Table 1
Summary of important studies looking at haematological parameters in COVID – 19 patients. (aPTT - Activated Partial Thromboplastin time, FDP – Fibrin degradation products, PT – Prothrombin Time)
| Authors | Sample Size (n) | Haematological Abnormalities (%) | Key Features |
|---|---|---|---|
| Chen et al. [29] | 99 | Elevated D-dimer - 36 (36%) Thrombocytopenia – 12 (12%) Prolonged aPTT – 6 (6%) Prolonged PT – 5 (5%) | The first study to report both the clinical and laboratory features of COVID-19 related illness. |
| Wang et al. [30] | 138 (ICU – 36, Non-ICU – 102) | Prolonged PT – 80 (58%) Elevated D-dimer - (26% of the patients from ICU) | 1 – The levels of D-dimer were significantly higher in ICU patients than non-ICU patients. (p<0.001) 2 – The levels of D-dimer were significantly higher in non-survivors than survivors. (p<0.05) 3 – D-dimer levels showed an increasing trend in patients who succumbed to the illness. |
| Zhou et al. [31] | 191 (Survivors -137, Non-survivors – 54) | Elevated D-dimer Survivors – 67 (57%) Non-survivors – 50 (92%) | 1 – A D-dimer level of >1.0 μg/mL at admission was associated with higher odds of mortality. OR=18.42 (p=0.0033) 2 – D-dimer levels were significantly higher in non-survivors than in survivors. (5.2 vs. 0.6, p<0.0001) |
| Huang et al. [32] | 41 (ICU – 13, Non-ICU – 28) | - | 1- Median D-dimer levels were significantly higher in ICU patients as compared to the non-ICU patients. (2.4 vs. 0.5, p=0.0042) 2 – Median prothrombin time was significantly higher in ICU patients as compared to the non-ICU patients. (12.2sec vs. 10.7sec, p=0.012) |
| Chen et al. [33] | 21 (Severe cases – 11, Moderate cases – 10) | - | Compared to moderate cases, severe cases had significantly elevated levels of D-dimer. (2.6 vs. 0.3, p=0.029) |
| Guan et al. [9] | 1099 | Elevated D-dimer 260/560 (46.4%) | D-dimer levels were significantly elevated in a higher proportion of patients with severe illness than those with non-severe illness. (59.6 % vs. 43.2 %, p = 0.0021) |
| Han et al. [34] | 94 patients 40 healthy controls | - | 1- D-dimer levels were significantly higher in the patient group than the healthy control group. (10.36 vs. 0.26, p<0.001) 2 – FDP levels were significantly higher in patients than in controls. (33.83 vs. 1.55mg/L, p<0.001) 3- Higher D-dimer and FDP levels were found to be predictive of severe disease. |
| Li et al [35] | 279 (Ordinary - 136 Improved - 23 Poor- 120) | - | The D-dimer levels on admission were significantly higher in the improved and poor group of patients than ordinary patients. (p<0.01) |
| Ordinary – Mild disease, subsidedImproved – First deteriorated, then improved gradually with treatment Poor – Deteriorated or died | |||
| Tang et al. [12] | 183 (Survivors – 162, Non-survivors – 21) | - | Abnormal coagulation tests (Elevated D-dimer, FDPs and decreased fibrinogen) were associated with a poorer prognosis, i.e. these parameters were significantly deranged in non-survivors than the survivors. |
Table 2
Summary of the interim guidelines published by some of the societies and forums. (aPTT – Activated Partial Thromboplastin Time, DOAC – Direct Oral Anticoagulant, ESC – European Society of Cardiology, ISTH – International Society on Thrombosis and Haemostasis, LMWH – Low Molecular Weight Heparin, VTE – Venous Thromboembolism)
| Society/Forum | Recommendations |
|---|---|
| European Society of Cardiology (ESC) [25] | 1 – All admitted patients with COVID-19 related illnesses should get, at the least, prophylactic dose of enoxaparin (40mg daily). 2 - Depending on the clinical features, a patient at a high risk of thromboembolism should receive therapeutic dose anticoagulation. It can be in the form of a heparin drip (per parenteral protocol) or enoxaparin (1mg/kg twice a day) based on whether the patient is in the intensive care unit or not. 3 - Patients at low risk of thromboembolism are further classified based on the D-dimer levels. A) D-dimer <0.5 μg/mL = Prophylactic dose anticoagulation (Enoxaparin 40mg/day) B) D-dimer 0.5 to 3.0 μg/mL = Enoxaparin 40mg twice a day C) D-dimer >3.0 μg/mL = Enoxaparin 1mg/kg twice a day 4 - The patients at high risk of thromboembolism and having markedly elevated D-dimer (>3.0 μg/mL) should undergo a point-of-care ultrasound. Based on its results, a call should be on whether to continue therapeutic dose or switch to prophylactic dose anticoagulation. |
| International society of thrombosis and haemostasis (ISTH) on the management of coagulopathy [26] | 1 - Patients having one/more of the following should be admitted to the hospital. A) Markedly raised D-dimer (>3-4 times of the normal) B) Prolonged prothrombin time C) Platelet count of <100 × 109/L D) Fibrinogen concentration <2.0 g/L 2 - All admitted patients, in the absence of contraindications - should receive prophylactic dose anticoagulation (LMWH). |
| Scientific and standardization committee by ISTH - guidance on prevention and treatment of VTE [27] | 1 - Universal routine thromboprophylaxis should be given in all admitted patients of COVID-19 related illnesses. (LMWH as preferred agent) 2 - Dose should be modified appropriately in patients with renal failure and obesity as required. 3 - Intermediate dose anticoagulation can be a reasonable option in patients admitted to ICU with COVID-19 related illnesses. 4 - Extended post-discharge thromboprophylaxis should be considered in patients that are a high risk of thromboembolism. The duration can be up to 30 days post-discharge. |
| Interim clinical guidance from the anticoagulation forum [28] | 1 - All hospitalized patients, with COVID-19 related illnesses, should receive prophylactic anticoagulation. 2 - Escalated dose anticoagulation should be considered in critically ill (ICU) patients. 3 - To monitor the anticoagulant activity of heparin, an anti-factor-Xa assay should be used in place of aPTT as the baseline aPTT may be abnormal in some COVID-19 patients. 4 – Post-discharge VTE prophylaxis may be considered on a case-to-case basis in COVID -19 patients that have one/more of the following- A) Prolonged ICU stay B) Paralyzed for a long time C) Risk factor for VTE at the time of discharge (Decreased mobility, severe weakness) 5 – All pregnant patients of COVID-19 should receive prophylactic dose anticoagulation for the prevention of VTE. 6 – Patients on vitamin K antagonists (warfarin) should be transitioned to directly acting oral anticoagulants (DOACs), except for indications like mechanical heart valves, antiphospholipid antibody syndrome. |