Effects of long-term therapy with either heparin or low-molecular-weight heparin on serum lipid levels. A prospective study.

Beside the anticoagulant and antithrombotic activity, heparin also exerts a lipolytic activity. In a prospective study on patients with venous thromboembolism and some contraindications to coumarin therapy, a low-molecular-weight heparin (Fragmin) was compared to unfractioned (UF) heparin in terms of both efficacy and safety. A secondary aim was to study the influence of both types of heparin on serum lipid levels. Sixty-six consecutive patients who were not taking concomitant treatment with lipid-lowering drugs entered the study. Patients received treatment with either UF heparin, 10,000 IU s.c., b.d., or Fragmin 5,000 IU anti-factor Xa s.c., b.d. for a period of 3 or 6 months, according to whether the initial diagnosis was deep venous thrombosis or pulmonary embolism. Each patient was followed up at 6-weekly intervals, and blood samples were obtained at discharge, and then 6 and 12 weeks after discharge. Finally, a further sample was obtained 3 months after therapy was discontinued. Total cholesterol levels increased significantly in both groups of patients: levels increased from 193 +/- 56 to 246 +/- 63 mg/dl in the UF heparin group (p < 0.001), and from 189 +/- 53 to 222 +/- 47 mg/dl in the Fragmin group (p < 0.05). The increase was mostly due to a very strong increase in HDL cholesterol levels in patients receiving UF heparin (from 46 +/- 12 to 71 +/- 23 mg/dl; p < 0.000005). Three months after discharge, HDL cholesterol levels were significantly higher in patients taking UF heparin than in patients in Fragmin (p = 0.006). By contrast, patients on Fragmin exhibited a significant increase in LDL cholesterol levels: from 112 +/- 39 to 139 +/- 37 mg/dl; p < 0.01.