Does Early Initiation of Continuous Renal Replacement Therapy Affect Outcome: Experience in a Tertiary Care Center

Figures & data

Figure 1. Flow diagram of patients (n = 330) who underwent CRRT from January 1999 to February 2006 at the MC/SJH. Renal recovery defined as the absence of need for dialysis at time of hospital discharge.

Table 1. Baseline demographics and clinical outcomes for patients with acute renal failure requiring CRRT at Marshfield Clinic between 1999 and 2006 (n = 230).

Age, years (mean ± STD)	66.0 ± 14.5; median = 68.8
Male, %	61.3
Baseline BUN, mg/dL (mean ± STD)	63.6 ± 34.2; median = 55.5
Creatinine, mg/dL (mean ± STD)	3.7±1.8; median = 3.5
CCF score (mean ± STD)	9.12 ± 2.8; median = 9.0
Median urine output (mL)
Day 1	400
Day 2	127
Day 3	88
MAP, mmHg (mean ± STD)
Baseline	75.4 ± 11.4
First 72 h after CRRT	77.2 ± 10.5
Median cumulative fluid balance in 72 h (mL)	−2153.5
Pressors at baseline
%	48.84
No (mean ± STD)	0.82 ± 1.00
Renal recovery (%)
For total patients	39.13 (90/230)
For the survivors	71.19 (84/118)
Median survival time (days) for patients who died only	15.5; 95% CI = [12.0, 18.0]
Mortality (%)	48.70 (112/230)
Causes of AKI
Prerenal
Dehydration	34 (14.78%)
Low cardiac output or congestive heart failure	80 (34.78%)
Hepatic disease	13 (5.65%)
Hypoalbuminemia (<2.5 g/dL)	27 (11.74%)
Vascular (renal artery stenosis, vasculitis, peripheral vascular disease)	48 (20.87%)
Glomerular/small vessel	2 (0.87%)
Ischemia/toxin
Ischemia/necrosis (ATNacute tubular necrosis)	61 (26.52%)
Nephrotoxic antibiotics	7 (3.04%)
Nephrotoxic contrast	12 (5.22%)
Nephrotoxic immunosuppression/tumor related	10 (4.35%)
Nephrotoxic other	19 (8.26%)
Pigment related	11 (4.78%)
Interstitial disease	7 (3.04%)
Obstruction	2 (0.87%)

Note: BUN, blood urea nitrogen; CCF, Cleveland Clinic Foundation; MAP, mean arterial pressure; CRRT, continuous renal replacement therapy; AKI, acute kidney injury.

Table 2. Mortality rate, median survival time, and renal recovery rate classified by CCF score.

CCF score		n = 230
1–7	n	66
	CCF median	6.0
	Mortality rate	39.39%
	Median survival time	19.0
	Renal recovery	46.97%
8–12	n	143
	CCF median	10.0
	Mortality rate	48.95%
	Median survival time	38
	Renal recovery	39.16%
13–17	n	21
	CCF median	14.0
	Mortality rate	76.19%
	Median survival time	17.0
	Renal recovery	14.29%

Note: CCF, Cleveland Clinic Foundation.

Table 3. Risk factors for mortality considered and analyzed using univariate analysis.

Risk factors	Odds ratio	p-Value
Ventilator use	3.045	0.0003
Absence of renal recovery	43.636	<0.0001
Palliative care consult	3.038	<0.0001
DNR order	19.121	<0.0001
Hypoalbuminemia (<2.5 g/dL)	3.447	0.0073
Vascular causes for AKI	2.868	0.0023
Laporotomy	4.175	0.0318
Neurological complications	2.321	0.0234
SBP < 100 or MAP < 60	2.366	0.0025
Intubation/mechanical ventilation	3.017	0.0005
Total bilirubin > 2.0 and AST > 25	2.038	0.0205
Vascular failure	2.385	0.0043
Age (≥65)	1.721	0.0476
Gender (male)	0.953	0.8579
Surgery (yes)	2.017	0.0095
BUN at baseline (per 2.72 unit decrease)	1.152	0.4504
Creatinine at baseline (per 2.72 unit decrease)	2.304	0.0022
WBC at baseline	NA	0.6151
MAP mean at baseline	NA	0.4305
MAP mean at D1 CRRT	NA	0.9583
MAP mean at D2 CRRT (per 1 unit decrease)	1.032	0.0081
MAP mean at D3 CRRT (per 1 unit decrease)	1.033	0.0106
ΔMAP over the first 3 CRRT days	0.984	0.3149
Urine output day 1 (≤500)	1.831	0.0314
Urine output day 2 (≤500)	3.357	0.0003
Urine output day 3 (≤500)	2.895	0.0061
Use of vasopressors—baseline	2.250	0.0036
Use of vasopressors—day 1	2.314	0.0025
Use of vasopressors—day 2	2.502	0.0008
Use of vasopressors—day 3	1.897	0.0195
AKI–CRRT (<6 days vs. ≥6 days)	0.198	0.0134
CRRT-day (≥10 days vs. ≤9 days)	2.985	0.0131
CCF_score	1.873	0.0079

