Venous thromboembolism and COVID-19: a single center experience from an academic tertiary referral hospital of Northern Italy

Preliminary evidence supports the notion that COVID-19 patients may have an increased susceptibility to develop venous thromboembolism (VTE). However, the magnitude of this association still needs to be defined. Furthermore, clinical predictors of thrombogenesis, and the relationship with the inflammatory status are currently unknown. On this basis, we conducted a retrospective, observational study on 259 consecutive COVID-19 patients admitted to an academic tertiary referral hospital in Northern Italy between March 19th and April 6th, 2020. Records of COVID-19 patients with a definite VTE event were reviewed for demographic information, co-morbidities, risk factors for VTE, laboratory tests, and anticoagulation treatment. Twenty-five cases among 259 COVID-19 patients developed VTE (9.6%), all of them having a Padua score > 4, although being under standard anticoagulation prophylaxis since hospital admission. In the VTE subcohort, we found a significant positive correlation between platelet count (PLT) and either C reactive protein (CRP) (p < 0.0001) or lactate dehydrogenase (LDH) (p = 0.0013), while a significant inverse correlation was observed between PLT and mean platelet volume (p < 0.0001). Platelet-to-lymphocyte ratio significantly correlated with CRP (p < 0.0001). The majority of VTE patients was male and younger compared to non-VTE patients (p = 0.002 and p = 0.005, respectively). No significant difference was found in d-dimer levels between VTE and non VTE patients, while significantly higher levels of LDH (p = 0.04) and IL-6 (p = 0.04) were observed in VTE patients in comparison to non-VTE patients. In conclusion, our findings showed a quite high prevalence of VTE in COVID-19 patients. Raised inflammatory indexes and increased serum levels of pro-inflammatory cytokines should raise the clinical suspicion of VTE.