Excess body weight is not independently associated with outcome in mechanically ventilated patients with acute lung injury.

BACKGROUND: Despite an epidemic of obesity among adults, the effect of excess body weight on outcome from critical illness is not well studied. OBJECTIVE: To examine the association between excess body weight and outcome in mechanically ventilated patients with acute lung injury. DESIGN: Secondary analysis of participants in trials of therapy for acute lung injury. SETTING: 10 U.S. medical centers that participate in the National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome Network. PATIENTS: 902 mechanically ventilated patients who were enrolled in randomized, controlled trials of therapy for acute lung injury. INTERVENTION: Assignment to higher (12 mL/kg of predicted weight) or lower (6 mL/kg of predicted weight) tidal volume ventilation strategies with specified weaning protocols. Some patients also received ketoconazole, lisofylline, or placebo by factorial design. MEASUREMENTS: Mortality rate, rate of unassisted ventilation by day 28, and number of ventilator-free days. RESULTS: Indirect causes of lung injury, including trauma, were more common in obese patients. Overweight and obese patients had higher peak and plateau airway pressures before enrollment because of higher set tidal volumes. After risk adjustment, excess body weight was not associated with death, achievement of unassisted ventilation, or number of ventilator-free days. This lack of effect persisted with categorical or continuous measures of body mass index (BMI). We found no significant interaction between ventilator protocol assignment and BMI category. CONCLUSIONS: After risk adjustment, overweight and obese patients with acute lung injury have outcomes similar to those of patients with normal BMI. The lack of interaction between ventilator protocol assignment and BMI suggests that patients with normal, overweight, or obese BMI benefit from lower tidal volume ventilation for acute lung injury.

Gender, age, and heart failure with preserved left ventricular systolic function.

OBJECTIVES: This study was designed to determine if women are more likely than men to have heart failure (HF) with preserved systolic function after adjustment for potential confounders, including age. BACKGROUND: Although prior evidence suggests an independent association between female gender and preserved left ventricular systolic function (LVSF) in patients with HF, existing studies are limited by referral biases, small sample sizes, or the inability to adjust for a wide range of potential confounding variables. METHODS: This is a cross-sectional study using data from retrospective medical chart abstraction of a national sample of Medicare beneficiaries hospitalized with the principal discharge diagnosis of HF in acute-care nongovernmental hospitals in the U.S. between April 1998 and March 1999. Patients were eligible for this analysis if they were age 65 years or older, had documentation of LVSF, and corroboration of the diagnosis of HF. We used multivariable logistic regression to identify the correlates of preserved LVSF, which was defined as qualitatively normal function or quantitatively reported ejection fraction > or =0.50. Stratified regressions by gender were performed to identify significant interactions. RESULTS: Of the 19,710 patients in the analysis, preserved LVSF was present in 6,700 (35%), 79% of whom were women. In contrast, among the 12,956 patients with impaired LVSF, only 49% were women. Patients with preserved LVSF were 1.5 years older than those with impaired LVSF. After adjustment for age and other patient factors, female gender remained strongly associated with preserved LVSF (calculated risk ratio = 1.71; 95% confidence interval 1.63 to 1.78). The association was consistent in all age groups, and was similar in patients with or without coronary artery disease, hypertension, pulmonary disease, renal insufficiency, or atrial fibrillation. CONCLUSIONS: In elderly patients hospitalized with HF, preserved systolic function is primarily a condition of women, independent of important demographic and clinical characteristics.