J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://jocmr.elmerjournals.com

Original Article

Volume 18, Number 1, January 2026, pages 31-41

Efficacy and Safety of Regional Citrate Anticoagulation in Neurocritical Care Patients With Chronic Severe Hypernatremia Undergoing Continuous Renal Replacement Therapy: A Single-Center Retrospective Study

Figure 1. Flow chart of enrollment. Included patients (n = 98) were divided into two groups: regional citrate anticoagulation (RCA) groups (n = 70) and no anticoagulation (NA) groups (n = 28). A 1:1 propensity score matching (PSM) was performed to create two balanced groups: “NA group” and “RCA group,” each with n = 21 patients.

Figure 2. Kaplan-Meier curve shows the filter lifespan of the first filter of the regional citrate anticoagulation (RCA) group and no anticoagulation (NA) group in the original cohort (a) and the matched cohort (b). The Kaplan-Meier survival curves demonstrated significant differences in first filter lifespan between the two anticoagulation groups. The overall median filter survival time was 39.0 h (95% CI, 34.1–43.9). Median filter lifespan was 22.5 h in NA group (95% CI 19.9–25.1). Median lifespan was significantly longer at 43.5 h in RCA group (95% CI, 39.8–47.2) (a). Kaplan-Meier survival curves after matching. The first filter lifespan was considerably longer in the RCA group compared to the NA group (P < 0.001) (b). 95% CI: 95% confidence interval.

Figure 3. Multivariable Cox proportional risk model regression analysis affecting the lifespan of the first filter. Regional citrate anticoagulation (RCA) remained a significant independent predictor of prolonged first filter lifespan after adjustment for covariates (HR = 0.09, 95% CI, 0.05−0.18). 95% CI: 95% confidence interval; HR: hazard ratio.

