Factors associated with bleeding in elderly hospitalized patients treated with enoxaparin sodium : a prospective, open-label, observational study.

BACKGROUND

Despite a lack of clear recommendations to guide decision-making, reductions in enoxaparin sodium dosage in the elderly and in patients with mild and moderate renal dysfunction are common in patients with acute coronary syndrome.

OBJECTIVE

To evaluate whether weight, age and renal function are associated with anti-factor Xa activity and with bleeding in elderly patients treated with enoxaparin sodium.

METHOD

This was a prospective observational study of 156 elderly patients admitted consecutively to a general internal medicine ward with creatinine clearance >30 mL/min who were treated with enoxaparin sodium twice daily. Anti-factor Xa activity and bleeding events were documented in all patients. Statistical analyses were conducted to determine the effects of clinical characteristics such as renal dysfunction, age and bodyweight on these parameters.

RESULTS

156 patients (60% males, mean age 71.0 +/- 15.98 years) were studied. Therapeutic anti-factor Xa was observed in 85.3% of patients treated with enoxaparin sodium 0.61-0.8 mg/kg/12h, and in 82.6% of patients treated with enoxaparin sodium 0.81-1.1 mg/kg/12h. Minor or major bleeding was observed in 5.8% of patients, and was associated with a lower mean bodyweight (61.89 +/- 13.35 vs 74.30 +/- 13.24 kg for patients with no bleeding; p = 0.014). Bodyweight < or =55 kg was associated with bleeding with an odds ratio of 5.63 (95% CI 1.2, 25, p = 0.025).

CONCLUSION

Low bodyweight is associated with a greater risk of bleeding despite a reduction in enoxaparin sodium dose according to weight. This finding supports the possibility that low bodyweight is an independent risk factor for enoxaparin sodium-related bleeding.