Objective: The adipocytokine leptin is an independent cardiovascular risk factor and exerts prothrombotic effects, both in arterial and venous thrombosis. We therefore investigated the relationship between leptin levels and clinical outcome in patients with acute pulmonary embolism (PE).
Design: We prospectively studied consecutive patients with confirmed acute PE admitted at the University Hospital of Goettingen (Germany) between 2003 and 2009.
Subjects: The study subjects were a total of 264 patients with PE (median age, 68 years; interquartile range, 53-75; 60% women; body mass index (BMI) 27 kg m(-2) (24.1-31.2)). Leptin levels were determined by a commercially available enzyme-linked immunosorbent assay. Patients were followed for an adverse 30-day outcome, that is, death, circulatory collapse with need for catecholamines, intubation or resuscitation, and for long-term survival.
Results: The median leptin level was 10.1 ng ml(-1) (3.7-25.2). Patients (n=49; 18.6%) with a complicated 30-day course had significantly lower leptin levels (5.3 ng ml(-1) (1.8-19.7) compared with patients without complications (10.4 ng ml(-1) (4.7-25.5), P=0.02). When leptin was analyzed as a continuous variable, there was a significant 36% increase in the relative risk for early complications for every decrease in the natural logarithm of leptin by one s.d. (odds ratio (OR) 1.36 (1.06-1.76), P=0.017), independently of BMI (BMI-adjusted OR, 1.52 (1.13-2.05), P=0.006). In addition, patients within the lowest leptin tertile had a 2.8- and 2.3-fold increased risk for 30-day-complications, compared with those in the middle (P=0.011) and high tertile (P=0.030), and a worse probability of long-term survival (log-rank; P=0.018).
Conclusion: Low plasma leptin concentration is a predictor for a complicated course and high mortality in patients with acute PE. This association is independent of known factors affecting leptin levels, including gender and obesity.