**Table 1.** Baseline Characteristics of Patients Before and After PSM
Variables	Before PSM	After PSM
ALB: albumin; AKI: acute kidney injury; APACHE II: Acute Physiology and Chronic Health Evaluation II; aPTT: activated partial thromboplastin time; GCS: Glasgow Coma Scale; Hb: hemoglobin; NA: no anticoagulation; PLT: platelet; PSM: propensity score matching; PT: prothrombin time; RCA: regional citrate anticoagulation.
Male	69 (70.4)	49 (70)	20 (71.4)	0.889	33 (78.6)	16 (76.2)	17 (81)	> 0.99
Age, years	53.0 ± 14.5	52.5 ± 13.0	54.2 ± 17.9	0.603	53.5 ± 16.7	51.5 ± 14.6	55.4 ± 18.8	0.461
APACHE II score	28.3 ± 4.5	27.9 ± 4.5	29.2 ± 4.5	0.213	28.4 ± 3.2	28.8 ± 3.0	28.0 ± 3.4	0.448
GCS score	3.0 ± 1.8	3.2 ± 2.0	2.6 ± 1.2	0.146	2.8 ± 1.1	2.7 ± 1.0	2.8 ± 1.3	0.791
Mechanical ventilation	86 (87.8)	62 (88.6)	24 (85.7)	0.738	40 (95.2)	20 (95.2)	20 (95.2)	> 0.99
Neurologic disease				0.429				0.156
Traumatic brain injury	35 (35.7)	27 (38.6)	8 (28.6)		15 (35.7)	7 (33.3)	8 (38.1)
Intracerebral hemorrhage	39 (39.8)	25 (35.7)	14 (50)		21 (50.0)	13 (61.9)	8 (38.1)
Subarachnoid hemorrhage	4 (4.1)	4 (5.7)	0 (0)		0 (0)	0 (0)	0 (0)
Other categories	20 (20.4)	14 (20)	6 (21.4)		6 (14.3)	1 (4.8)	5 (23.8)
Post craniocerebral operation	74 (75.5)	55 (78.6)	19 (67.9)	0.265	30 (71.4)	15 (71.4)	15 (71.4)	> 0.99
Comorbidity
Hypertension	50 (51.0)	34 (48.6)	16 (57.1)	0.443	24 (57.1)	11 (52.4)	13 (61.9)	0.533
Diabetes	23 (23.5)	14 (20)	9 (32.1)	0.2	11 (26.2)	4 (19)	7 (33.3)	0.292
Use of osmotic diuretics	83 (84.7)	61 (87.1)	22 (78.6)	0.353	36 (85.7)	18 (85.7)	18 (85.7)	> 0.99
AKI	70 (71.4)	46 (65.7)	24 (85.7)	0.048	33 (78.6)	16 (76.2)	17 (81)	> 0.99
AKI stage				0.003				0.616
AKI stage 1	39 (39.8)	30 (42.9)	9 (32.1)		16 (38.1)	8 (38.1)	8 (38.1)
AKI stage 2	20 (20.4)	13 (18.6)	7 (25.0)		10 (23.8)	6 (28.6)	4 (19.0)
AKI stage 3	11 (11.2)	3 (4.3)	8 (28.6)		7 (16.7)	2 (9.5)	5 (23.8)
Urine volume, mL	3,415.1 ± 1,776.0	3,514.0 ± 1,715.4	3,167.8 ± 1,929.5	0.386	3,502.2 ± 1,684.6	3,597.8 ± 1,593.8	3,406.6 ± 1,805.1	0.718
Serum sodium, mmol/L	171.7 ± 8.9	172.3 ± 9.4	170.4 ± 7.7	0.349	171.2 ± 8.4	170.2 ± 9.3	172.1 ± 7.6	0.472
Total calcium, mmol/L,	2.3 ± 0.2	2.3 ± 0.2	2.3 ± 0.2	0.304	2.3 ± 0.2	2.4 ± 0.3	2.3 ± 0.2	0.523
Serum creatinine, µmol/L,	176.3 ± 127.2	147.8 ± 95.7	247.8 ± 165.2	< 0.001	205.3 ± 132.4	195.2 ± 113.1	215.3 ± 151.5	0.629
Serum urea, mmol/L	17.4 ± 11.3	16.5 ± 11.3	19.8 ± 11.1	0.191	20.3 ± 11.2	20.5 ± 9.8	20.1 ± 12.7	0.894
Hb, g/L	107.1 ± 23.5	104.8 ± 24.0	112.6 ± 21.7	0.138	111.4 ± 23.3	112.2 ± 25.6	110.6 ± 21.4	0.83
PLT count, × 10⁹/L	139.7 ± 80.4	144.8 ± 79.1	126.9 ± 83.6	0.321	142.0 ± 80.5	146.6 ± 71.3	137.3 ± 90.4	0.715
PT (s)	14.9 ± 3.2	15.0 ± 3.5	14.8 ± 2.4	0.768	14.6 ± 1.7	14.8 ± 1.5	14.4 ± 1.9	0.484
aPTT (s)	30.6 ± 8.2	30.5 ± 8.7	30.6 ± 7.1	0.976	30.3 ± 6.0	31.2 ± 6.0	29.5 ± 5.9	0.369
Serum ALB, g/L	34.6 ± 5.9	34.0 ± 6.1	36.0 ± 5.1	0.133	36.5 ± 6.2	36.1 ± 7.3	37.0 ± 5.1	0.674
Serum total bilirubin, mmol/L	16.6 ± 13.3	15.8 ± 13.6	18.6 ± 12.5	0.357	16.4 ± 10.1	15.8 ± 10.5	16.9 ± 10.0	0.724

Table 1. Baseline Characteristics of Patients Before and After PSM

Variables

Before PSM

After PSM

Total (n = 98)

RCA (n = 70)

NA (n = 28)

Total (n = 42)

RCA (n = 21)

NA (n = 21)

ALB: albumin; AKI: acute kidney injury; APACHE II: Acute Physiology and Chronic Health Evaluation II; aPTT: activated partial thromboplastin time; GCS: Glasgow Coma Scale; Hb: hemoglobin; NA: no anticoagulation; PLT: platelet; PSM: propensity score matching; PT: prothrombin time; RCA: regional citrate anticoagulation.

