RISK FACTORS FOR THE DEVELOPMENT OF HOSPITAL-ACQUIRED PEDIATRIC VENOUS THROMBOEMBOLISM: DEALING WITH POTENTIALLY CAUSAL AND CONFOUNDING RISK FACTORS USING DIRECTED ACYCLIC GRAPH (DAG) ANALYSIS [article]

Leonardo Campos, Mauricio Petroli, Flavio Roberto Sztajnbok, Elaine Sobral Costa, Leonardo Rodrigues Brandao, Marcelo Gerardin Poirot Land
2020 medRxiv   pre-print
Hospital-acquired venous thromboembolism (HA-VTE) in children comprises multiple risk factors that should not be evaluated separately due to collinearity and multiple cause and effect relationships. This is one of the first case-control study of pediatric HA-VTE risk factors using Directed Acyclic Graph (DAG) analysis (figure 1). Material and Methods: Retrospective, case-control study with 22 cases of objectively confirmed HA-VTE and 76 controls matched by age, sex, unit of admission, and
more » ... of hospitalization. Descriptive statistics was used to define distributions of continuous variables, frequencies, and proportions of categorical variables, with a comparison between cases and controls. Due to many potential risk factors of HA-VTE, a directed acyclic graph (DAG) model was created to identify confounding, reduce bias, and increase precision on the analysis. The final model consisted of a DAG-based conditional logistic regression. The study was approved by the Institutional Review Board (CAAE 58056516.0.0000.5264). Results: In the initial univariable model, the following variables were selected as potential risk factors for HA-VTE: length of stay (LOS, days), immobility, ICU admission in the last 30 days, LOS in ICU, infection, central venous catheter (CVC), number of CVCs placed, L-asparaginase, heart failure, liver failure, and nephrotic syndrome. The final model (Table 1) revealed LOS (OR=1.106, 95%CI=1.021-1.198, p=0.013), L-asparaginase (OR=26.463, 95%CI=1.609-435.342, p=0.022), and nephrotic syndrome (OR=29.127, 95%CI=1.044-812.508, p=0.004) as independent risk factors for HA-VTE. Conclusion: The DAG-based approach was useful to clarify the influence of confounders and multiple causalities of HA-VTE. Interestingly, CVC placement - a known thrombotic risk factor highlighted in several studies - was considered a confounder, while liver failure, LOS, L-asparaginase use, and nephrotic syndrome were confirmed as risk factors to HA-VTE. Large confidence intervals are related to the sample size, however, the results were significant. Keywords: thrombosis, pediatrics, risk assessment, risk factors, venous thromboembolism, Directed Acyclic Graph
doi:10.1101/2020.07.17.20153718 fatcat:fbgpyojarzhddgwfgosvyl2pii