DVT: prophylaxis: 40 mg enoxaparin od was most effective at preventing DVT during hip replacement.

Clinical bottom line (level 1b)

  1. Patients who undergo hip replacement and were given 40 mg od or 30 mg bd enoxaparin, were less likely to have a DVT post-op than those given 10 mg od (NNT = 8 at 7 days) .
  2. There was no clear difference in the risk of a major bleed with a higher dose of enoxaparin.
  3. There were no clear differences between 40 mg od and 30 mg bd.
Spiro et al: Annals of Internal Medicine 1994; 121 (2): 81-89
Expires May 2003

The study

Double-blinded concealed randomised trial with intention-to-treat
Setting: 32 centres, USA

568 patients (aged mean 65 years, 63% male) undergoing hip replacement

Excluded if
  • <31 years old
  • DVT diagnosed on IPG or ultrasound 14 days before surgery
  • women with child-bearing potential
  • ipsilateral hip surgery within three months
  • history of DVT or PE
  • heparin-associated thrombocytopenia
  • haemorrhagic disorder
  • allergy to heparin/protamine or contrast media
  • surgery to eye or nervous system within three months
  • acute GI ulceration
  • uncontrolled hypertension
  • use of NSAIDs within four days before surgery


    • Control Group: (n = 161, 161 analysed): enoxaparin 10 mg sc od
    Experimental Group: (n = 199, 199 analysed): enoxaparin 40 mg sc od
    Experimental Group: (n = 208, 208 analysed): enoxaparin 30 mg sc every 12 hours

    100% followed for 7 days
    Outcome notes:
    • major bleed : overt bleed and one of: death or life-threatening event; acute MI/stroke; retroperitoneal or intracranial haemorrhage; transfused two or more units of blood; fall in haemoglobin of two or more g/dl

    The evidence

    enoxaparin 10 mg versus 40 mg or 30 mg
    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    DVT 7 days 40
    (25%)    		 49
    (12%)    		 52%
    (29% to 67%)    		 12.8%
    (5.42% to 20.2%)    		 8
    (5 to 18)
    major bleed 7 days 3
    (1.9%)    		 18
    (4.4%)    		 -140%
    (-700% to 29%)    		 -2.56%
    (-5.45% to 0.33%)    		 -39
    (NNT = 302 to infinity;
    NNH = 18 to infinity)
    death 7 days 0
    (0%)    		 2
    (0.49%)    		 -inf%
    (-75% to - inf%)    		 -0.49%
    (-1.17% to 0.19%)    		 -204
    (NNT = 530 to infinity;
    NNH = 85 to infinity)

    enoxaparin 40 mg od versus 30 mg bd
    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    DVT 7 days 27
    (13.6%)    		 22
    (10.6%)    		 22%
    (-32% to 54%)    		 2.99%
    (-3.34% to 9.32%)    		 33
    (NNT = 11 to infinity;
    NNH = 30 to infinity)
    major bleed 7 days 7
    (3.5%)    		 11
    (5.3%)    		 -50%
    (-280% to 41%)    		 -1.77%
    (-5.75% to 2.20%)    		 -56
    (NNT = 45 to infinity;
    NNH = 17 to infinity)
    death 7 days 2
    (1.0%)    		 0
    (0%)    		 100%
    (% to %)    		 1.01%
    (-0.38% to 2.39%)    		 100
    (NNT = 42 to infinity;
    NNH = 263 to infinity)

    Comments

    1. As dose increases, DVT risk reduces and bleeding risk increases. 40 mg od seems to be the optimum dose.

    Citation

    1. Spiro TE, Johnson GJ, Christie MJ, et al: Efficacy and safety of enoxaparin to prevent deep venous thrombosis after hip replacement surgery. Annals of Internal Medicine 1994; 121 (2): 81-89
    Contributor: Chris Ball and Clare Wotton, May 2000
    Reviewer:

    Clinical Question.
    Patient undergoing hip replacement
    Intervention or Exposure enoxaparin
    Outcome DVT and death