Male

69 (70.4)

49 (70)

20 (71.4)

0.889

33 (78.6)

16 (76.2)

17 (81)

> 0.99

Age, years

53.0 ± 14.5

52.5 ± 13.0

54.2 ± 17.9

0.603

53.5 ± 16.7

51.5 ± 14.6

55.4 ± 18.8

0.461

APACHE II score

28.3 ± 4.5

27.9 ± 4.5

29.2 ± 4.5

0.213

28.4 ± 3.2

28.8 ± 3.0

28.0 ± 3.4

0.448

GCS score

3.0 ± 1.8

3.2 ± 2.0

2.6 ± 1.2

0.146

2.8 ± 1.1

2.7 ± 1.0

2.8 ± 1.3

0.791

Mechanical ventilation

86 (87.8)

62 (88.6)

24 (85.7)

0.738

40 (95.2)

20 (95.2)

> 0.99

Neurologic disease

0.429

0.156

Traumatic brain injury

35 (35.7)

27 (38.6)

8 (28.6)

15 (35.7)

7 (33.3)

8 (38.1)

Intracerebral hemorrhage

39 (39.8)

25 (35.7)

14 (50)

21 (50.0)

13 (61.9)

8 (38.1)

Subarachnoid hemorrhage

4 (4.1)

4 (5.7)

0 (0)

Other categories

20 (20.4)

14 (20)

6 (21.4)

6 (14.3)

1 (4.8)

5 (23.8)

Post craniocerebral operation

74 (75.5)

55 (78.6)

19 (67.9)

0.265

30 (71.4)

15 (71.4)

> 0.99

Comorbidity

Hypertension

50 (51.0)

34 (48.6)

16 (57.1)

0.443

24 (57.1)

11 (52.4)

13 (61.9)

0.533

Diabetes

23 (23.5)

14 (20)

9 (32.1)

0.2

11 (26.2)

4 (19)

7 (33.3)

0.292

Use of osmotic diuretics

83 (84.7)

61 (87.1)

22 (78.6)

0.353

36 (85.7)

18 (85.7)

> 0.99

AKI

70 (71.4)

46 (65.7)

24 (85.7)

0.048

33 (78.6)

16 (76.2)

17 (81)

> 0.99

AKI stage

0.003

0.616

AKI stage 1

39 (39.8)

30 (42.9)

9 (32.1)

16 (38.1)

8 (38.1)

AKI stage 2

20 (20.4)

13 (18.6)

7 (25.0)

10 (23.8)

6 (28.6)

4 (19.0)

AKI stage 3

11 (11.2)

3 (4.3)

8 (28.6)

7 (16.7)

2 (9.5)

5 (23.8)

Urine volume, mL

3,415.1 ± 1,776.0

3,514.0 ± 1,715.4

3,167.8 ± 1,929.5

0.386

3,502.2 ± 1,684.6

3,597.8 ± 1,593.8

3,406.6 ± 1,805.1

0.718

Serum sodium, mmol/L

171.7 ± 8.9

172.3 ± 9.4

170.4 ± 7.7

0.349

171.2 ± 8.4

170.2 ± 9.3

172.1 ± 7.6

0.472

Total calcium, mmol/L,

2.3 ± 0.2

0.304

2.3 ± 0.2

2.4 ± 0.3

2.3 ± 0.2

0.523

Serum creatinine, µmol/L,

176.3 ± 127.2

147.8 ± 95.7

247.8 ± 165.2

< 0.001

205.3 ± 132.4

195.2 ± 113.1

215.3 ± 151.5

0.629

Serum urea, mmol/L

17.4 ± 11.3

16.5 ± 11.3

19.8 ± 11.1

0.191

20.3 ± 11.2

20.5 ± 9.8

20.1 ± 12.7

0.894

Hb, g/L

107.1 ± 23.5

104.8 ± 24.0

112.6 ± 21.7

0.138

111.4 ± 23.3

112.2 ± 25.6

110.6 ± 21.4

0.83

PLT count, × 10⁹/L

139.7 ± 80.4

144.8 ± 79.1

126.9 ± 83.6

0.321

142.0 ± 80.5

146.6 ± 71.3

137.3 ± 90.4

0.715

PT (s)

