Table 2.
Characteristics of Studies Reporting on Prevalence or Incidence of VTE in Patients With COVID-19
| Source | Study Design | Country | No. of Participating Centers | Peer-Review | Patient Selection | Thromboprophylaxis | Sample Size (ICU/Ward) | Age (y) | DVT Screening | Outcome Adjudication |
|---|---|---|---|---|---|---|---|---|---|---|
| Cui et al4 | Retrospective cohort | China | 1 | Yes | Unclear | No | 81/NA | Mean, 60 | Yes | NR |
| Klok et al6,7 | Retrospective cohort | The Netherlands | 3 | Yes | Consecutive ICU admissions | Nadroparin (weight-adjusted prophylactic dose)a | 184/NA | Mean, 64 | No | NR |
| Helms et al5 | Prospective cohort | France | 2 | Yes | Consecutive ICU admissions | 105/150 (70%) prophylactic heparin; 45/150 (30%) therapeutic heparin | 150/NA | Median, 63 | No | NR |
| Ranucci et al25 | Prospective cohort | Italy | 1 | Yes | Unclear | Intermediate-dose nadroparinb | 16/NA | Median, 61 | NR | NR |
| Spiezia et al12 | Prospective cohort | Italy | 1 | Yes | Consecutive ICU admissions | Anticoagulant prophylaxis | 22/NA | Mean, 67 | NR | NR |
| Llitjos et al8 | Retrospective cohort | France | 2 | Yes | Consecutive ICU admissions | 8/26 (31%) prophylactic heparin; 18/26 (69%) therapeutic heparin | 26/NA | Median, 68 | Yes | NR |
| Lodigiani et al9 | Retrospective cohort | Italy | 1 | Yes | Consecutive hospital admissions | 42/61(69%) prophylactic heparin; 17/61 (28%) weight-adjusted prophylactic heparin; 2/61 (3%) therapeutic heparin | 61/327 | Median, 66 | No | NR |
| Poissy et al11 | Retrospective cohort | France | 1 | Yes | Consecutive ICU admissions | NRc | 107/NA | Median, 57 | NR | NR |
| Thomas et al13 | Retrospective cohort | United Kingdom | 1 | Yes | Consecutive ICU admissions | Weight-adjusted heparin at prophylactic dose | 63/NA | Mean, 59 | No | NR |
| Middeldorp et al10 | Retrospective cohort | The Netherlands | 1 | Yes | Consecutive hospital admissions | Nadroparin (weight-adjusted prophylactic dose)d,e | 75/123 | Mean, 61 | Partlyf | Yes |
| Xu et al14 | Retrospective cohort | China | 1 | No | Unclear | Anticoagulant prophylaxis in at-risk populationg | 15/123 | Mean, 52 | Partlyh | NR |
NA = not applicable; NR = not reported. See Table 1 legend for expansion of other abbreviation.
During the study period, the dose of thromboprophylaxis with nadroparin was doubled in 2 of 3 participating centers; 17 of 184 (7.2%) patients were on therapeutic anticoagulation at admission.
Nadroparin 4,000 units twice daily, which was increased to nadroparin 6,000 units twice daily (or 8,000 units twice daily if BMI > 35 kg/m2) in all patients after performance of coagulation and viscoelastic tests.
Of the patients with pulmonary embolism, 20 received prophylactic heparin, 1 therapeutic heparin, and 1 vitamin K antagonist with therapeutic INR at time of diagnosis.
Seven of 75 (9.3%) patients in the ICU and 12 of 123 (10%) patients on the ward continued therapeutic anticoagulation for an indication that was present at time of admission; none of those patients developed a VTE.
During the study period, the dose of thromboprophylaxis with nadroparin was doubled for patients admitted to the ICU.
Screening ultrasound for lower extremity DVT was performed in 38 of 75 (51%) critically ill patients and 17 of 123 (14%) patients on the ward.
Patients with a Padua score ≥ 4 points were considered at risk for VTE; “routine thromboprophylaxis” was given to 15 of 15 (100%) ICU patients and 26 of 123 (21%) ward patients.
Screening ultrasound for lower extremity DVT was performed in all critically ill patients; no screening was performed in patients on the ward.