Incidence and Outcomes of Contrast-Induced AKI Following Computed Tomography

Article Figures & Data

Table 1.

Patient demographic and clinical characteristics

Demographics	Overall (n = 421)	Inpatient (n = 127)	Outpatient (n = 294)	P
age (yr)	69 ± 10	70 ± 10	69 ± 10	0.5
male	403 (96)	121 (95)	282 (96)	0.8
white	385 (91)	114 (90)	271 (92)	0.5
black	31 (7)	11 (9)	20 (7)	0.5
Comorbid illnesses
diabetes mellitus	172 (41)	60 (47)	112 (38)	0.09
liver disease	59 (14)	20 (16)	39 (13)	0.5
congestive heart failure	68 (16)	30 (24)	38 (13)	0.01
peripheral vascular disease	54 (13)	19 (15)	35 (12)	0.4
cerebrovascular disease	45 (11)	23 (18)	22 (7)	<0.01
Baseline renal function
serum creatinine (mg/dl)	1.4 (1.3, 1.5)	1.4 (1.3, 1.5)	1.4 (1.3, 1.5)	1.0
eGFR (ml/min per 1.73 m²)	53 (48, 57)	52 (49, 56)	53 (48, 57)	0.7
eGFR 30–59 ml/min per 1.73 m²	421 (100)	127 (100)	294 (100)	1.0
eGFR 15–29 ml/min per 1.73 m²	0 (0)	0 (0)	0 (0)	NC
eGFR <15 ml/min per 1.73 m²	0 (0)	0 (0)	0 (0)	NC
Preexisting medication use
nonsteroidal anti-inflammatories	40 (10)	11 (9)	29 (10)	0.9
loop diuretics	101 (24)	36 (28)	65 (22)	0.2
angiotensin converting enzyme inhibitors	161 (38)	42 (33)	119 (40)	0.2
theophylline	2 (0.5)	1 (1.0)	1 (0.3)	0.5

eGFR, estimated glomerular filtration rate; NC, not calculable. Data are n (%), mean ± SD, or median (interquartile range).

Table 2.

Use of preventive care

	Overall (n = 421)	Inpatient (n = 127)	Outpatient (n = 294)	P
Intravenous fluid use
Preprocedure	84 (20)	62 (49)	22 (7)	<0.01
Postprocedure	91 (22)	70 (55)	21 (7)	<0.01
Preprocedure and postprocedure	70 (17)	53 (42)	17 (6)	<0.01
N-acetylcysteine use	73 (17)	48 (38)	25 (9)	<0.01
Discontinuation of non-steroidal anti-inflammatories^a	0 (0)	0 (0)	(0) 0	—
Instructed to increase oral fluids	74 (18)	33 (26)	41 (14)	<0.01
Complied with increase in oral fluids^b	59 (80)	28 (82)	31 (76)	0.4

Table 3.

Incidence of contrast-induced acute kidney injury

CIAKI definition	Overall (n = 367)	Inpatient (n = 119)	Outpatient (n = 248)	P^b
All patients
≥ 25%	24 (6.5)	15 (12.6)	9 (3.6)	0.001
≥ 50%^a	2 (0.5)	1 (0.8)	1 (0.4)	0.6
≥ 100%	(0) 0	0 (0)	0 (0)	—
≥ 0.25 mg/dl	40 (10.9)	21 (17.6)	19 (7.7)	0.004
≥ 0.5 mg/dl	13 (3.5)	8 (6.7)	5 (2.0)	0.2
≥ 1.0 mg/dl	1 (0.3)	0 (0)	1 (0.4)	0.5
eGFR ≤ 45 ml/min per 1.73 m²	n = 51	n = 15	n = 36
≥ 25%	6 (11.8)	2 (13.3)	4 (11.1)	0.8
≥ 50%^a	1 (2.0)	0 (0)	1 (2.8)	0.5
≥ 100%	0 (0)	0 (0)	0 (0)	—
≥ 0.25 mg/dl	7 (13.7)	2 (13.3)	5 (13.9)	0.9
≥ 0.5 mg/dl	5 (9.8)	2 (13.3)	3 (8.3)	0.6
≥ 1.0 mg/dl	1 (2.0)	0 (0)	1 (2.8)	0.5
eGFR > 45 ml/min per 1.73 m²	n = 316	n = 104	n = 212
≥ 25%	18 (5.7)	13 (12.5)	5 (2.4)	<0.001
≥ 50%^a	1 (0.3)	1 (1)	0 (0)	0.2
≥ 100%	0 (0)	0 (0)	0 (0)	—
≥ 0.25 mg/dl	33 (10.4)	19 (18.3)	14 (6.6)	0.001
≥ 0.5 mg/dl	8 (2.5)	6 (5.7)	2 (0.9)	0.01
≥ 1.0 mg/dl	0 (0)	0 (0)	0 (0)	—

eGFR, estimated glomerular filtration rate; —, not applicable. Data are n (%).
↵^a The 2 patients meeting this definition of CIAKI also met criteria for RISK category of acute kidney injury as defined by RIFLE criteria.
↵^b Comparison of CIAKI between inpatients and outpatients.

Table 4.

Associations of patient and procedural factors with the development of CIAKI

Patient factor	Odds of CIAKI (↑ Scr ≥ 25%)	Odds of CIAKI (↑ Scr ≥0.5 mg/dl)
Age >65 yr	1.0 (0.4, 2.4)	1.1 (0.3, 3.7)
Diabetes mellitus	1.4 (0.6, 3.1)	1.2 (0.4, 3.5)
Congestive heart failure	2.4 (1.0, 5.9)	4.1 (1.3, 12.7)
Peripheral vascular disease	2.4 (0.9, 6.4)	2.1 (0.5, 7.8)
Cerebrovascular disease	1.3 (0.4, 4.4)	0.7 (0.1, 5.6)
Scr > 1.5 mg/dl	2.5 (1.1, 5.9)	5.7 (1.8, 17.8)
eGFR ≤ 45 ml/min per 1.73 m²	2.1 (0.8, 5.6)	4.0 (1.3, 12.7)
Hematocrit < 35%	1.8 (0.8, 4.3)	2.6 (0.8, 7.9)
Inpatient status	3.8 (1.6, 9.0)	3.5 (1.1, 10.9)
Procedure factors
Contrast (iso-osmolal)	0.5 (0.2, 1.3)	0.9 (0.2, 4.4)
Dose contrast > 100 ml	3.3 (1.0, 11.5)	2.5 (0.6, 11.7)
Preprocedure and postprocedure IV fluid	1.6 (0.6, 4.1)	0.8 (0.2, 3.8)
N-acetylcysteine use	2.4 (1.9, 5.8)	2.0 (0.6, 6.7)

Table 5.

Association of contrast-induced acute kidney injury with mortality

Definition of CIAKI based on Δ Scr	Unadjusted OR for death^a	95% CI	Adjusted OR for death^b	95% CI
≥ 25%	3.8	0.4–20.6	2.2	0.2–14.6
≥ 50%	NC	—	—	—
≥ 100%	NC	—	—	—
≥ 0.25 mg/dl	2.1	0.2–11.0	1.7	0.1–10.9
≥ 0.5 mg/dl	7.7	0.7–45.9	4.8	0.4–39.5
≥ 1.0 mg/dl	NC	—	—	—

OR, odds ratio; CI, confidence interval; NC, not calculable (because of absence of deaths); —, not applicable.
↵^a ORs are based on comparisons of patients who did and did not develop CIAKI.
↵^b Adjusted for status at time of procedure and cerebrovascular disease.