The neutrophil percentage-to-albumin ratio is an independent risk factor for poor prognosis in peritoneal dialysis patients

Figures & data

Figure 1. Flowchart of study population.

Abbreviation: ALB: albumin; NPAR: neutrophil percentage-to-albumin ratio.

Table 1. Baseline characteristics across different NPAR groups.

Factors	Low (<1.765, n = 269)	Middle (≥1.756, <2.177, n = 269)	High (≥2.177, n = 269)	Total	p-value
Age (year)^a	56.2 ± 16.4	60.1 ± 15.6	63.5 ± 14.8	60.0 ± 16.0	<0.001
Survive (month)^a	45.2 (21, 69.5)	35.8 (15.5, 56)	33.8 (12, 55.5)	38.2 (15, 61.5)	<0.001
Male [case (%)]	156 (19.3)	153 (19.0)	150 (18.6)	459 (56.9)	0.872
Diabetes [case (%)]^a	52 (6.44)	80 (9.91)	102 (12.6)	234 (29.0)	<0.001
Hypertension [case (%)]	242 (30.0)	241 (29.9)	242 (30.0)	725 (89.9)	0.987
CVD [case (%)]	52 (19.3)	60 (7.43)	71 (8.80)	183 (22.7)	0.145
All cause Death [case (%)]^a	36 (4.46)	76 (9.42)	131 (16.2)	243 (30.1)	<0.001
Cardio-cerebrovascular Death [case (%)]^a	21 (2.60)	43 (5.33)	64 (7.93)	128 (15.86)	<0.001
WBC (×10^9g/L)^a	6.09 ± 1.69	6.37 ± 2.13	7.29 ± 2.80	6.59 ± 2.31	<0.001
Neutrophils (×10^9g/L)^a	3.71 ± 1.29	4.32 ± 1.72	5.49 ± 2.55	4.51 ± 2.06	<0.001
Neutrophil Percentage (%)^a	60.29 ± 8.83	66.90 ± 7.24	73.70 ± 8.60	66.96 ± 9.90	<0.001
Lymphocyte (×10^9g/L)^a	1.73 ± 0.57	1.38 ± 0.53	1.17 ± 0.46	1.43 ± 0.57	<0.001
NLR^a	2.24 (1.67, 2.80)	3.18 (2.45, 3.90)	4.8 (3.20, 6.40)	3.23 (2.18, 4.28)	<0.001
Monocyte (×10^9g/L)^a	0.37 ± 0.18	0.40 ± 0.18	0.45 ± 0.27	0.41 ± 0.22	<0.001
Hemoglobin (g/L)^a	116.9 ± 21.9	113.0 ± 23.3	104.5 ± 23.1	111.5 ± 23.4	<0.001
Platelet (g/L)	179.7 ± 56.2	175.0 ± 69.8	184.3 ± 79.2	179.7 ± 69.0	0.296
PLR	170.5 (130, 211)	169.5 (130, 209)	177 (130, 209)	173 (129, 217)	0.649
SCR (mmol/L)^a	756 ± 287	776 ± 325	680 ± 306	737 ± 309	0.01
BUN (mmol/L)^a	18.47 ± 5.40	18.66 ± 6.03	17.42 ± 6.69	18.18 ± 6.08	0.039
Uric acid (mmol/L)^a	439 ± 99	446 ± 110	412 ± 102	443 ± 105	<0.001
Ca^2+ (mmol/L)^a	2.24 ± 0.20	2.17 ± 0.22	2.06 ± 0.23	2.16 ± 0.23	<0.001
Phosphorus (mmol/L)^a	1.54 ± 0.46	1.57 ± 0.48	1.43 ± 0.48	1.51 ± 0.48	0.001
Albumin (g/L)^a	39.1 ± 4.7	34.5 ± 4.3	27.4 ± 4.9	33.7 ± 6.6	<0.001
Prealbumin (g/L)^a	0.34 ± 0.09	0.30 ± 0.09	0.24 ± 0.10	0.29 ± 0.10	<0.001
CRP (mg/L)^a	6.94 ± 5.45	8.46 ± 12.47	27.46 ± 44.91	14.28 ± 28.63	<0.001
CAR (×10^-3)^a	0.16 (0.13, 0.18)	0.18 (0.15, 0.20)	0.69 (0.19, 1.19)	0.19 (0.15, 0.23)	<0.001
iPTH (pg/ml)^a	263 ± 201	266 ± 255	217 ± 238	248 ± 233	0.023
Total bilirubin (μmol/L)^a	7.35 ± 2.74	7.04 ± 3.82	6.57 ± 3.11	6.99 ± 3.27	0.021
Cholesterol (mmol/L)^a	4.90 ± 1.29	4.74 ± 1.27	4.61 ± 1.16	4.75 ± 1.25	0.031
Triglyceride (mmol/L)^a	1.86 ± 1.09	1.90 ± 1.56	1.56 ± 0.96	1.78 ± 1.24	0.002
LDL (mmol/L)	2.86 ± 0.93	2.77 ± 1.10	2.75 ± 1.00	2.80 ± 1.01	0.366
HDL (mmol/L)	1.19 ± 0.46	1.14 ± 0.49	1.17 ± 0.53	1.17 ± 0.49	0.51
Blood glucose (mmol/L)	5.39 ± 1.46	5.34 ± 1.69	5.56 ± 2.35	4.53 ± 1.87	0.343
K^+(mmol/L)^a	4.12 ± 0.70	3.99 ± 0.79	3.86 ± 0.81	3.99 ± 0.78	0.001

