Association Between Hospitalization for Acute Medical Illness and VTE Risk: A Lower Efficacy of Thromboprophylaxis in Elderly Patients? Results from the Edith Case-Control Study
Bibliographic record
Abstract
Abstract Background: Randomized controlled trials demonstrated that low-molecular-weight heparin (LMWH), unfractionated heparin (UFH), or fondaparinux, are efficient for venous thromboembolism (VTE) prevention in acutely ill medical patients. However, asymptomatic VTE, whose clinical relevance is unknown, represented the vast majority of outcome events of these trials. Objectives: Using a case-control design, we aimed to estimate the association between admission to hospital for acute medical illness, prescription of pharmacological thromboprophylaxis during admission and symptomatic VTE. Methods: 750 symptomatic non-surgical, non-cancer, and non-pregnancy-related VTE cases and their 750 age and sex-matched controls were analyzed. Patients hospitalized for an acute medical illness within three months prior to inclusion in the study were identified, and their hospital charts were reviewed. We considered that patients receiving pharmacological thromboprophylaxis were those prescribed either 1) LMWH at an approved preventive dose; 2) low dose UFH (5000 units bid or tid); or 3) fondaparinux 2.5mg once daily, for at least 6 days. Results: Patients' mean age was 67.2 ± 17.1 years, and 664 (44.3%) were men. A total of 145 cases (19.3%) and 91 controls (12.1%) were hospitalized for acute medical illness at least once in the preceding 3 months prior to inclusion in the study (p<0.001). Hospitalization for acute medical illness in the preceding three months was associated with a 75% increase in VTE risk: OR 1.75 (95% CI: 1.32-2.33). Pharmacological thromboprophylaxis was prescribed in 46.2% of the hospitalized cases (n=67) and in 51.6% of the controls (n=47) (p=0.49). As compared with patients who were not hospitalized, there was a significant 2-fold increased risk of VTE when thromboprophylaxis was not prescribed during hospitalization: OR 2.01 (95% CI: 1.22-3.29), and a non-significant 61% increased risk when thromboprophylaxis was prescribed during hospitalization: OR 1.61 (95% CI: 0.55-1.69). Proportions of admitted patients and prescription of pharmacological thromboprophylaxis are shown in table.Table 1.Age<75Age≥75CasesControlsOR (95% CI)CasesControlsOR (95% CI)No hospitalization365 (83.5%)380 (87.5%)Ref.240 (76.7%)279 (88.3%)Ref.Hospitalization for acute medical illness72 (16.5%)54 (12.5%)1.42 (0.96-2.08)73 (23.3%)37 (11.7%)2.25 (1.46-3.47)- No prescription of pharmacological thromboprophylaxis51 (70.8%)28 (51.9%)2.01 (1.11-3.62)27 (37.0%)16 (43.2%)2.02 (1.01-4.03)- Prescription of pharmacological thromboprophylaxis21 (29.2%)26 (48.1%)0.93 (0.44-1.95)46 (63.0%)21 (56.8%)2.69 (1.28-5.66) In patients <75 years, VTE risk associated with hospitalization for acute medical illness was low and not significant (OR 1.42 (95% CI: 0.96-2.08) as compared with no hospitalization. When pharmacological thromboprophylaxis was not prescribed during admission, there was a significant 2-fold increase in VTE risk associated with hospitalization: OR 2.01 (95% CI: 1.11-3.62), whereas no association was found when thromboprophylaxis was prescribed: OR 0.93 (95% CI: 0.44-1.95). In patients ≥75 years, we observed an overall 2.25-fold increase in VTE risk associated with hospitalization for acute medical illness as compared with no hospitalization: OR 2.25 (95% CI: 1.46-3.47). VTE risk associated with hospitalization remained significant whether or not pharmacological thromboprophylaxis was prescribed during hospitalization: OR 2.69 (95% CI 1.28-5.66) and OR 2.02 (95% CI: 1.01-4.03) respectively. Adjustment for a priori VTE risk stratification of medical hospitalized patients did not modify estimates. Conclusion: Our case-control study suggests that VTE prevention in acutely ill medical patients may be less effective in patients ≥75 years as compared with younger patients. This finding will be addressed in a randomized double blind controlled trial comparing enoxaparin 40mg once daily to placebo for the prevention of symptomatic VTE and fatal PE in patients ≥75 years admitted to hospital for an acute medical illness (NCT02379806). Disclosures No relevant conflicts of interest to declare.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.011 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".