Table 2.

Clinical characteristics of case–control sample

Inpatients with COVID-19VTE-positive
(N=21)
VTE-negative
(N=42)
p-value
Age [mean (SD)]*67 (12)65 (15)0.32
Female sex [n (%)]7 (33)18 (43)0.47
Comorbidities
Cardiovascular disease [n (%)]6 (29)9 (21)0.53
Diabetes [n (%)]8 (38)10 (23)0.23
Pulmonary disease [n (%)]8 (38)9 (21)0.16
Renal disease [n (%)]4 (19)6 (14)0.63
Malignancy [n (%)]4 (19)6 (14)0.63
Immunosuppression [n (%)]2 (10)3 (7)0.74
Admission to critical care [n (%)]6 (29)14 (33)0.70
Laboratory parameters
CRP mg/L [median (IQR)]122 (188)78.5 (101)0.09
White cell count ×109/L [median (IQR)]11.1 (4.6)7.2 (4.5)0.009
Lymphocytes ×109/L [median (IQR)]0.9 (0.7)0.9 (0.6)0.95
D-dimer μg/mL [median (IQR)]4.1 (6.0)1.2 (2.0)<0.001
APTT ratio [median (IQR)]1.1 (0.1)1.2 (0.3)0.72
Fibrinogen g/L [mean (SD)]*6.8 (2.2)6.6 (1.8)0.7
INR [median (IQR)]1.1 (0.2)1.05 (0.1)0.02
  • Sequentially diagnosed patients without VTE diagnosis as of 9 April 2020 were selected as controls at a ratio of 2:1. Three cases without measurements of D-dimer, APTT ratio or fibrinogen were included in the analysis. Control patients were excluded if data was incomplete. Control patients were selected at a ratio of 2:1 swab positive (28) to swab negative (14) to match the distribution of cases. D-dimer above 20 was recorded as 20 for the purposes of analysis. Normally distributed data is marked with an asterisk (*). Proportions were analysed by Z-test, normally distributed variables by unpaired T-test and non-parametric variables by Mann–Whitney test. APTT = activated partial thromboplastin time; CRP = C-reactive protein; INR = international normalised ratio; IQR = interquartile range; SD = standard deviation; VTE = venous thromboembolism.