Assessment of bleeding risk in low-weight patients receiving prophylactic subcutaneous unfractionated heparin.

BACKGROUND: Underweight patients may be at an increased risk of bleeding while receiving venous thromboembolism (VTE) prophylaxis. Additional evidence is needed to identify patient-specific factors associated with bleeding. The objective of the study was to describe the incidence and identify risk factors associated with bleeding in low-weight (⩽ 60 kg) adult patients receiving subcutaneous unfractionated heparin (SQH) for VTE prophylaxis. METHODS: This was a single-center, retrospective, nested case-control study of low-weight patients receiving SQH for VTE prophylaxis for ⩾ 48 hours. Cases, patients with clinically relevant bleeding while receiving SQH, and controls, patients without a bleeding event, were matched in a 1:3 ratio for age, sex, primary service (surgical or medical), and time at risk of bleeding on SQH to determine factors associated with bleeding. RESULTS: A total of 3761 patients met the inclusion criteria, of which 38 cases of clinically relevant bleeding were identified. The bleeding incidence was 1% at hospital day 6 and 2.8% at hospital day 14. Most patients in this study (69%) received SQH 5000 units three times daily. ICU admission at SQH start was associated with bleeding, OR 2.97 (95% CI 1.21-7.29). CONCLUSION: Bleeding in low-weight patients on prophylactic SQH was uncommon. Patients admitted to the ICU at time of SQH start may be at a higher risk of bleeding. Further studies are needed to detect additional risk factors associated with bleeding and investigate the effects of reduced dosing in this population.

Leptin alters energy intake and fat mass but not energy expenditure in lean subjects.

Based on studies in mice, leptin was expected to decrease body weight in obese individuals. However, the majority of the obese are hyperleptinemic and do not respond to leptin treatment, suggesting the presence of leptin tolerance and questioning the role of leptin as regulator of energy balance in humans. We thus performed detailed novel measurements and analyses of samples and data from our clinical trials biobank to investigate leptin effects on mechanisms of weight regulation in lean normo- and mildly hypo-leptinemic individuals without genetic disorders. We demonstrate that short-term leptin administration alters food intake during refeeding after fasting, whereas long-term leptin treatment reduces fat mass and body weight, and transiently alters circulating free fatty acids in lean mildly hypoleptinemic individuals. Leptin levels before treatment initiation and leptin dose do not predict the observed weight loss in lean individuals suggesting a saturable effect of leptin. In contrast to data from animal studies, leptin treatment does not affect energy expenditure, lipid utilization, SNS activity, heart rate, blood pressure or lean body mass.