Predictors for the development of post-thrombotic syndrome in patients with primary lower limb deep venous thrombosis: A case–control study

Introduction: Post-thrombotic syndrome is a common and debilitating sequelae of lower limb deep venous thrombosis. Very little awareness is present about the risk factors and about the diagnosis, prevention, and treatment of this condition. Objective: The objective of this study is to identify the predictors of post-thrombotic syndrome after lower limb deep venous thrombosis. Materials and methods: A case–control study was conducted on all adult patients who were admitted with lower limb deep venous thrombosis at our institution from January 2005 to June 2012. These patients were scheduled for a research clinic visit, which included informed consent, data collection, and physical examination. Patients found to have post-thrombotic syndrome served as cases and those without post-thrombotic syndrome served as controls. Villalta scoring system was used to diagnose the post-thrombotic syndrome and then to assess the severity of the condition in both the groups. Cox regression risk factor analysis was performed to identify the predictors of post-thrombotic syndrome. Results: Out of the 125 patients examined, 49 were found to have post-thrombotic syndrome. Risk factors found to be significant were body mass index of more than 35 kg/m² (n = 13, p = 0.003), history of immobilization (n = 19, p = 0.003), one or more hypercoagable disorders (n = 32, p = 0.02), iliofemoral deep venous thrombosis (n = 18, p = 0.001), complete obstruction on ultrasound (n = 26, p = 0.016), unstable range of international normalized ratio (n = 23, p = 0.041) and non-compliance for the use of compressions stockings (n = 14, p = 0.001). On multivariate analysis, one or more hypercoagable disorder, iliofemoral deep venous thrombosis, and non-compliance to the use of compression stockings were found to be independent risk factors for the development of post-thrombotic syndrome. Conclusion: One or more hypercoagable disorders, iliofemoral deep venous thrombosis and non-compliance to the use of compression stockings were independent predictors of post-thrombotic syndrome after deep venous thrombosis. These findings will help prognosticate and prevent development of PTS in similar patient populations.