Is there a decreased risk of intracerebral hemorrhage and mortality in obese patients treated with intravenous thrombolysis in acute ischemic stroke?

Background: The current guidelines do not recommend increasing the dose of intravenous recombinant tissue plasminogen activator (IV rt-PA) for ischemic stroke patients weighing >100 kg. Obese patients are therefore receiving an IV rt-PA dose <0.9 mg/kg; however, the consequences of such underdosing are unknown. Our goal was to determine the relationship between obesity and clinical outcomes among acute ischemic stroke patients receiving IV rt-PA. Methods: Data from all patients admitted to US hospitals between 2002 and 2009 who were treated with IV thrombolysis and who had a primary discharge diagnosis of stroke were included. The effect of obesity on rates of intracerebral hemorrhage and discharge outcomes was analyzed after adjusting for potential confounders using logistic regression analysis. Results: Of the 81,579 patients with ischemic stroke treated with IV rt-PA, 5174 (6.3%) were categorized as obese. The intracerebral hemorrhage rates in obese and nonobese patients were significantly different (4.5% v 6.3%; P = .01). After adjusting for age, sex, presence of hypertension, diabetes mellitus, location/teaching status and All Patient Refined Diagnosis Related Group severity scale, there was no difference in the rates of no to minimal disability between obese and nonobese patients (odds ratio [OR] 1.0; 95% confidence interval [CI] 0.8-1.2; P =.8). Obese patients had lower odds of in-hospital mortality (OR 0.6; 95% CI 0.5-0.8; P =.001) but also more likely to be discharged with moderate to severe disability (OR 1.2; 95% CI 1.01-1.3; P =.03). Conclusions: Obese patients receiving IV rt-PA treatment for acute ischemic stroke appear to have a higher survival rate most likely related to their decreased rates of intracerebral hemorrhage.