Dehydration and venous thromboembolism after acute stroke

Background: Although it is widely assumed that dehydration predisposes to venous thromboembolism (VTE), there are no clinical studies to support this. Aim: To evaluate the relationship between biochemical indices of dehydration and VTE after acute ischaemic stroke (AIS). Design: Prospective observational study. Methods: Unselected AIS patients (n=102) receiving standard thromboprophylaxis with aspirin and graded compression stockings, underwent serial measurements of serum urea, creatinine and osmolality, and were screened for VTE using magnetic resonance direct thrombus imaging. Results: Serum osmolality of >297 mOsm/kg, urea >7.5 mmol/l and urea:creatinine ratio (mmol:mmol) >80 a few days post-AIS were associated with odds ratios for VTE of, respectively, 4.7, 2.8 and 3.4 (p = 0.02, 0.05, 0.02) on multivariable analysis. Discussion: Dehydration after AIS is strongly independently associated with VTE, reinforcing the importance of maintaining adequate hydration in these patients.