OBJECTIVES: This study compared the effectiveness of rosuvastatin (RSV) to other statins prescribed in clinical practice in prevention of fatal and non-fatal cardiovascular (CV) events. METHODS: This longitudinal inception cohort study, conducted using MedStat MarketScan research databases, included patients aged =18 who started statin therapy during August 2003 to December 2005. Patients were followed until 90 days after index statin monotherapy exposure, an event, end of eligibility, or end of study. The primary endpoint was a composite of CV death (in-hospital only), myocardial infarction, unstable angina, coronary revascularization, stroke, and carotid revascularization. Adjusted time-to-event analyses incorporating a propensity score covariate were used, and analyses were stratified by duration of statin exposure. RESULTS: Among 395,039 patients who met inclusion/exclusion criteria, 12% initiated rosuvastatin (RSV), and 9,622 (2.4%) experienced an outcome event (3.7 per 100 person-years). The median (mean) duration of statin treatment and follow-up was 100 (180) days and 180 (242) days, respectively. Although no statistically significant difference in CV event rates between RSV and other statins was observed after adjustment for demographics and medical/prescription history (HR=0.99, 95% CI=0.93-1.06), a trend toward increased benefit was seen with longer exposure time with RSV compared to "other statins" (³90 days exposure, HR=0.97, 95% CI=0.86-1.09; ³180 days, HR=0.91, 95% CI=0.78-1.06; ³270 days, HR=0.80, 95% CI=0.64-1.00; ³360 days, HR =0.88, 95% CI=0.65-1.19). Other study end-points, stratifications, and comparisons with specific statin drugs were evaluated. CONCLUSION: Primary analysis showed similar incidence rates of CV-related events in a clinical practice setting between the statin cohorts over a median of 180 days of follow-up. With longer exposure times, a trend of a decreased CV event rate with RSV as compared to other statins was found. These findings are consistent with a beneficial effect of aggressive LDL lowering treatment in a clinical practice setting.