The objective of the study is to compare the safety of innohep® and Unfractionated Heparin (UFH) in terms of clinically relevant bleedings in elderly patients with impaired renal function for initial treatment of acute Deep Venous Thrombosis (DVT).

The primary response criterion is the percentage of patients with clinically relevant bleeding events prior to day 90 +/- 5.

Inclusion Criteria:

• Patients with a symptomatic and objectively confirmed Venous Thromboembolism (VTE) (lower limb deep venous thrombosis (DVT) or pulmonary embolus (PE)) with mandatory presences of objectively confirmed and treatment requiring DVT, i.e. symptomatic and objectively confirmed distal DVT or objectively confirmed, symptomatic or asymptomatic proximal DVT (confirmation of DVT should be performed by ultrasonography or venography within 48 hous prior to randomisation)
• Patients with an indication for DVT treatment with SC Low Molecular Weight Heparin (LMWH) or Unfractionated Heparin (UFH) followed by Oral Anticoagulant (OAC) for at least 90 days
• Hospitalized patients who, during SC anticoagulant treatment, will be followed, as specified in the protocol, on a daily basis either in the hospital or in an out-patient setting
• Patients at or above 75 years with a creatinine clearance less than or equal to 60 mL/min calculated according to the Cockcroft-Gault formula
• Patients at or above 70 years with a creatinine clearance less than or equal to 30 mL/min calculated according to the Cockcroft-Gault formula

Exclusion Criteria:

• Patients receiving high dose (i.e. equivalent to a dose recommended for treatment of DVT) of UFH or LMWH or thrombolytic agents within the last 4 weeks except for UFH/LMWH during the last 36 hours prior to randomisation
• Patients on oral anticoagulant treatment (vitamin K-antagonists) at or within last 1 week prior to randomisation
• Patients with a symptomatic venous thromboembolism (VTE) requiring thrombolytic therapy or invasive intervention
• End stage renal disease patients requiring dialysis
• Surgery within 2 weeks prior to randomisation or planned surgery, epidural anaesthesia and/or spinal anaesthesia during the SC anticoagulant treatment period
• Planned use of acetylsalicylic acid in doses above 300 mg/day, NSAID or Dextran 40 at randomisation and during the SC anticoagulant treatment period
• Patients with a current overt bleeding or known haemorrhage condition (e.g. active G.I. ulcer)
• Patients with a platelet count < 100 x 10 9/L
• Patients with a known history of heparin-induced thrombocytopenia
• Patients with known severe hepatic insufficiency manifested as international normalized ratio (INR) greater than or equal to 1.5
• Patients with uncontrolled severe hypertension i.e. a systolic blood pressure > 220 mm Hg or diastolic blood pressure > 120 mm Hg during at least 2 measurements within 24 hours prior to randomisation
• Patients with ischaemic stroke at or within last 1 week prior to randomisation
• Patients with a known haemorrhagic stroke within 3 months prior to randomisation
• Patients with known bacterial endocarditis within 3 months prior to randomisation

Five patients who did not receive any study treatment were excluded from the safety analysis set. Three patients randomised to the Heparin group received innohe® during all their SC treatment period by mistake. These three patients were accounted for with respect to the trial medication actually taken, i.e. innohep®, in the safety analysis set.