Risk factors for venous thromboembolism in patients with nephrotic syndrome: a retrospective cohort study

Background. Nephrotic syndrome is associated with an increased risk of venous thromboembolism (VTE). However, the risk factors of VTE in nephrotic syndrome, other than hypoalbuminemia and severe proteinuria, are not well established. Therefore we aimed to investigate the risk factors of VTE in patients with nephrotic syndrome. Methods. This retrospective cohort study used data from a Japanese nationwide claims database. We identified patients >= 18 years of age hospitalized with nephrotic syndrome. Through multivariable logistic regression, we determined the risk factors of VTE in patients with nephrotic syndrome during hospitalization. Results. Of the 7473 hospitalized patients with nephrotic syndrome without VTE, 221 (3.0%) developed VTE. In the VTE group, 14 (6.3%), 11 (5.0%) and 198 (89.6%) patients developed pulmonary embolism, renal vein thrombosis and deep vein thrombosis, respectively. We found that female sex {odds ratio [OR] 1.39 [95% confidence interval (CI) 1.05-1.85]}, body mass index (BMI) >= 30 [OR 2.01 (95% CI 1.35-2.99)], acute kidney injury [AKI; OR 1.67 (95% CI 1.07-2.62)], sepsis [OR 2.85 (95% CI 1.37-5.93)], lupus nephritis [OR 3.64 (95% CI 1.58-8.37)] and intravenous corticosteroids use [OR 2.40 (95% CI 1.52-3.80)] were associated with a significantly higher risk of developing VTE. Conclusions. In patients with nephrotic syndrome, female sex, BMI >= 30, AKI, sepsis, lupus nephritis and intravenous corticosteroid use may help evaluate the risk of VTE.