Association Between Baseline Driving Pressure and Mortality in Very Old Patients with Acute Respiratory Distress Syndrome

<b>Rationale:</b> Because of the effects of aging on the respiratory system, it is conceivable that the association between driving pressure and mortality depends on age. <b>Objectives:</b> We endeavored to evaluate whether the association between driving pressure and mortality of patients with acute respiratory distress syndrome (ARDS) varies across the adult lifespan, hypothesizing that it is stronger in older, including very old (⩾80 yr), patients. <b>Methods:</b> We performed a secondary analysis of individual patient-level data from seven ARDS Network and PETAL Network randomized controlled trials ("ARDSNet cohort"). We tested our hypothesis in a second, independent, national cohort ("Hellenic cohort"). We performed both binary logistic and Cox regression analyses including the interaction term between age (as a continuous variable) and driving pressure at baseline (i.e., the day of trial enrollment) as the predictor and 90-day mortality as the dependent variable. <b>Measurements and Main Results:</b> On the basis of data from 4,567 patients with ARDS included in the ARDSNet cohort, we found that the effect of driving pressure on mortality depended on age (<i>P</i> = 0.01 for the interaction between age as a continuous variable and driving pressure). The difference in driving pressure between survivors and nonsurvivors significantly changed across the adult lifespan (<i>P</i> < 0.01). In both cohorts, a driving pressure threshold of 11 cm H₂O was associated with mortality in very old patients. <b>Conclusions:</b> Data from randomized controlled trials with strict inclusion criteria suggest that the effect of driving pressure on the mortality of patients with ARDS may depend on age. These results may advocate for a personalized age-dependent mechanical ventilation approach.