Treatment differences and outcomes among myocardial infarction patients without standard modifiable risk factors: Data from CALLINICUS-Hellas Registry

Background It is increasingly recognized that patients might suffer from acute coronary syndrome (ACS) in the absence of standard modifiable risk factors (SMuRFs). Their treatment remains empirical. Purpose We examined the impact of SMuRF-less status on in-hospital management and long term outcomes. Methods CALLINICUS-Hellas Registry is an observational prospective study evaluating the adherence to lipid-lowering therapy among ACS patients. Two groups were created according to SMuRF status. The presence of diabetes mellitus, hypercholesterolaemia, hypertension or smoking history (either previously known or newly detected) was necessary to include the patient in the SMuRF group, while when all of them were absent; patients were classified as SMuRF-less. The patients were followed for 12 months after hospital discharge and the study’s endpoints were myocardial reinfarction or/and cardiac death. Results A total of 2718 consecutive patients with ACS were included and 68 cases (2.5%) were SMuRF-less. LDL-cholesterol [90 (74-104) mg/dl vs 114 (83-144) mg/dl , p<0.001], triglycerides [114 (83-144) mg/dl vs 124 (91-169) mg/dl , p=0.02] and waist circumference [97 (90-105) cm vs 101 (93-110) cm, p=0.03] were higher among patients with SMuRFs. SMuRF-less patients were more likely to have one vessel (63% vs 49%, p=0.01) or non-obstructive coronary artery disease (13% vs 4%, p=0.001) and less likely to receive reperfusion (78% vs 88%, p=0.01) or dual antiplatelet therapy (88% vs 96%, p=0.006). B-blockers and ACEi/ARB were equally prescribed between groups, yet patients with SMuRFs were more likely to receive ezetimibe combined with high intensity statins at discharge (31% vs 58%, p<0.001). SMuRF-less patients were more likely to attain lower LDL-cholesterol levels after 12 months of follow up [48 (36-61) mg/dl vs 57 (45-71) mg/dl, p=0.01) and to achieve values below 55 mg/dl (64% vs 45%, p=0.006). Nevertheless, myocardial reinfarction (4/68 vs 76/2650, Log Rank test p=0.223) and cardiac death rates (0/68 vs 47/2650, Log Rank test p=0.352) did not differ between groups. Conclusions SMuRF-less status is associated with treatment inequalities among contemporary ACS patients and the absence of SMuRFs does not dictate benign prognosis.