14.9 ± 3.2

15.0 ± 3.5

14.8 ± 2.4

0.768

14.6 ± 1.7

14.8 ± 1.5

14.4 ± 1.9

0.484

aPTT (s)

30.6 ± 8.2

30.5 ± 8.7

30.6 ± 7.1

0.976

30.3 ± 6.0

31.2 ± 6.0

29.5 ± 5.9

0.369

Serum ALB, g/L

34.6 ± 5.9

34.0 ± 6.1

36.0 ± 5.1

0.133

36.5 ± 6.2

36.1 ± 7.3

37.0 ± 5.1

0.674

Serum total bilirubin, mmol/L

16.6 ± 13.3

15.8 ± 13.6

18.6 ± 12.5

0.357

16.4 ± 10.1

15.8 ± 10.5

16.9 ± 10.0

0.724

**Table 2.** Outcomes of Serum Sodium Reduction Rate and Adverse Events
Variables	Before PSM	After PSM
CRRT: continuous renal replacement therapy; NA: no anticoagulation; PSM: propensity score matching; RCA: regional citrate anticoagulation.
Post CRRT serum sodium, mmol/L	148.6 ± 7.0	147.9 ± 6.8	150.5 ± 7.2	0.094	148.8 ± 7.1	146.8 ± 6.1	150.8 ± 7.6	0.068
Mean hypernatremia correction rates, mmol/L/h	0.5 ± 0.1	0.5 ± 0.1	0.5 ± 0.1	0.587	0.5 ± 0.1	0.5 ± 0.2	0.5 ± 0.1	0.613
CRRT duration, h	49.2 ± 22.5	52.6 ± 22.2	40.8 ± 21.2	0.017	45.9 ± 19.7	49.2 ± 17.6	42.7 ± 21.5	0.291
Adverse events rate, n (%)
Bleeding	14 (14.3)	6 (8.6)	8 (28.6)	0.021	5 (11.9)	0 (0)	5 (23.8)	0.048
Frequent filter clotting	17 (17.3)	0 (0)	17 (60.7)	< 0.001	12 (28.6)	0 (0)	12 (57.1)	< 0.001
Metabolic acidosis	14 (14.3)	9 (12.9)	5 (17.9)	0.534	5 (11.9)	2 (9.5)	3 (14.3)	1
Metabolic alkalosis	13 (13.3)	7 (10)	6 (21.4)	0.186	7 (16.7)	2 (9.5)	5 (23.8)	0.41
Hypocalcemia	5 (5.1)	2 (2.9)	3 (10.7)	0.139	2 (4.8)	1 (4.8)	1 (4.8)	1
Citrate accumulation	6 (6.1)	6 (8.6)	0 (0)	0.178	1 (2.4)	1 (4.8)	0 (0)	1

Table 2. Outcomes of Serum Sodium Reduction Rate and Adverse Events

Variables

Before PSM

After PSM

Total (n = 98)

RCA (n = 70)

NA (n = 28)

P value

Total (n = 42)

RCA (n = 21)

NA (n = 21)

P value

CRRT: continuous renal replacement therapy; NA: no anticoagulation; PSM: propensity score matching; RCA: regional citrate anticoagulation.

