Serum cholesterol levels and survival after rtPA treatment in acute stroke

According to the reverse epidemiology hypothesis, high cholesterol levels might be protective and associated with greater survival rates under certain conditions. In stroke patients, a clear correlation between lipid levels and mortality after ischaemic and hemorrhagic strokes has been demonstrated. The aim of this study was to analyze the impact of lipid levels on 3-month mortality in patients with ischaemic stroke (IS) homogeneously treated with intravenous rtPA and admitted to a monitored acute stroke unit.

Retrospective analysis of a prospective cohort of 220 patients with an IS treated with rtPA within the first 4.5 h in a single tertiary hospital from January 2005 to August 2010.

Mortality at 3 months was 15.0%. Univariate analysis showed that age, NIHSS at admission, heart failure, and atrial fibrillation were directly related to 3-month mortality; cholesterol, triglycerides, and low density lipoprotein were inversely associated. The death rate by cholesterol level was 5.5% for the highest tertile (>192 mg/dl), 13.7% for the middle (192-155 mg/dl), and 25.7% for the lowest (<155 mg/dl), P = 0.003. Multivariate analysis showed that amongst the lipid determinations, only cholesterol [OR: 0.985 (95% CI: 0.972-0.998), P = 0.021] was inversely associated with 3-month mortality. The 'protective' effect of cholesterol was independent of stroke severity and remained significant in non-lacunar strokes.

Survival of stroke patients receiving current, most effective medical treatment is related to blood cholesterol levels, with an inverse relationship between cholesterol and mortality. The mechanism of this apparently paradoxical situation remains unexplained but merits further research.