Incidence and outcomes of splanchnic vein thrombosis after diagnosis of COVID-19 or COVID-19 vaccination: a systematic review and meta-analysis.

Coronavirus disease 2019 (COVID-19) and COVID-19 vaccination may cause splanchnic vein thrombosis (SVT), which is potentially fatal. The present study aims to pool the incidence and outcomes of SVT patients with COVID-19 or having received COVID-19 vaccines. The PubMed, EMBASE, and Cochrane databases were searched. Based on the data from cohort studies, meta-analyses were performed to evaluate the incidence of SVT in COVID-19 patients or people having received COVID-19 vaccines. Pooled proportions were calculated. Based on the individual data from case reports, logistic regression analyses were performed to identify factors associated with death in SVT patients. Odds ratios (ORs) were calculated. Among 654 papers initially identified, 135 were included. Based on 12 cohort studies, the pooled incidence of SVT in COVID-19 patients was 0.6%. Data were insufficient to estimate the incidence of SVT after COVID-19 vaccination. Based on 123 case reports, the mortality was 14% (9/64) in SVT patients with COVID-19 and 25% (15/59) in those who received COVID-19 vaccines. Univariate analyses demonstrated that age (OR = 1.061; p = 0.017), diabetes mellitus (OR = 14.00; p = 0.002), anticoagulation (OR = 0.098; p = 0.004), and bowel resection (OR = 16.00; p = 0.001) were significantly associated with death in SVT patients with COVID-19; and anticoagulation (OR = 0.025; p = 0.003) and intravenous immunoglobulin (OR = 0.175; p = 0.046) were significantly associated with death in SVT patients who received COVID-19 vaccines. Multivariate analyses did not identify any independent factor for death in both patients. SVT in COVID-19 patients and in subjects who received COVID-19 vaccines carries a high mortality, but may be improved by anticoagulation. PROSPERO Identifier CRD42022315254.