Trends in ICU mortality and underlying risk over three decades among mechanically ventilated patients. A group level analysis of cohorts from infection prevention studies

Hurley, James C.

doi:10.1186/s13613-023-01159-0

Annals of Intensive Care

Table 2 Meta-regression models of mortality incidence^a,b,c,d

From: Trends in ICU mortality and underlying risk over three decades among mechanically ventilated patients. A group level analysis of cohorts from infection prevention studies

	Model 1	Model 2	Model 3	Model 4	Model 5
Factor	Coefficient	Coef.	Coef.	Coef.	Coef.	95% CI	p
Groups from observational studies (reference group)	− 1.28***	− 1.30***	− 1.71***	− 1.89***	− 2·02**	− 2·4 to − 1·6	0·001
Non-decontamination studies
● Control groups	− 0·07	− 0·07	− 0·09	− 0·06	− 0·07	− 0·22 to + 0·07	0.34
● Intervention groups	− 0·11	− 0·12	− 0·13	− 0·09	− 0·11	− 0·25 to + 0·03	0.14
Decontamination studies
● Concurrent control groups	+ 0·19*	+ 0·24**	+ 0·23**	+ 0·26**	+ 0·26**	+ 0·11 to + 0·50	0·009
● Intervention groups	− 0·04	+ 0·06	+ 0·05	+ 0·08	+ 0·07	− 0·11 to + 0·24	0·45
PPAP use^e		− 0·22	− 0·20	− 0·19	− 0·18	− 0·41 to + 0·05	0.13
MV(per point)^f		+ 0·003**	+ 0·003**	+ 0·003**	+ 0·003***	+ 0·001 to + 0·005	0.003
Trauma ICU^g		− 0·36***	− 0·29**	− 0·17	− 0·15	− 0·36 to + 0·06	0.15
Mortality census (late versus ICU)^h	+ 0·50***	+ 0·47***	+ 0·46***	+ 0·44***	+ 0·44***	+ 0·33 to + 0·55	0.001
APACHE II score (per point)ⁱ			+ 0.03***		+ 0·02**	+ 0·01 to + 0·04	0.003
Age (per decade)^j				+ 0.11**	+ 0·09*	+ 0·01 to + 0·17	0.025
Year of publication (per decade)^k	+ 0·01	− 0·01	− 0·01	− 0·01	− 0·01*	− 0·013 to − 0·001	0.038
Origin from systematic review^l	+ 0.07	+ 0.06	+ 0.06	+ 0.06	+ 0.08	− 0·02 to − 0·01	0.14

ICU intensive care unit, MV > 90 more than 90% of patients received mechanical ventilation, PPAP protocolized parenteral antibiotic prophylaxis
^aMeta-regression models four and five based on 397 groups (as group mean age is missing for 16 groups), Meta-regression one to three models include all 413 groups
^bInterpretation. For each model the reference group is the observational study (benchmark) groups and this coefficient equals the difference in logits from 0 (a logit equal to 0 equates to a proportion of 50%; a logit equal to -2.2 equates to a proportion of 10%; a logit equal to -4.6 equates to a proportion of 1%) and the other coefficients represent the difference in logits for groups positive for that factor versus the reference group
^c*p < 0.05; **p < 0.01; ***p < 0.001
^dPPAP is the coefficient for those control or intervention groups receiving protocolized parenteral antibiotic prophylaxis
^eThe coefficient representing the increment per percentage point in group level of mechanical ventilation use above 50%
^fThe coefficient representing the increment for admission to a trauma ICU
^gLate mortality versus ICU mortality [censored at day 21 or before]
^hGroup mean APACHE II score with the coefficient representing the increment for each one-point increase
ⁱGroup mean age with the coefficient representing the increment for a ten-year increase
^jYear of study publication with the coefficient representing the increment for each decade post 1980
^kIncrement for a study abstracted in a systematic review

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