Table 2.

Differences in response to PEEP strategy by phenotype (ALVEOLI cohort)

PEEP Strategy	phenotype-I		phenotype-II		phenotype-III
	Low PEEP (n = 108)	High PEEP (n = 115)	Low PEEP (n = 97)	High PEEP (n = 82)	Low PEEP (n = 68)	High PEEP (n = 79)
60-day mortality	14.8%	22.6%	28.9%	28.1%	35.3%	34.2%
Ventilator-free days	18.0	15.5	12.1	12.3	10.7	11.3
ICU-free days	16.1	14.2	9.9	10.8	9.1	10.4

For test of interaction, 60-day mortality of phenotype-I versus II p = 0.25, phenotype-I versus III p = 0.25, phenotype-II versus III p = 0.99; ventilator-free days (VFD) of phenotype-I versus II p = 0.002, phenotype-I versus III p = 0.001, phenotype-II versus III p = 0.67; ICU-free days (IFD) of phenotype-I versus II p < 0.001, phenotype-I versus III p < 0.001, phenotype-II versus III p = 0.47. VFD: number of days during the 28-day period where patients are both alive and free of mechanical ventilation; IFD: number of days during the 28-day period where patients are both alive and free of ICU care; ALVEOLI, randomized controlled trials of higher versus lower PEEP; PEEP, positive end-expiratory pressure; ICU, intensive care unit