Real world prognostic impact and predictors of adherence to statin therapy after STEMI on first year follow up: results from the FAST STEMI registry

Background The impact of statin therapy on cardiovascular outcomes after ST-elevation acute myocardial infarction (STEMI) in real-world patients is understudied. Purpose The aim of this study was to identify predictors of low compliance to statin therapy and estimate its impact on cardiovascular (CV) outcomes and mortality in the first year after the index event. Methods We evaluated real-world adherence to the most common cardiovascular drugs by comparing the number of bought tablets in drugstores to the expected tablets at 1 year and on total follow-up length. A total amount of 6043 patients from 2012 to 2017 was enrolled in the FAST STEMI registry and followed up for 4,7±1,6 years; 299 patients with intraprocedural and intrahospital deaths were excluded. The main outcomes evaluated were all-cause death, cardiovascular death, myocardial infarction, major and minor bleeding events and ischemic stroke. The best compliance cut-off was found by ROC curve analysis with Youden index; Kaplan Meier and Cox proportional hazard models were performed to evaluate cumulative event rates of cardiovascular mortality at follow-up. Predictors of lower adherence were evaluated at univariate and multivariate analysis with logistic regression. Results From a total of 5744 patients 4333 were men (75,4%) with an average age of 64,7±12,5 years old; 699 (2,2%) were diabetic, 311 (5,4%) presented with severe chronic kidney disease (CKD) while 237 (4,1%) had previous ischemic cardiopathy disease. Mean statin adherence was 89,9% (IQR 41,1 – 100): after univariate and multivariate analysis age≥75 (OR 0.597, IC 0.514-0.692), previous ischemic stroke (OR 0.607, IC 0.416-0.886), known ischemic cardiopathy (OR 0.675, IC 0.503-0.904) and chronic kidney disease (OR 0.667, IC 0.552-0.879) resulted as predictors of lower compliance, whereas preserved ejection fraction (OR 1.282, IC 1.133-1.457) resulted predictor of adequate adherence to statin therapy. Statin adherence upper than 49.05% (identified at Youden’s analysis as best cut-off) reduced both cardiovascular (0,3% vs. 6,8%; HR 0.33; 95%CI 0.18-0.59; p = 0,001) and all-cause mortality (0,7% vs 18,1%, HR 0,22, 95%CI 0.15-0.37, p<0.001). Regarding cardiovascular outcomes, statin optimal adherence reduced ischemic stroke incidence (1% vs 2,5%, p=0.001) while there was no difference on the number of myocardial infarctions nor hemorrhagic events at 1-year follow up. Conclusions In the real-world setting, statin adherence after STEMI was independently associated to a reduction of cardiovascular mortality, all-cause mortality and ischemic stroke incidence at 1-year follow-up. Elderly age, previous ischemic stroke, known ischemic cardiopathy and CKD resulted as independent predictors of lower compliance to statin therapy.