Clinical Implication of TSH Screening in Venous Thromboembolism Patients

Background: Venous thromboembolism (VTE) that have significant morbidity and mortality for patients in the community and hospital. A recent meta-analysis found a significantly increased risk of incidence VTE among patients with hyperthyroidism compared to patients without hyperthyroidism. To our knowledge, no study has attempted to explore whether screening for TSH levels in VTE patients leads to a diagnosis of undiagnosed thyroid dysfunction as VTE could be the first presenting symptom. Method: We conducted a retrospective cohort study and analyzed data of all patients treated at University Medical Center, Lubbock, Texas in 18-85 years of age with a diagnosis of DVT and/or PE in 2019. Qualitative chart review to identify cases of clinically significant TSH screening in VTE patients that leads to thyroid dysfunction diagnosis. Associations between variables tested using Student’s t-test, chi-square, and Fisher’s exact test. Results: Of total of 533 participants with diagnosis of VTE in 2019, 85 participants were included in the study. Seven participants (8.24%) were found to have high TSH level (>4.2 mIU/mL). None of them was found to have low level of TSH. Participants in high TSH group were more likely to be female (71.43%) and Caucasian (71.43%). In high TSH group patients tended to have both PE and DVT diagnosis at the same admission (71.43%). Weight and BMI were significance higher than those with normal TSH level. Segna et al conducted a prospective multicenter cohort study on association between thyroid dysfunction and venous thromboembolism. The study measure thyroid hormones and thrombophilic biomarkers at 1 year after the acute VTE and follow for the recurrent VTE (rVTE). They found that after 20.8 months of follow-up, 9% developed rVTE. However, none of them was found in subclinical hyperthyroidism group. Furthermore, in their multi-variate analyses, the hazard ratio for rVTE was 0.80 (95%CI 0.23-2.81) subclinical hyperthyroidism compared with euthyroid participants. They concluded that subclinical hyperthyroidism may be associated with lower rVTE risks. Similarly, with Liviu study found hyperthyroidism was not associated with an increased risk of VTE. Qualitative chart review in our patients with high TSH resulted that none of them had history of tobacco use. One participant was on birth control pills with the history of cervical carcinoma. Conclusion:The association of thyroid dysfunction and the development of VTE is debated on the literature review. In our study we found multiple patients with high TSH level (8.24%) in VTE patients with no prior history of thyroid dysfunction. TSH could play an important role in hypercoagulable state. Subclinical hypothyroidism and/or hypothyroidism may induce a prothrombotic event. However, larger cohort studies with higher prevalence of high TSH participants are needed to prove a relationship between TSH level and VTE events.