PURPOSE:An increased incidence of subclinical hypothyroidism has been shown in patients with unprovoked deep venous thrombosis. Moreover, there is evidence that subclinical hypothyroidism may be associated with a hypercoagulable state. The purpose of this investigation is to test the hypothesis that hypothyroidism may be a risk factor for venous thromboembolism (VTE).
METHODS:The number of patients discharged from hospitals with an ICD-9-CM code of hypothyroidism from 1979 through 2005 was obtained from the National Hospital Discharge Survey (NHDS). Among these patients the number with pulmonary embolism (PE) and with deep venous thrombosis (DVT) was determined. The NHDS consists of data obtained annually from approximately 270,000 sampled inpatient records from about 500 non-Federal short-stay hospitals (average length of stay <30 days) in 50 states and the District of Columbia. Population estimates were from the United States Bureau of the Census.
RESULTS:Among 19,519,000 hospitalized patients discharged with a diagnose of hypothyroidism from 1979 to 2005, 0.61% had PE, while in patients with no thyroid dysfunction, PE was diagnosed in 0.37% of 908,805,000 patients (relative risk of 1.64, 95% CI 1.63–1.65). Deep venous thrombosis was diagnosed in 1.36% of hypothyroid patients and in 0.84% of patients with no thyroid dysfunction (relative risk of 1.62, 95% CI 1.61–1.62).The relative risk for PE in patients with hypothyroidism was highest in patients <40 years of age (relative risk 3.99). In patients aged 40- 59 years, the relative risk for PE was 1.46. In older patients, the relative risk for PE was lower. Similarly, the relative risk for DVT was highest in patients <40 years (2.25), lower in patients aged 40- 59 years (1.17) and somewhat lower in patients > 60 years (1.11). Hypothyroid females had a greater risk for PE and DVT than hypothyroid males (relative risk 1.42 and 1.16 respectively).
CONCLUSION:Hospitalized patients with hypothyroidism have a greater risk for PE and DVT than patients without thyroid dysfunction.
CLINICAL IMPLICATIONS:Hospitalized patients with hypothyroidism may be candidates for antithrombotic prophylaxis.
DISCLOSURE:Liviu Danescu, No Financial Disclosure Information; No Product/Research Disclosure Information