Post CRRT serum sodium, mmol/L

148.6 ± 7.0

147.9 ± 6.8

150.5 ± 7.2

0.094

148.8 ± 7.1

146.8 ± 6.1

150.8 ± 7.6

0.068

Mean hypernatremia correction rates, mmol/L/h

0.5 ± 0.1

0.587

0.5 ± 0.1

0.5 ± 0.2

0.5 ± 0.1

0.613

CRRT duration, h

49.2 ± 22.5

52.6 ± 22.2

40.8 ± 21.2

0.017

45.9 ± 19.7

49.2 ± 17.6

42.7 ± 21.5

0.291

Adverse events rate, n (%)

Bleeding

14 (14.3)

6 (8.6)

8 (28.6)

0.021

5 (11.9)

0 (0)

5 (23.8)

0.048

Frequent filter clotting

17 (17.3)

0 (0)

17 (60.7)

< 0.001

12 (28.6)

0 (0)

12 (57.1)

< 0.001

Metabolic acidosis

14 (14.3)

9 (12.9)

5 (17.9)

0.534

5 (11.9)

2 (9.5)

3 (14.3)

Metabolic alkalosis

13 (13.3)

7 (10)

6 (21.4)

0.186

7 (16.7)

2 (9.5)

5 (23.8)

0.41

Hypocalcemia

5 (5.1)

2 (2.9)

3 (10.7)

0.139

2 (4.8)

1 (4.8)

Citrate accumulation

6 (6.1)

6 (8.6)

0 (0)

0.178

1 (2.4)

1 (4.8)

0 (0)

**Table 3.** Comparison of Laboratory Indicators Before and After CRRT (Original Cohort)
Group	Time	Total calcium (mmol/L)	Serum creatinine (µmol/L)	Serum urea (mmol/L)	Hb (g/L)	PLT count (× 10⁹/L)	PT (s)	aPTT (s)	Serum ALB (mmol/L)	Serum total bilirubin (mmol/L)
^aCompared with the NA group before CRRT, P < 0.05. ^bCompared with in this group before CRRT, P < 0.05. ALB: albumin; aPTT: activated partial thromboplastin time; CRRT: continuous renal replacement therapy; Hb: hemoglobin; NA: no anticoagulation; PLT: platelet; PT: prothrombin time; RCA: regional citrate anticoagulation.
RCA (n = 70)	Before CRRT	2.3 ± 0.2	147.8 ± 95.7^a	16.5 ± 11.3	104.8 ± 24.0	144.8 ± 79.1	15.0 ± 3.5	30.5 ± 8.7	34.0 ± 6.1	15.8 ± 13.6
	After CRRT	2.5 ± 0.2^b	100.1 ± 58.2^b	12.1 ± 7.1^b	104.1 ± 21.5	104.6 ± 72.1^b	15.1 ± 3.2	32.3 ± 5.0^b	36.8 ± 5.1^b	18.4 ± 7.5^b
	Difference	−0.1 ± 0.3	16.5 ± 11.3	4.4 ± 8.2	0.8 ± 15.7	40.2 ± 60.6	0.0 ± 3.7	−1.8 ± 8.4	−2.8 ± 6.4	−2.6 ± 14.0
NA (n = 28)	Before CRRT	2.3 ± 0.2	247.8 ± 165.2	19.8 ± 11.1	112.6 ± 21.7	126.9 ± 83.6	14.8 ± 2.4	30.6 ± 7.1	36.0 ± 5.1	18.6 ± 12.5
	After CRRT	2.4 ± 0.2^b	166.8 ± 100.5^b	14.9 ± 6.5^b	106.9 ± 22.8	84.1 ± 54.1^b	14.6 ± 2.4	33.3 ± 7.2^b	36.2 ± 6.1	23.6 ± 14.2^b
	Difference	−0.2 ± 0.3	81.0 ± 113.5	4.9 ± 7.9	5.7 ± 21.3	42.8± 41.7	0.2 ± 2.9	−2.7 ± 8.0	−0.2 ± 7.6	−5.0 ± 12.9

Table 3. Comparison of Laboratory Indicators Before and After CRRT (Original Cohort)

Group

Time

Total calcium (mmol/L)

Serum creatinine (µmol/L)

Serum urea (mmol/L)

Hb (g/L)

PLT count (× 10⁹/L)

PT (s)

aPTT (s)

Serum ALB (mmol/L)

Serum total bilirubin (mmol/L)

^aCompared with the NA group before CRRT, P < 0.05. ^bCompared with in this group before CRRT, P < 0.05. ALB: albumin; aPTT: activated partial thromboplastin time; CRRT: continuous renal replacement therapy; Hb: hemoglobin; NA: no anticoagulation; PLT: platelet; PT: prothrombin time; RCA: regional citrate anticoagulation.

