Risk Factors and Prediction Model Construction of Post-thrombotic Syndrome in Patients with Deep Vein Thrombosis of Lower Extremities

WANG Lei; LIU Cheng

doi:10.12102/j.issn.1672-1349.2025.13.012

Abstract：Objective: To explore the risk factors for post-thrombotic syndrome (PTS) in patients with lower extremity deep vein thrombosis (DVT) and to construct a prediction model. Methods: A total of 374 DVT patients hospitalized at Weifang Medical University Affiliated Hospital from January 2020 to March 2023 were selected as the study subjects. Patients with Villata scores of 0-4 were classified into the non-PTS group, while those with scores of 5-33 were classified into the PTS group. Demographic characteristics, comorbidities, surgical information, and laboratory indicators were collected. Multivariate logistic regression analysis was used to screen independent risk factors for PTS. The R software was used to build a risk prediction model for PTS. Calibration curves were used for internal validation of the prediction model, and decision curves were used to evaluate the predictive performance of the model. Results: Among the 374 DVT patients, 64 (17.11%) developed PTS. Of these, 310 (82.89%) had no PTS, 28 (7.49%) had mild PTS, 20 (5.35%) had moderate PTS, and 16 (4.28%) had severe PTS. Univariate analysis showed statistically significant differences between the non-PTS and PTS groups in terms of age > 60 years, body mass index (BMI) > 27 kg/m², varicose veins, iliac vein compression syndrome, DVT classification, surgery, and compression therapy (P < 0.05). Logistic regression analysis showed that age > 60 years, BMI > 27 kg/m², presence of varicose veins, iliac vein compression syndrome, DVT classification (mixed type), and surgery were risk factors for PTS in DVT patients, while compression therapy was a protective factor (P < 0.05). A prediction model was constructed, with scores ranked from highest to lowest as follows: presence of varicose veins (89.5 points), iliac vein compression syndrome (71.0 points), DVT classification (mixed type) (56.0 points), absence of compression therapy (39.0 points), surgery (32.5 points), age > 60 years (23.0 points), and BMI > 27 kg/m² (10.0 points). The PTS risk prediction model showed good fit (χ² = 3.254, P = 0.074), with an area under the receiver operating characteristic (ROC) curve of 0.753 [95% CI (0.715, 0.806)], sensitivity of 0.815, specificity of 0.637, and Youden index of 0.458. Conclusion: Varicose veins, iliac vein compression syndrome, DVT classification (mixed type), surgical treatment, absence of compression therapy, age > 60 years, and BMI > 27 kg/m² are risk factors for PTS in DVT patients. The risk prediction model constructed in this study has high sensitivity and specificity for predicting PTS after DVT, and can achieve risk prediction for PTS.