Abstract
BACKGROUND: The relationship between obesity (defined as body mass index [BMI] ≥ 30 kg/m(2)) and mortality in venous thromboembolism remains controversial. OBJECTIVES: We aimed to compare outcomes after pulmonary embolism (PE) between patients with obesity and nonobese, nonunderweight patients. METHODS: Using a multicenter registry of prospectively recorded individual patient data, we compared outcome rates using multivariable logistic or Cox regression for 30-day and 6-month outcomes respectively (etiologic analysis). We assessed the incremental value of adding BMI information on top of the 30-day European Society of Cardiology (ESC) prognostic algorithm (prognostic analysis). RESULTS: We included 2390 patients with BMI of ≥18.5 kg/m(2) (mean age, 66.9 ± 16.8 years; 1188 men [49.7%]); 686 patients [28.7%] were in the obese group. Mortality rates were significantly lower in patients with obesity than that in patients who were nonobese at 30 days (3.2% [95% CI, 2.0-4.8] vs 5.9% [95% CI, 4.8-7.1]), and 6 months (8.1% [95% CI, 6.2-10.4] vs 16.3% [95% CI, 14.6-18.1]). Rates of secondary nonfatal outcomes (including bleeding, recurrent venous thromboembolism, myocardial infarction, and stroke) did not differ between groups. The addition of the obesity information on top of the ESC prognostic model improved global model fit and discriminatory (Harrell C index from 0.636 to 0.657; P = .07) and calibration capacities (P (Hosmer-Lemeshow) = .02 vs .13), yielding significant reclassification (ie, 10.3%) based on the observed mortality rates with the ESC model as reference. Findings were confirmed in an external validation using 35,796 patients with PE from the RIETE registry. CONCLUSION: We present evidence indicating lower early- and mid-term mortality after PE in patients classified as obese based on BMI, compared with nonobese, nonunderweight patients. BMI should likely be incorporated into algorithms or scoring systems for predicting early mortality following PE.