Low-molecular-weight heparin (LMWH) does not appear to reduce the risk of symptomatic venous thromboembolism (VTE) among hospitalized older patients, according to research presented at the International Society of Thrombosis and Haemostasis (ISTH) 2023 Congress.

There has been conflicting evidence thereafter about whether to use thromboprophylaxis in hospitalized patients, suggesting that further study is needed.

To help clarify this issue, researchers designed the randomized, phase 3 SYMPTOMS trial (ClinicalTrials.gov Identifier: NCT02379806) to determine what groups, if any, of hospitalized patients benefit from LMWH for the reduction of symptomatic VTE risk. The primary endpoint was symptomatic confirmed VTE and/or fatal or nonfatal pulmonary embolism at 30 days.

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Overall, 1541 patients were enrolled and randomly assigned to receive LMWH (enoxaparin; 1278 patients) or placebo (1263 patients). In the LMWH and placebo groups, the median ages were 82 and 81 years, respectively, 40% and 40.9% of patients were male sex, and 20.3% and 22.6% of patients had been admitted to hospital because of an acute infectious disease.

Analysis suggested that patients who received LMWH did not see a reduction in the likelihood of developing a symptomatic confirmed VTE or fatal or nonfatal pulmonary embolism at 30 days (1.8% vs 2.2% with placebo; difference: 0.4; 95% CI, -1.5-0.7). Furthermore, the secondary endpoint of 30-day all-cause mortality was similar in the 2 groups (3.4% with LMWH vs 2.7% with placebo; difference: 0.7; 95% CI, -0.6-2.0).

The rates of major bleeding were also similar in the 2 groups. The study’s presenter stressed, however, that secondary findings from this trial warrant further study in this population.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, or device companies. Please see the original reference for a full list of disclosures.


Mottier D, Girard P, Couturaud F, et al. Prevention of symptomatic venous thromboembolism with low-molecular-weight heparin in hospitalized older adult medical patients: a randomized placebo-controlled trial. ISTH Congress 2023; June 24-28, 2023. Abstract LB 02.2.