Data are expressed as mean (SD) for Normally distributed continuous variables, median (interquartile range) for Non normally distributed variables, or count (percentage) for categorical variables.

Abbreviation: WBC: white blood cell; NLR: neutrophil to lymphocyte ratio; PLR: platelet to lymphocyte ratio; SCR: serum creatinine; BUN: blood urea nitrogen; CRP: C-reactive protein; CAR:C-reactive protein to albumin; iPTH: intact parathyroid hormone; LDL: low density lipoprotein; HDL: high density lipoprotein.

Figure 2. Kaplan Meier curves for overall survival of patients grouped according to NPAR.

Abbreviation: NPAR: neutrophil percentage-to-albumin ratio.

Figure 3. Cumulative incidence of cardio-cerebrovascular death among the groups (Fine-Gray competing risk model, p < 0.05).

Table 2. Univariate and multivariate analysis of risk factors for all-cause mortality in PD patients.

	Neu (%)		Albumin		NPAR ≥ 1.756, <2.177		NPAR ≥ 2.177
	HR (95%CI)	p-value	HR (95%CI)	p-value	HR (95%CI)	p-value	HR (95%CI)	p-value
Model 1	1.02 (1.00–1.03)	0.008	0.89 (0.87–0.91)	<0.001	2.52 (1.69–3.75)	<0.001	4.46 (3.08–6.45)	<0.001
Model 2	1.02 (1.00–1.03)	0.003	0.90 (0.88–0.92)	<0.001	2.12 (1.42–3.16)	<0.001	3.60 (2.48–5.23)	<0.001
Model 3	1.02 (1.01–1.03)	0.002	0.90 (0.88–0.92)	<0.001	2.16 (1.45–3.23)	<0.001	3.37 (2.30–4.93)	<0.001
Model 4	1.01 (1.00–1.03)	0.050	0.90 (0.88–0.92)	<0.001	2.16 (1.44–3.22)	<0.001	3.13 (2.12–4.62)	<0.001

Model 1: unadjusted.

Model 2: adjust for Age, sex, hypertension, diabetes and cardiovascular disease.

Model 3: adjust for model 2 + hemoglobin, platelet, serum creatinine, phosphorus.

Model 4: adjust for model 3 + low density lipoprotein, C-reactive protein.

Abbreviation: NPAR: neutrophil percentage-to-albumin ratio; Neu (%): neutrophil percentage.

The selected covariates were assessed for multicollinearity using variance inflation factor (VIF) analysis, and no significant multicollinearity was observed among the covariates (VIF < 1.5).

Table 3. Association of neu (%), albumin and NPAR with cardio-cerebrovascular death (Fine-Gray competing risk model).

