THE IMPACT OF GENDER ON OUTCOME FROM MECHANICAL VENTILATION

Objective: To determine the relation of gender to outcome for patients requiring mechanical ventilation. Design: A prospective cohort study. Setting: Medical and surgical ICUs in two university-affiliated teach ing hospitals. Patients: Three hundred fifty-seven patients requiring mechanical ventilation.Interventions: Prospective patient surveillance and data collection. Measurements and results: The primary outcome me asure was hospital mortality. Secondary outcome measures included need for reintubation, hospital and ICU length of stay, duration of mechan ical ventilation, and hospital charges, The hospital mortality rate fo r women (n=189) was significantly. greater than the hospital mortality rate for men (n=168) (28.0% vs 17.3%; p=0.016). This difference in ho spital mortality was observed despite similar baseline demographic cha racteristics, severity of illness, indications for mechanical ventilat ion, and number of dysfunctional organ systems in these two groups of patients. The duration of mechanical ventilation and ICU length of sta y was also significantly longer for female patients compared with male patients (p less than or equal to 0.056). In a logistic-regression an alysis, female gender was found to be independently associated with ho spital mortality (adjusted odds ratio [AOR]=2.38; 95% confidence inter val [CI]=1.70 to 3.35; p=0.010). The presence of ARDS (AOR=10.69; 95% CI=5.86 to 19.51; p <0.001), the number of dysfunctional organ systems (AOR=2.07; 95% CI=1.78 to 2.41; p <0.001), acute Physiology and Chron ic Health Evaluation (APACHE) II predicted mortality (AOR=1.15; 95% CI =1.11 to 1.19; p <0.001), and patient age (AOR=1.04; 95% CI=1.03 to 1. 06; p <0.001) were also found to be independently associated with hosp ital mortality. The number of dysfunctional organ systems present at t he start of mechanical ventilation was the major independent predictor of hospital mortality (54% of total explanatory power). Patient gende r was the least important independent predictor of hospital mortality (5% of total explanatory power). Conclusions: In this patient cohort, women requiring mechanical ventilation were at greater risk for hospit al mortality than men. Physicians should be aware that outcome differe nces according to gender can occur when evaluating or designing clinic al trials involving mechanically ventilated patients, Future studies a re necessary to determine the general applicability of these findings and to identify explanations for such observed gender-specific differe nces in outcome.