RCA (n = 70)

Before CRRT

2.3 ± 0.2

147.8 ± 95.7^a

16.5 ± 11.3

104.8 ± 24.0

144.8 ± 79.1

15.0 ± 3.5

30.5 ± 8.7

34.0 ± 6.1

15.8 ± 13.6

After CRRT

2.5 ± 0.2^b

100.1 ± 58.2^b

12.1 ± 7.1^b

104.1 ± 21.5

104.6 ± 72.1^b

15.1 ± 3.2

32.3 ± 5.0^b

36.8 ± 5.1^b

18.4 ± 7.5^b

Difference

−0.1 ± 0.3

16.5 ± 11.3

4.4 ± 8.2

0.8 ± 15.7

40.2 ± 60.6

0.0 ± 3.7

−1.8 ± 8.4

−2.8 ± 6.4

−2.6 ± 14.0

NA (n = 28)

Before CRRT

2.3 ± 0.2

247.8 ± 165.2

19.8 ± 11.1

112.6 ± 21.7

126.9 ± 83.6

14.8 ± 2.4

30.6 ± 7.1

36.0 ± 5.1

18.6 ± 12.5

After CRRT

2.4 ± 0.2^b

166.8 ± 100.5^b

14.9 ± 6.5^b

106.9 ± 22.8

84.1 ± 54.1^b

14.6 ± 2.4

33.3 ± 7.2^b

36.2 ± 6.1

23.6 ± 14.2^b

Difference

−0.2 ± 0.3

81.0 ± 113.5

4.9 ± 7.9

5.7 ± 21.3

42.8± 41.7

0.2 ± 2.9

−2.7 ± 8.0

−0.2 ± 7.6

−5.0 ± 12.9

**Table 4.** Comparison of Laboratory Indicators Before and After CRRT (Matched Cohort)
Group	Time	Total calcium (mmol/L)	Serum creatinine (µmol/L)	Serum urea (mmol/L)	Hb (g/L)	PLT count (× 10⁹/L)	PT (s)	aPTT (s)	Serum ALB (mmol/L)	Serum total bilirubin (mmol/L)
^bCompared with in this group before CRRT, P < 0.05. ALB: albumin; aPTT: activated partial thromboplastin time; CRRT: continuous renal replacement therapy; Hb: hemoglobin; NA: no anticoagulation; PLT: platelet; PT: prothrombin time; RCA: regional citrate anticoagulation.
RCA (n = 21)	Before CRRT	2.4 ± 0.3	195.2 ± 113.1	20.5 ± 9.8	112.2 ± 25.6	146.6 ± 71.3	14.8 ± 1.5	31.2 ± 6.0	36.1 ± 7.3	15.8 ± 10.5
	After CRRT	2.5 ± 0.2	122.5 ± 72.4^b	14.3 ± 6.3^b	112.1 ± 22.9	118.3 ± 90.2^b	15.2 ± 2.2	34.8 ± 5.3^b	37.5 ± 4.7	19.8 ± 7.3^b
	Difference	−0.1 ± 0.3	72.7 ± 51.1	6.1 ± 7.4	0.1 ± 11.4	28.2 ± 53.0	−0.5 ± 3.0	−3.6 ± 6.8	−1.3 ± 6.2	−3.9 ± 10.7
NA (n = 21)	Before CRRT	2.3 ± 0.2	215.3 ± 151.5	20.1 ± 12.7	110.6 ± 21.4	137.3 ± 90.4	14.4 ± 1.9	29.5 ± 5.9	37.0 ± 5.1	16.9 ± 10.0
	After CRRT	2.5 ± 0.3	134.4 ± 73.6^b	14.1 ± 6.5^b	107.6 ± 21.5	88.9 ± 56.6^b	14.6 ± 2.5	34.0 ± 8.1^b	37.1 ± 6.2	21.8 ± 10.6^b
	Difference	−0.2 ± 0.3	80.9 ± 92.7	6.2 ± 6.9	3.0 ± 21.3	48.5 ± 45.2	−0.2 ± 2.5	−4.5 ± 7.4	−0.2 ± 7.7	−4.9 ± 11.9

