Reduced Physical Activity Levels in Children after Acute Venous Thromboembolism

INTRODUCTION: Venous thromboembolism (VTE), accompanied by its chronic sequelae such as post-thrombotic syndrome, has reached epidemic proportions. Early identification may offer an opportunity for effective intervention and reduction of long-term morbidity. Currently, no data is available regarding physical activity post-VTE in children and its relation to adverse post-VTE sequelae over time. Therefore, we sought to: (1) assess self-reported physical activity levels in children 6 months post-VTE and change over time from acute diagnosis, (2) compare activity levels of patients with and without adverse post-VTE sequelae, and (3) determine predictors of activity limitations after VTE and assess its association with health related quality of life (HRQoL). METHODS: Data on 50 children ages 2-21 years were extracted from our ongoing TOP study, with 36 diagnosed with lower extremity DVT and PE. We assessed pre-, 3, and 6 months post-VTE physical activity, using the Godin activity questionnaire. Age, race, ethnicity, gender, BMI, site of VTE, clot burden at diagnosis and follow-up, coagulation activation, dyspnea score, 6-minute walk distance (6MWD), and HRQoL were measured during follow-up. RESULTS: Out of 36 subjects, 20 had DVT, 16 had PE, and 3 had both DVT and PE. Of those followed for 12 months, 65% were active at 6 months post-diagnosis compared to 80% before. 36% of subjects had evidence of post-thrombotic sequelae ﾖ a composite of post-thrombotic syndrome per the Manco-Johnson Instrument and post-PE impairment at 12 months post-diagnosis. In multivariate analysis, age, race, ethnicity, gender, BMI, site of VTE, baseline or residual clot burden, and type of anticoagulant were not predictive of activity limitations at 6 months post-VTE. Decreased activity level at 6 months was not associated with a decreased HRQoL at this time. Insufficient activity compared with high activity, reduced 6MWD at 6 months, and coagulation activation (defined by D-dimer > 500 ng/mL at 3 months post-diagnosis) were predictive of increased short-term risk for post-thrombotic sequelae when assessed at 12 months post-diagnosis (OR 1.55, p <0.001; OR 2.7, p=0.02; OR 4.2, p=0.02 respectively). CONCLUSION: 35% of children with DVT and PE had activity limitations post-VTE that adversely influenced short-term post-VTE sequelae. Only 65% of children had resumed their usual activity within 6 months after VTE, highlighting this as a critical time period for interventions aimed at preventing post-VTE disease. Continual data accrual from our ongoing, prospective study may offer further insight to predict risk factors for decreased activity levels and walking distance in children after VTE.