous]	1.022	1.004–1.040	.015*	1.036	1.013–1.060	.002*
Age (years) [continuous]	0.991	0.983–0.999	.023*	0.994	0.980–1.009	.454
eGFR (mL/min/1.73 m^2) [continuous]	0.957	0.883–1.039	.295
Diabetes [ref. no.]	3.438	1.546–7.642	.002*	3.776	1.375–10.374	.010*
Cardiovascular disease [ref. no.]	1.177	0.719–1.928	.517
Kt/V (↑(72) [continuous]	0.924	0.873–0.978	.006*	0.919	0.859–0.984	.015*
Creatinine D/P4 [continuous]	0.256	0.025–2.642	.253
Frequency of visits (re time/year) [continuous]	1.226	0.918–1.637	.167
24-hour urine volume (mL) [continuous]	1.000	0.999–1.000	.139
Baseline iPTH (↑(se pg/mL) [continuous]	1.194	1.114–1.278	.000*	1.410	1.206–1.649	<.001*
Baseline serum phosphate (ru mg/dL) [continuous]	0.995	0.957–1.034	.791
Calcium-phosphorus product (lc mg/dL) [continuous]	1.199	0.835–1.721	.327
Baseline Hb (ase g/L) [continuous]	1.012	0.903–1.135	.834
Baseline serum ALB (rum g/L) [continuous]	1.298	0.852–1.980	.225
Serum phosphate (er mg/dL) [continuous]	1.003	0.972–1.035	.866
Serum calcium (er mg/dL) [continuous]	0.986	0.879–1.106	.806
SCr (Cr mg/dL) [continuous]	1.001	1.000–1.001	.034*	1.000	1.000–1.001	.189
UA (A9 mg/dL) [continuous]	1.003	1.000–1.006	.022*	1.002	0.998–1.006	.338
Hb (b 0 g/L) [continuous]	0.872	0.779–0.975	.016*	0.878	0.746–1.033	.117
ALB (↑( g/L) [continuous]	1.030	0.988–1.073	.168
Use ACEI [ref. no.]	0.774	0.317–1.890	.574
Use ARB [ref. no.]	0.737	0.447–1.213	.230
Use phosphorus binding agent [ref. no.]	0.990	0.578–1.697	.972
Use calcitriol [ref. no.]	1.509	0.720–3.161	.275
Baseline iPTH × PD vintage (months) [continuous]	1.000	1.000–1.000	.488	1.000	1.000–1.000	.092

sSHPT: severe secondary hyperparathyroidism; iPTH: intact parathyroid hormone; Hb: hemoglobin; ALB: albumin; Cr: creatinine; UA: uric acid.

* p Value <.05.

Figure 2. Kaplan–Meier’s survival curves of the sSHPT group and non-rSHPT group for OW cumulative mortality.

Figure 3. Kaplan–Meier’s survival curves of the sSHPT group and non-rSHPT group for PSM cumulative mortality.

Table 3. Association between the sSHPT and all-cause mortality in patients on PD in multivariable Cox regression analysis.

Variable	Before matching				Overlap weighting		Propensity score matching
	Cox		Time-dependent Cox		Time-dependent Cox		Time-dependent Cox
	HR (95% CI)	p Value	HR (95% CI)	p Value	HR (95% CI)	p Value	HR (95% CI)	p Value
Univariable analysis
Non-sSHPT	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
sSHPT	1.02 [0.71, 1.47]	.896	1.56 [1.08, 2.26]	.018	2.13 [1.40, 3.22]	<.001	2.37 [1.38, 4.08]	.002
Multivariable analysis^a
Non-sSHPT	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
sSHPT	0.99 [0.68, 1.44]	.946	1.57 [1.08, 2.30]	.02	2.50 [1.66, 3.76]	<.001	2.75 [1.56, 4.86]	<.001

HR: hazard ratio; CI: confidence interval.

^a Adjusted for age, gender, diabetes, hemoglobin, albumin, phosphorus and high-sensitive C-reactive protein on the basis.

Figure 4. Kaplan–Meier’s survival curves of the sSHPT group and non-rSHPT group for OW infection mortality.

Figure 5. Kaplan–Meier’s survival curves of the sSHPT group and non-sSHPT group for PSM infection mortality.

Table 4. Association between the sSHPT and mortality due to infection in patients on PD in multivariable Cox regression analysis.

Variable	Before matching				Overlap weighting		Propensity score matching
	Cox		Time-dependent Cox		Time-dependent Cox		Time-dependent Cox
	HR (95% CI)	p Value	HR (95% CI)	p Value	HR (95% CI)	p Value	HR (95% CI)	p Value
Univariable analysis
Non-sSHPT	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
sSHPT	1.43 [0.68, 3.03]	.347	2.07 [0.97, 4.41]	.061	3.54 [1.50, 8.36]	.004	7.13 [1.51, 33.63]	.013
Multivariable analysis^a
Non-sSHPT	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
sSHPT	1.49 [0.68, 3.25]	.322	2.19 [0.99, 4.85]	.054	4.78 [2.06, 11.12]	<.001	7.47 [1.42, 39.29]	.018

HR: hazard ratio, CI: confidence interval.

^a Adjusted for age, gender, diabetes, hemoglobin, albumin, phosphorus and high-sensitive C-reactive protein on the basis.

Figure 6. Kaplan–Meier’s survival curves of the sSHPT group and non-sSHPT group for OW peritonitis incidence.

Figure 7. Kaplan–Meier’s survival curves of the sSHPT group and non-sSHPT group for PSM peritonitis incidence.

Table 5. Association between the rSHPT and peritonitis incidence in patients on PD in multivariable Cox regression analysis.

Variable	Before matching				Overlap weighting		Propensity score matching
	Cox		Time-dependent Cox		Time-dependent Cox		Time-dependent Cox
	HR (95% CI)	p Value	HR (95% CI)	p Value	HR (95% CI)	p Value	HR (95% CI)	p Value
Univariable analysis
Non-sSHPT	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
sSHPT	1.29 [0.92, 1.81]	.137	1.68 [1.16, 2.43]	.006	1.22 [0.85, 1.76]	.28	1.33 [0.85, 2.07]	.208
Multivariable analysis^a
Non-sSHPT	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
sSHPT	1.32 [0.93, 1.87]	.126	1.57 [1.07, 2.30]	.022	1.23 [0.86, 1.75]	.255	1.24 [0.78, 1.96]	.368

HR: hazard ratio; CI: confidence interval.

^a Adjusted for age, gender, diabetes, hemoglobin, albumin, phosphorus and high-sensitive C-reactive protein on the basis.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.