Notes: DNR, do not resuscitate; AKI, acute kidney injury; SBP, systolic blood pressure; MAP, mean arterial pressure; BUN, blood urea nitrogen; WBC, white blood cell count; CCF, Cleveland Clinic Foundation; CRRT, continuous renal replacement therapy. ^*indicates urine output more than 500 mL in 24 h.

Table 4. Odds ratio, 95% CI, and p-values for six factors determined from multivariate logistic regression analysis of risk factors for mortality.

Factor	Odds ratio	95% Wald confidence	p-Value
Presence of DNR order	13.06	(4.94, 34.50)	<0.0001
AKI–CRRT (≥6 days vs. <6 days)	11.66	(1.26, 107.91)	0.0305
Neurological complications	7.41	(1.87, 29.35)	0.0043
Use of pressors by third day of CRRT	2.74	(1.07, 7.05)	0.0360
Creatinine at baseline*	3.34	(1.57, 7.10)	0.0018
Absence of renal recovery	60.15	(17.37, 208.31)	<0.0001

Notes: DNR, do not resuscitate; AKI, acute kidney injury; CRRT, continual renal replacement therapy. *Where variable “Creatinine at baseline” had three levels (2 = Creatinine ≤ 2.72, 1 = 2.72 < Creatinine ≤ 5.44, and 0 = Creatinine > 5.44).

Table 5. Logistic regression analysis or nonparametric analysis for renal recovery.

Variable	Odds ratio	95% CI	p-Value
ΔMAP over the first 3 CRRT days	1.022	0.989–1.056	0.1877
Urine output day 1	1.000	1.000–1.001	0.0691
Preserved urine output(%)	1.001	0.999–1.002	0.3998
MAP at baseline	1.004	0.977–1.031	0.7704
Age	0.980	0.962–0.998	0.0300
CCF_score*	0.565	0.353–0.904	0.0172
AKI–CRRT (<6 days vs. ≥6 days)	2.115	0.660–6.778	0.2076
CRRT-day (≤9 days vs. ≥10 days)	1.798	0.755–4.281	0.1852

Notes: MAP, mean arterial pressure; AKI, acute renal failure; CRRT, continuous renal replacement therapy; CCF, Cleveland Clinic Foundation; AKI–CRRT—the time between diagnosis of AKI and initiation of CRRT; CCF_score had three levels (1 = CCF score ≤ 7, 2 = 8 ≤ CCF score ≤ 12, and 3 = CCF score ≥ 13.

*indicates urine output more than 500 mL in 24 h.

Table 6. Cleveland Clinic Foundation (CCF) score calculation methodology.

Variable	Odds ratio (mortality)	Score (1–17)
Male sex	2.4	2
Mechanical ventilation	2.5	3
Platelets < 50 K/L, leukocytes <2.5 K/L, or bleeding diathesis	2.1	3
Absence of surgery during admission	2.0	1
Number of organ failures^a
1	1.0	0
2–3	1.3	2
4–7	2.5	3
Change in blood urea nitrogen^b
0–50 mg/dL	1.8	1
>50 mg/dL	2.0	2
Change in creatinine^b
>5 mg/dL	1.0	0
2–5 mg/dL	2.6	1
≤2 mg/dL	4.8	3

Notes: ^aCardiac failure; systolic blood pressure less than 100 mmHg requiring volume or pressors; respiratory failure; requiring mechanical ventilation; hematologic failure; platelets less than 50 K, leukocytes less than 2.5 K, or bleeding diathesis; gastrointestinal failure; cholecystitis, gastrointestinal bleeding requiring transfusion, necrotizing enterocolitis, or pancreatitis; liver failure bilirubin level greater than 2 mg/dL and aspartate aminotransferase level greater than 25 IU/L; vascular failure; abdominal or thoracic aneurysm, ischemic limb.

^bChange in blood urea nitrogen or creatinine level from admission to the day of dialysis initiation.

Table 7. Odds ratio (OR), 95% confidence interval (CI), and p-values for two factors determined from multivariate logistic regression analysis of renal recovery.

Factor	OR	95% Wald CI	p-Value
Age	0.975	0.957–0.994	0.0109
CCF score	0.510	0.315–0.828	0.0064

Note: CCF, Cleveland Clinic Foundation.