Background: Low-density lipoprotein cholesterol (LDL-C) is the independent risk factor for coronary artery disease. Diabetes mellitus (DM) is associated with poor outcome in patients with ST-segment elevation myocardial infarction (STEMI) treated with percutaneous coronary interventions (PCI). The relationship between LDL-C and mortality in patients with STEMI has not been well established.
Aim: To assess whether the LDL-C level on admission can predict in-hospital mortality in patients with or without DM treated with PCI for STEMI.
Methods: 1808 consecutive patients with STEMI (378 with DM) treated with PCI were included in the analysis. Patients were divided according to the presence of DM and LDL-C level on admission with a threshold of 3.7 mmol/L (143 mg/dL). In the diabetic group there were 208 patients with LDL-C〈 3.7 mmol/L (143 mg/dL) and 170 with LDL-C ≥ 3.7 mmol/L (143 mg/dL), whereas in the non-diabetic group 726 and 704 patients, respectively. We analysed the effects of LDL-C level and various risk factors on in-hospital mortality separately for patients with or without DM.
Results: The mean total cholesterol (5.6 ± 1.4 vs 5.7 ± 1.5 mmol/L; 216.6 ± 54.1 vs 220.4 ± 58 mg/dL, p = 0.21), LDL-C (3.6 ± 1.3 vs 3.7 ± 1.5 mmol/L; 139.2 ± 50.3 vs 143.0 ± 58 mg/dL, p = 0.11) and triglyceride level (1.7 ± 0.6 vs 1.6 ± 0.5 mmol/L; 150 ± 52.9 vs 141.2 ± 44.1 mg/dL, p = 0.30) were similar in patients with or without DM, whereas HDL-C level was lower in diabetic patients (1.4 ± 0.6 vs 1.8 ± 0.5 mmol/L; 53.7 ± 23.0 vs 69 ± 19.2 mg/dL, p = 0.049). The in-hospital mortality was 6.1% and 3.2%, for patients with or without DM, respectively (p = 0.008). In the diabetic group in-hospital mortality was higher in patients with LDL-C level on admission ≥ 3.7 mmol/L (143 mg/dL) in comparison to the patients with LDL-C〈 3.7 mmol/L (143 mg/dL; 7.1% vs 4.8%; p = 0.03). The multivariate analysis revealed that in diabetics an increase in LDL-C level on admission by 1 mmol/L (38.67 mg/dL) was related to a 45% increase in in-hospital mortality (OR 1.45, 95% CI 1.10-2.00, p = 0.023). In the non-diabetic group in-hospital mortality was similar in patients with LDL-C level on admission ≥ 3.7 mmol/L (143 mg/dL) and〈 3.7 mmol/L (143 mg/dL); 2.6% vs 3.7%; p = 0.21. In multivariate analysis LDL-C level was not related with in-hospital mortality in patients without DM (per 1 mmol/L; 38.67 mg/dL); OR 0.95, 95% CI 0.70-1.27, p = 0.71.
Conclusions: Elevated LDL-C level on admission is associated with increased in-hospital mortality in diabetic but not in non-diabetic patients treated with PCI for STEMI.