Abstract 201: Effect of Statin Treatment Before and After Hospitalization on Mortality Following Acute Ischemic Stroke: Importance of Confounding by Stroke Severity and Palliative Care
Background: Statins may improve outcomes following acute ischemic stroke (AIS), but studies often fail to account for confounders such as stroke severity and palliative care. We examined the effect of statin treatment both before and after hospital admission in AIS.
Methods: Data were prospectively collected from 10646 AIS admissions to 11 hospitals participating in the Registry of the Canadian Stroke Network between 2003-2008. The effect of statins taken before and after admission on stroke mortality was determined using multivariable logistic regression. We repeated analyses using oral hypoglycemic agents as a marker of the avoidance of oral agents in the acute setting.
Results: Pre-admission 31% of patients were taking statins. Severe stroke (Canadian Neurological Scale < 5) was slightly lower in patients using statins pre-admission (19.2% vs. 20.9%). Pre-admission statins were associated with significantly lower adjusted mortality at 180-days (OR=0.82, 95% CI 0.69, 0.97), but not at 30-days (OR=0.90, 95% CI 0.73, 1.11). Post-admission 65% of patients received statins. Patients who were on statins pre-admission but off statins post-admission (i.e., ‘On-Off’ or discontinuation) had strikingly higher mortality, however, this effect was markedly attenuated after adjustment (Table). Stroke severity and palliative care were identified as major confounders. Continuing or initiating statin treatment post-admission was associated with significantly lower mortality compared to patients who were never treated with statins, however, oral hypoglycemic agents exhibited similar associations (Table).
Conclusions: Pre-admission statin use was associated with lower 6-month mortality. Stroke severity and palliative care confounded the relationships between post-admission treatment and mortality, especially for patients in whom statins were discontinued. Well conducted RCTs are needed to quantify the benefits of statins in the acute setting.
- © 2012 by American Heart Association, Inc.