Table 4. Comparison of Laboratory Indicators Before and After CRRT (Matched Cohort)

Group

Time

Total calcium (mmol/L)

Serum creatinine (µmol/L)

Serum urea (mmol/L)

Hb (g/L)

PLT count (× 10⁹/L)

PT (s)

aPTT (s)

Serum ALB (mmol/L)

Serum total bilirubin (mmol/L)

^bCompared with in this group before CRRT, P < 0.05. ALB: albumin; aPTT: activated partial thromboplastin time; CRRT: continuous renal replacement therapy; Hb: hemoglobin; NA: no anticoagulation; PLT: platelet; PT: prothrombin time; RCA: regional citrate anticoagulation.

RCA (n = 21)

Before CRRT

2.4 ± 0.3

195.2 ± 113.1

20.5 ± 9.8

112.2 ± 25.6

146.6 ± 71.3

14.8 ± 1.5

31.2 ± 6.0

36.1 ± 7.3

15.8 ± 10.5

After CRRT

2.5 ± 0.2

122.5 ± 72.4^b

14.3 ± 6.3^b

112.1 ± 22.9

118.3 ± 90.2^b

15.2 ± 2.2

34.8 ± 5.3^b

37.5 ± 4.7

19.8 ± 7.3^b

Difference

−0.1 ± 0.3

72.7 ± 51.1

6.1 ± 7.4

0.1 ± 11.4

28.2 ± 53.0

−0.5 ± 3.0

−3.6 ± 6.8

−1.3 ± 6.2

−3.9 ± 10.7

NA (n = 21)

Before CRRT

2.3 ± 0.2

215.3 ± 151.5

20.1 ± 12.7

110.6 ± 21.4

137.3 ± 90.4

14.4 ± 1.9

29.5 ± 5.9

37.0 ± 5.1

16.9 ± 10.0

After CRRT

2.5 ± 0.3

134.4 ± 73.6^b

14.1 ± 6.5^b

107.6 ± 21.5

88.9 ± 56.6^b

14.6 ± 2.5

34.0 ± 8.1^b

37.1 ± 6.2

21.8 ± 10.6^b

Difference

−0.2 ± 0.3

80.9 ± 92.7

6.2 ± 6.9

3.0 ± 21.3

48.5 ± 45.2

−0.2 ± 2.5

−4.5 ± 7.4

−0.2 ± 7.7

−4.9 ± 11.9

**Table 5.** Univariate and Multivariable Cox Regression Analyses of the Risk Factors of the First Filter Lifespan (Original Cohort)
Variables	Univariate analysis	Multivariable analysis
Note: The multivariable Cox proportional hazards model was constructed by including all variables with a P-value < 0.05 in the univariate analysis (i.e., RCA, hypertension, use of osmotic diuretics, AKI, serum sodium, and serum creatinine). The variance inflation factor (VIF) for each covariate in the final model was < 5, indicating no significant multicollinearity. AKI: acute kidney injury; CI: confidence interval; HR: hazard ratio; RCA: regional citrate anticoagulation.
RCA (yes vs. no)	0.19	0.11–0.31	< 0.001	0.09	0.05–0.18	< 0.001
Hypertension (yes vs. no)	2.08	1.29–3.35	0.003	2.49	1.46–4.26	0.001
Use of osmotic diuretics (yes vs. no)	2.19	1.00–4.78	0.05	3.27	1.39–7.67	0.007
AKI (yes vs. no)	2.22	1.23–3.98	0.008	1.36	0.69–2.66	0.371
Serum sodium	0.96	0.93–0.99	0.006	0.96	0.93–0.99	0.013
Serum creatinine	1.002	1.0005–1.0039	0.012	1.00	0.99–1.00	0.007