	Neu (%)		Albumin		NPAR ≥ 1.756, <2.177		NPAR ≥ 2.177
	SHR (95%CI)	p-value	SHR (95%CI)	p-value	SHR (95%CI)	p-value	SHR (95%CI)	p-value
Model 1	1.00 (0.97–1.02)	0.95	0.92 (0.89–0.94)	<0.001	2.25 (1.35–3.77)	0.002	3.12 (1.90–5.11)	<0.001
Model 2	1.00 (0.98–1.02)	<0.001	0.92 (0.90–0.95)	<0.001	1.92 (1.14–3.24)	0.01	2.44 (1.48–4.03)	<0.001
Model 3	1.00 (0.98–1.02)	0.95	0.93 (0.90–0.96)	<0.001	1.92 (1.14–3.23)	0.01	2.27 (1.35–3.81)	0.002
Model 4	1.00 (0.98-1.02)	0.91	0.93 (0.90-0.96)	<0.001	1.94 (1.15-3.27)	0.01	2.30 (1.34-3.91)	0.002

Model 1: unadjusted.

Model 2: adjust for Age, sex, hypertension, diabetes and cardiovascular disease.

Model 3: adjust for model 2 + hemoglobin, platelet, serum creatinine, phosphorus.

Model 4: adjust for model 3 + low density lipoprotein, C-reactive protein.

Abbreviation: NPAR: neutrophil percentage-to-albumin ratio; Neu (%): Neutrophil Percentage.

Figure 4. ROC curve of various parameters and overall performance in predicting death in peritoneal dialysis patients.

Abbreviation: NPAR: neutrophil percentage-to-albumin ratio; CRP:C-reactive protein, NLR: neutrophil to lymphocyte ratio, CAR: C-reactive protein to albumin ratio, PLR: platelet to lymphocyte ratio

Table 4. Single factor ROC analysis of NPAR, CRP, albumin, NLR, CAR, PLR and Overall performance.

	AUC	95%CI	p-value	Cutoff	DeLong p-value	Sensitivity	Specificity	D-stat	R^2
NPAR	0.714	0.675–0.754	<0.001	2.06		0.65	0.71	0.428	0.150
CRP	0.597	0.551–0.644	<0.001	7.35	<0.001	0.39	0.83	0.195	0.032
Albumin	0.754	0.719–0.789	<0.001	32.15	0.005	0.72	0.68	0.508	0.212
NLR	0.589	0.543–0.635	<0.001	3.58	<0.001	0.50	0.70	0.178	0.018
CAR	0.698	0.658–0.738	<0.001	0.192	0.462	0.65	0.70	0.396	0.048
PLR	0.533	0.488–0.578	0.147	211.05	<0.001	0.34	0.76	0.066	0.005
Overall	0.755	0.719–0.790	<0.001	–	<0.001	0.72	0.68	0.509	0.175

Abbreviation: NPAR: NPAR: neutrophil percentage-to-albumin ratio; CRP: C-reactive protein; NLR: neutrophil to lymphocyte ratio; CAR:C-reactive protein to albumin; PLR: platelet to lymphocyte ratio.

Figure 5. ROC curve based on multifactor analysis.

Abbreviation: covariates: age, sex, hypertension, diabetes, cardiovascular disease, hemoglobin, platelet, serum creatinine, phosphorus, low density lipoprotein and C-reactive protein; NPAR: neutrophil percentage-to-albumin ratio.

ALB: albumin.

Table 5. Multifactor ROC analysis.

	AUC	95%CI	p-value	D-stat	R^2
Covariates	0.771	0.737–0.805	<0.001	0.542	0.261
Covariates + NPAR	0.802	0.770–0.834	<0.001	0.604	0.314
Covariates + albumin	0.809	0.779–0.840	<0.001	0.618	0.343
Covariates + albumin + NPAR	0.811	0.780–0.841	<0.001	0.622	0.343

Abbreviation: Covariates: age, sex, hypertension, diabetes, cardiovascular disease, hemoglobin, platelet, serum creatinine, phosphorus, low density lipoprotein and C-reactive protein; NPAR: neutrophil percentage-to-albumin ratio.

Figure 6. Calibration plot of model 4, NPAR, CRP, ALB, NLR, CAR, PLR and Overall performance.

Abbreviation: NPAR: neutrophil percentage-to-albumin ratio; CRP: C-reactive protein; ALB: albumin; NLR: neutrophil to lymphocyte ratio; CAR:C-reactive protein to albumin; PLR: platelet to lymphocyte ratio.