Background: Previous trials have found that low low-density lipoprotein-cholesterol (LDL-C) on admission was associated with increased mortality in patients with acute myocardial infarction (AMI). There are few reports, however, on the effect of low LDL-C with or without in-hospital statin treatment on short-term prognosis in AMI patients.
Methods and results: A total of 9,032 AMI patients underwent primary PCI in 68 centers in the Tokyo CCU Network Registry during 2009-2012, in whom LDL-C was measured in 6,486. We divided them into 4 groups: statin-treated/LDL-C <100 mg/dl (n=1,236), statin-treated/LDL-C ≥ 100 mg/dl (n=3,671), statin-naïve/LDL-C <100 mg/dl (n=662), and statin-naïve/LDL-C ≥ 100 mg/dl (n=917). We assessed hospital mortality within 30 days. In-hospital all-cause mortality was significantly lower in the statin-treated/LDL-C ≥ 100-mg/dl group (3.2%, P<0.001). On multivariate Cox regression analysis, adjusted for age, gender, hypertension, diabetes mellitus, dyslipidemia and other clinical factors, the combination of statin treatment and LDL-C ≥ 100 mg/dl was an independent predictor of lower in-hospital mortality (adjusted HR, 0.211; 95% CI: 0.096-0.462; P<0.001). In the LDL-C <100-mg/dl patients, statin treatment also independently reduced in-hospital mortality (adjusted HR, 0.467; 95% CI: 0.223-0.976; P=0.043). Spontaneously low LDL-C was associated with increased short-term mortality.
Conclusions: Statin treatment was associated with better short-term outcome in patients with AMI, even in patients with low LDL-C.