Acute Medical Illness: Advanced Age Alone Predicts Venous Thromboembolism Similar to Existing Risk Assessment Models

Advanced age alone might be an alternative to complex models in predicting venous thromboembolism among medical inpatients.

Takeaway

• Padua, Caprini and International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) risk assessment models (RAMs) had poor discriminating ability to predict venous thromboembolism (VTE) in acutely ill medical inpatients.

• Findings from this secondary analysis of PREVENU study suggest that none of these RAMs provided a better prediction than advanced age alone.
• Using an age above 70 years might be the easiest and most practical way of identifying medical inpatients requiring thromboprophylaxis.

Why This Matters

• International consensus is lacking on criteria for thromboprophylaxis in medical inpatients.

• A strategy based on age alone is easily implementable in regular clinical practice.

Study Design

• This retrospective study included 14,910 patients (median age, 73 years) from Prevenu trial who were hospitalised for acute medical illnesses in a medical ward for at least 2 days.

• Critically ill patients were excluded.
• The primary aim was to assess the global discriminatory power of the RAMs in predicting VTE in comparison with advanced age alone.
• The secondary aim was to compare the incidence of VTE between low- and high-risk patients and assess the robustness of primary results.
• Patients with a Padua score ≥4, Caprini score ≥3, IMPROVE score ≥2 (intermediate and high risk) and IMPROVE score ≥4 (high risk) were considered at an increased risk for VTE.
• Advanced age was defined as reaching 70 years, as defined in the Padua score.
• Funding: None.

Key Results

• Overall, 1.8% of patients experienced symptomatic VTE during follow-up.

• The median time until VTE occurrence was 22 (interquartile range, 10-46) days.
• The area under curve (AUC) of predicting VTE was 0.61 (95% CI, 0.58-0.64) for advanced age alone.
• None of the 3 RAMs had a significantly different AUC compared with advanced age alone for predicting VTE (P=0.284):
  • Padua: 0.64 (95% CI, 0.61-0.67);
  • IMPROVE: 0.63 (95% CI, 0.60-0.66); and
  • Caprini: 0.60 (95% CI, 0.57-0.63).
• In low-risk patients, VTE incidence was 0.6%, 0.5%, 1.0%, 1.6% and 1.2%, according to Padua, Caprini, IMPROVE intermediate-high score, IMPROVE high score and advanced age, respectively.
• In high-risk patients, VTE incidence was 2.2%, 1.9%, 2.5%, 3.0% and 2.3% according to Padua, Caprini, IMPROVE intermediate-high score, IMPROVE high score and advanced age, respectively.
• Global performances were poor for 3 RAMs and advanced age (Youden Index for all, <0.25%).
• After excluding patients who received anticoagulant prophylaxis during their hospital stay, the AUC of predicting VTE was 0.66 (95% CI, 0.62-0.70) for advanced age and not significantly different for the RAMs (P=0.266).

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MAT-BH-2300402/v1/Jun 2023