Risk factors for delirium: are therapeutic interventions part of it?

Figures & data

Table 1 Demographics and characteristics of study participants

Characteristics	All patients (n=320)
Age (years), median (IQR)	61 (46–71)
Sex (male), n (%)	187 (58.44)
Education background (senior high school or above), n (%)	98 (30.63)
Medical insurance, n (%)	258 (80.63)
APACHE II at enrollment, median (IQR)	20 (15–23)
Alcohol abuse, n (%)	9 (2.81)
Pre-ICU conditions, n (%)
Cancer	33 (10.31)
Hypertension	95 (29.69)
Diabetes	34 (10.63)
Impaired renal function	20 (6.25)
Type of admission, n (%)
Medical patients	130 (40.63)
Surgical patients	190 (59.38)
Admission diagnoses, n (%)
Asthma/COPD/respiratory failure/ARDS	97 (30.31)
Sepsis	146 (45.63)
MODS	51 (15.94)
CHF, myocardial infarction, arrhythmia	38 (11.88)
Complex trauma	30 (9.38)
Severe acute pancreatitis	29 (9.06)
Cerebrovascular disease	24 (7.50)
Acute renal failure	23 (7.19)
Hypovolemic shock	18 (5.63)
Combined liver failure	17 (5.31)
Acute diffuse peritonitis/gastrointestinal perforation	15 (4.69)
Chronic progressive renal failure	13 (4.06)
Septic shock	12 (3.75)
Eclampsia, amniotic fluid embolism, placental abruption, etc	11 (3.44)
Poisoning	10 (3.12)
Neurologic (status epilepticus, other)	6 (1.88)
Upper airway obstruction	1 (0.31)
Duration of mechanical ventilation (days) median (IQR)	1 (0–3)
ICU length of stay (days), median (IQR)	4 (1–9)
Hospital length of stay (days), median (IQR)	7 (3–13)

Abbreviations: APACHE II, Acute Physiology and Chronic Health Evaluation II; ARDS, adult respiratory distress syndrome; MODS, multiple organ dysfunction syndrome; CHF, congestive heart failure.

Table 2 Comparison of routine risk factors associated with delirium

Variables	No delirium (n=228)	Delirium^# (n=92)	P
Demographics, n (%)
Age, ≥65 years	79 (34.65)	45 (48.91)	0.018
Male	136 (59.6)	51 (55.4)	0.532
Senior high school or above	70 (30.7)	26 (28.3)	0.666
Medical insurance	186 (81.6)	72 (78.3)	0.497
Pre-existing medical condition, n (%)
APACHE II score ≥20 at admission	104 (45.61)	62 (67.39)	<0.001
Hypertension	63 (27.6)	32 (34.8)	0.205
Diabetes	19 (8.33)	15 (16.3)	0.036
Cancer	26 (11.4)	7 (7.61)	0.312
Impaired renal function	8 (3.51)	12 (13.0)	0.001
Private room	122 (53.5)	58 (63.0)	0.12

Notes: ^#Defined as >1 episode of delirium within the ICU days with delirium screening.

Abbreviation: APACHE II, Acute Physiology and Chronic Health Evaluation II.

Table 3 Comparison between delirium group and non-delirium group in terms of interventions

Interventions	No delirium (n=228)	Delirium^# (n=92)	P
Mechanical ventilation	116 (50.9)	80 (87.0)	<0.001
Artificial airway			<0.001
Not use	112 (49.1)	12 (13.0)
Tracheal intubation	107 (46.9)	67 (72.8)
Tracheotomy	9 (3.95)	13 (14.1)
Deep intravenous catheter	63 (27.6)	39 (42.4)	0.01
Drainage tube	100 (43.9)	33 (35.9)	0.189
Invasive artery	137 (60.1)	70 (76.1)	0.007
Gastric tube	105 (46.1)	73 (79.3)	<0.001
Urinary catheter	189 (82.9)	87 (94.6)	0.006
Use of vasoactive drugs	12 (5.26)	14 (15.2)	0.003
Sedative medications	149 (65.4)	85 (92.4)	<0.001

Notes: ^#Defined as >1 episode of delirium within the ICU days with delirium screening. P<0.05, significant difference between the delirium group and non-delirium group. 

Table 4 Multivariate analysis

Variables	Odds ratio	95% confidence interval (CI)	P
Age, ≥65 years	1.664	0.919–3.014	0.093
ICU length of stay	1.067	1.035–1.099	<0.001
Mechanical ventilation	5.123	2.501–10.494	<0.001
Gastric tube	1.935	1.012–3.698	0.046
APACHE II score (≥20)*	1.897	1.045–3.441	0.035
Sedative medications			0.093
Use of vasoactive drugs			0.890
Artificial airway
Not use
Tracheal intubation			0.248
Tracheotomy			0.248
Deep intravenous catheter			0.567
Arterial line			0.801
Urinary catheter			0.355
Diabetes			0.419
Impaired renal function			0.170

Notes: *APACHE II score was calculated as categorical variable including: APACHE II score<20 and APACHE II score ≥20. The analyses were adjusted for age and ICU length of stay.

Abbreviation: APACHE II, Acute Physiology and Chronic Health Evaluation II.

Table 5 Outcomes of delirium

Items	No delirium (n=228)	Delirium^# (n=92)	P
Duration of mechanical ventilation, days, median (IQR)	1 (0–2)	3.5 (1–7.75)	<0.001
ICU length of stay, days, median (IQR)	2 (1–6)	10 (5–24)	<0.001
Hospital length of stay, days, median (IQR)	5.5 (2–10)	12 (6.25–27.25)	<0.001

Notes: ^#Defined as >1 episode of delirium within the ICU days with delirium screening. P<0.05, significant difference between the delirium group and non-delirium group. 

Abbreviation: IQR, interquartile range.