Nasopharyngeal viral load at admission is not an independent predictor of thromboembolic complications in unvaccinated COVID-19 hospitalized patients.

Abstract

COVID-19 patients may develop thrombotic complications, and data regarding an association between nasopharyngeal viral load and thrombosis is scarce. The aim of our study was to evaluate whether SARS-CoV-2 nasopharyngeal viral load upon admission is a useful prognostic marker for the development of thromboembolic events in patients hospitalized for SARS-CoV-2 infection. We performed a retrospective study of all hospitalized patients with a positive PCR test for SARS-CoV2 who had deep vein thrombosis (DVT), pulmonary embolization (PE), or arterial thrombosis diagnosed during their clinical course in a single academic center. The study population was divided according to the cycle threshold (Ct) value upon admission in patients with high viral load (Ct < 25), intermediate/medium viral load (Ct 25-30), and low viral load (Ct > 30). A regression model for propensity was performed matching in a 1:3 ratio those patients who had a thrombotic complication to those who did not. Among 2,000 hospitalized COVID-19 patients, 41 (2.0%) developed thrombotic complications. Of these, 21 (51.2%) were diagnosed with PE, eight (19.5%) were diagnosed with DVT, and 12 (29.2%) were diagnosed with arterial thrombosis. Thrombotic complications occurred as frequently among the nasopharyngeal viral load or severity stratification groups with no statistically significant differences. Univariate logistic regression revealed increased odds for thrombosis only in mechanically ventilated patients OR 3.10 [1.37, 7.03] (p = 0.007). Admission SARS-CoV-2 nasopharyngeal viral loads, as determined by Ct values, were not independently associated with thromboembolic complications among hospitalized patients with COVID-19.