# Prevalence of venous thromboembolism and associated factors in COVID-19 patients at a provincial public hospital in southern Brazil

## TL;DR

This study finds that intubation and excess weight increase the risk of blood clots in hospitalized COVID-19 patients, while anticoagulant use is protective.

## Contribution

The study identifies specific risk and protective factors for venous thromboembolism in a hospitalized COVID-19 population in Brazil.

## Key findings

- Intubation increases the risk of venous thromboembolism (OR 2.3).
- Excess weight is a significant risk factor for VTE (OR 3.3).
- Prophylactic anticoagulation acts as a protective factor (OR 0.02).

## Abstract

COVID-19 is a predominantly respiratory disease, but it also has a strong association with thromboembolism, especially among hospitalized patients.

To evaluate the prevalence of venous thromboembolism (VTE) and associated factors in patients with COVID-19 in a public hospital in the interior of South Brazil.

A retrospective, cross-sectional observational study was carried out by analyzing data from medical records. The VTE outcome was a composite of acute pulmonary thromboembolism (PTE) and deep vein thrombosis (DVT). Associations were analyzed by logistic regression and bivariate analyses using Pearson’s chi-square test.

The sample comprised 964 patients. 56% were male and 44% female, with a mean age of 58.2 ± 15.1 years. 70% of patients were admitted to the ICU, 44.4% died, 97% required oxygen, and 63.7% required intubation. After adjusted analysis, the factors intubation (p=0.02) and prophylactic anticoagulation (p<0.001) were associated with VTE. The following variables were shown to be important risk factors for VTE: intubation (OR 2.3; 95% CI 1.1-4.8, p=0.020) and excess weight (OR 3.3; 95% CI 0.2-2.2, p=0.02), while prophylactic anticoagulation showed a small protective factor (OR 0.02; 95% CI 0.01-0.04, p<0.001).

The results demonstrate how COVID-19, together with several other associated factors, especially intubation, excess weight, and use of anticoagulants, may be related to thromboembolism as risk factors and protective factors. Prophylactic anticoagulation, in particular, was a protective factor.

A covid-19 é uma doença predominantemente respiratória, embora tenha forte associação com o tromboembolismo, principalmente entre pacientes hospitalizados.

Avaliar a prevalência de tromboembolismo venoso (TEV) e os fatores associados em pacientes com covid-19 em um hospital público do interior no Sul do Brasil.

Estudo transversal realizado por meio de uma análise dos dados documentados em prontuários. O desfecho TEV foi constituído a partir do tromboembolismo pulmonar agudo e da trombose venosa profunda. As associações foram analisadas por regressão logística e a análise bivariada foi realizada pelo teste do qui-quadrado de Pearson.

A amostra contou com 964 pacientes, sendo 56% do sexo masculino e 44% do feminino, com idade média de 58,2±15,1 anos. No total, 70% dos pacientes foram admitidos em unidade de terapia intensiva, 44,4% evoluíram para óbito, 97% necessitaram de oxigênio e 63,7% de intubação. Após análise ajustada, estiveram associados ao TEV os fatores intubação (p = 0,02) e anticoagulação profilática (p < 0,001). Demonstraram ser fatores de risco importantes para TEV as variáveis intubação (odds ratio [OR] 2,3; IC95% 1,1-4,8; p = 0,020) e excesso de peso (OR 3,3; IC95% 0,2-2,2; p = 0,02), enquanto a anticoagulação profilática mostrou-se como pequeno fator protetor (OR 0,02; IC95% 0,01-0,04; p < 0,001).

Os resultados encontrados demonstraram o quanto a covid-19, em conjunto com diversos outros fatores associados, destacando-se a intubação, excesso de peso e uso de anticoagulantes, pode estar relacionada ao tromboembolismo, tanto como fator de risco quanto de proteção. A anticoagulação profilática, em especial, mostrou-se como fator protetor para o TEV.