Relationship between low-density lipoprotein cholesterol level on admission and in-hospital mortality in patients with ST-segment elevation myocardial infarction, with or without diabetes, treated with percutaneous coronary intervention.

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.