Table 5. Univariate and Multivariable Cox Regression Analyses of the Risk Factors of the First Filter Lifespan (Original Cohort)

Variables

Univariate analysis

Multivariable analysis

95% CI

P value

95% CI

P value

Note: The multivariable Cox proportional hazards model was constructed by including all variables with a P-value < 0.05 in the univariate analysis (i.e., RCA, hypertension, use of osmotic diuretics, AKI, serum sodium, and serum creatinine). The variance inflation factor (VIF) for each covariate in the final model was < 5, indicating no significant multicollinearity. AKI: acute kidney injury; CI: confidence interval; HR: hazard ratio; RCA: regional citrate anticoagulation.

RCA (yes vs. no)

0.19

0.11–0.31

< 0.001

0.09

0.05–0.18

< 0.001

Hypertension (yes vs. no)

2.08

1.29–3.35

0.003

2.49

1.46–4.26

0.001

Use of osmotic diuretics (yes vs. no)

2.19

1.00–4.78

0.05

3.27

1.39–7.67

0.007

AKI (yes vs. no)

2.22

1.23–3.98

0.008

1.36

0.69–2.66

0.371

Serum sodium

0.96

0.93–0.99

0.006

0.96

0.93–0.99

0.013

Serum creatinine

1.002

1.0005–1.0039

0.012

1.00

0.99–1.00

0.007

**Table 6.** Comparison of Hospitalization Before and After PSM
Variables	Before PSM	After PSM
ICU: intensive care unit; NA: no anticoagulation; PSM: propensity score matching; RCA: regional citrate anticoagulation.
Days in ICU	19.5 ± 16.1	21.0 ± 17.5	15.7 ± 11.7	0.146	15.9 ± 10.6	16.4 ± 11.5	15.3 ± 10.0	0.732
Costs in hospital, yuan	229,919.7 ± 213,678.5	258,761.0 ± 240,991.8	157,816.6 ± 89,807.1	0.034	192,082.6 ± 138,796.6	228,431.1 ± 168,930.5	155,734.1 ± 90,444.3	0.09
In-hospital mortality	18 (18.4)	10 (14.3)	8 (28.6)	0.099	9 (21.4)	2 (9.5)	7 (33.3)	0.13
Mortality on 28 days	63 (64.3)	42 (60)	21 (75)	0.162	31 (73.8)	16 (76.2)	15 (71.4)	0.726

Table 6. Comparison of Hospitalization Before and After PSM

Variables

Before PSM

After PSM

Total (n = 98)

RCA (n = 70)

NA (n = 28)

P value

Total (n = 42)

RCA (n = 21)

NA (n = 21)

P value

ICU: intensive care unit; NA: no anticoagulation; PSM: propensity score matching; RCA: regional citrate anticoagulation.

Days in ICU

19.5 ± 16.1

21.0 ± 17.5

15.7 ± 11.7

0.146

15.9 ± 10.6

16.4 ± 11.5

15.3 ± 10.0

0.732

Costs in hospital, yuan

229,919.7 ± 213,678.5

258,761.0 ± 240,991.8

157,816.6 ± 89,807.1

0.034

192,082.6 ± 138,796.6

228,431.1 ± 168,930.5

155,734.1 ± 90,444.3

0.09

In-hospital mortality

18 (18.4)

10 (14.3)

8 (28.6)

0.099

9 (21.4)

2 (9.5)

7 (33.3)

0.13

Mortality on 28 days

63 (64.3)

42 (60)

21 (75)

0.162

31 (73.8)

16 (76.2)

15 (71.4)

0.726