Published in:
Open Access 01-12-2015 | Letter
Contradictory findings on one-year mortality following ICU delirium
Published in: Critical Care | Issue 1/2015
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In contrast to prior studies (Table 1), Wolters and colleagues [1] reported no significant association between delirium and 1-year survival among Dutch ICU survivors. The authors attributed this finding to a novel adjustment of their Cox survival model for the sum of patients’ Sequential Organ Failure Assessment (SOFA) scores (obtained three times daily). Hence, we wish to enquire about the results of their multivariable model if re-run without SOFA adjustment: is the adjusted hazard ratio for delirium statistically significant? This contradictory result also could be attributable to other issues, rather than this unique adjustment that combined SOFA score and length of stay, as described below.
Table 1
Selected studies evaluating mortality after ICU delirium
|
Significant association between delirium and mortality
|
No association
|
||||||
|---|---|---|---|---|---|---|---|
|
Ely:
|
Kiely:
|
Pisani:
|
Van Rompaey:
|
Shehabi:
|
Abelha:
|
Wolters:
|
|
|
JAMA
|
JAGS
|
AJRCCM
|
J Clin Nutr
|
Crit Care Med
|
Crit Care
|
Crit Care
|
|
|
Year
|
2004
|
2009
|
2009
|
2009
|
2010
|
2013
|
2014
|
|
Location
|
USA
|
USA
|
USA
|
Netherlands
|
5 countries
|
Portugal
|
Netherlands
|
|
Study population
|
224 ventilated MICU and CCU patients
|
412 ICU survivors with delirium at discharge
|
304 MICU patients
|
105 non-intubated ICU patients
|
354 ventilated ICU patients
|
562 SICU patients with non-emergency surgery
|
1,101 ICU patients
|
|
Patient characteristics at admission
|
|||||||
|
Age (mean (sd))
|
Del = 56 (17)
|
84 (7)
|
75 (9)
|
62
|
62 (15)
|
Median (IQR)
|
60 (17)
|
|
No del = 54 (17)
|
Del = 65 (54-74)
|
||||||
|
No del = 64 (53-73)
|
|||||||
|
Severity of illness (mean (sd))
|
APACHE II
|
NR
|
APACHE II minus CNS component
|
APACHE II
|
APACHE II
|
Median (IQR)
|
APACHE IV
|
|
Del = 26(8)
|
Del = 26(8)
|
19 (7)
|
APACHE II
|
61 (29)
|
|||
|
No del = 23(10)
|
22 (6)
|
No del = 23(10)
|
Del = 9 (7-12)
|
||||
|
No del = 8 (5-10)
|
|||||||
|
ICU mortality
|
13%
|
NR
|
16%
|
7%
|
NR
|
1%
|
13%
|
|
ICU LOS (median (IQR))
|
NR
|
NR
|
5
|
Del = 13.4
|
Del = 16 (7 - 23)
|
Del = <1 (<1–3)
|
Del = 8 (5 – 15)
|
|
No del = 2.5
|
No del = 4 (3 - 6)
|
No del = <1 (<1- <1)
|
No del = 3 (2-5)
|
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|
Delirium measure
|
Binary; time-dependent
|
Persistence; time-varying
|
Days; time-varying
|
Binary
|
0,1,2, ≥3 days
|
Binary
|
Binary
|
|
Mortality assessment
|
|||||||
|
Time (months)
|
6
|
12
|
12
|
3 and 6
|
1
|
6
|
12
|
|
Mortality in ICU survivors
|
NR
|
39%
|
41%
|
11% (3 mo)
|
NR
|
13%
|
18%
|
|
12% (6 mo)
|
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|
Model
|
Cox survival
|
Discrete time survival
|
Cox survival
|
Logistic
|
Cox survival
|
Logistic
|
Cox survival
|
|
Results (95% CI)
|
HR = 3.2
|
HR = 2.9
|
HR = 1.1
|
OR 3 and 6 mo:
|
HR 1,2, ≥3 versus
|
OR = 2.6
|
HR = 1.26
|
|
(1.4-7.7)
|
(1.9-4.4)
|
(1.02-1.18)
|
4.3 (1.3-14.7)
|
0 days:
|
(1.4-4.8)
|
(0.93-1.71)
|
|
|
3.8 (1.1-13.1)
|
1.7 (1.3-2.3)
|
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|
2.7 (1.6-4.6)
|
|||||||
|
3.7 (1.9-7.2)
|
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