Russell Mitesh Cerejo, MD
Chaturvedi S, Turan TN, Lynn MJ, Derdeyn CP, Fiorella D, Janis LS, et al. Do Patient Characteristics Explain the Differences in Outcome Between Medically Treated Patients in SAMMPRIS and WASID? Stroke. 2015
Dr. Chaturvedi and colleagues have put to rest the question of whether patient characteristics in the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) and Warfarin Aspirin Symptomatic Intracranial Disease (WASID) trials differed given the low incidence of primary outcomes in the SAMMPRIS group.
In their paper, “Do patient characteristics explain the differences in outcome between medically treated patients in SAMMPRIS and WASID?” they compared patients from WASID trial with identical inclusion criteria as that of SAMMPRIS to establish that it was truly aggressive medical therapy that was responsible for the lower incidence rated of primary outcomes. The 1, 2 and 3-year rates of the primary endpoint were 42%, 41% and 48% lower respectively in SAMMPRIS medically-treated patients compared with WASID patients who met the SAMMPRIS inclusion criteria. This was despite the fact that patients enrolled in SAMMPRIS had higher percentage of hypertension, severe stenosis, elevated body mass index and higher rate of old infarcts in the symptomatic artery territory. SAMMPRIS patients had a better lipid profile, likely related to the statin therapy in the trial. The baseline characteristics that were both different between the studies and related to outcome and thus potential confounders were no statin use at enrollment (more prevalent among WASID patients) and old infarcts in the territory of the symptomatic artery (more prevalent among SAMMPRIS patients). After adjusting for this, the estimated hazard ratio for WASID vs SAMMPRIS was 1.9 (95% CI = 1.1 – 3.2, p = 0.016) demonstrating a higher risk of the outcome among WASID patients. This study elucidates the likely reason for improved outcomes seen in the medical arm of SAMMPRIS compared to the predicted rates based on the WASID trial.