Acute hyperglycaemia is an adverse prognostic factor in patients with acute coronary syndrome (ACS). It is unclear whether these negative effects apply equally to patients with diabetes mellitus (DM) and non-DM patients.
To evaluate the short-term (in-hospital) and long-term (four-year) prognostic value of acute hyperglycaemia in ACS patients with or without DM.
The study involved 116 ACS patients admitted between 2004 and 2006 to our department, who were selected for invasive treatment and who had both admission and first fasting glucose levels measured. Patients were classified as DM (n = 23), on the basis of a known history of diabetes or newly detected diabetes, or non-DM (n = 93). Acute hyperglycaemia was defined as an admission glycaemia ≥ 10.0 mmol/L (180 mg/dL) for non-DM patients, or ≥ 7.8 mmol/L (140 mg/dL) for DM patients, or a first fasting glucose level ≥ 5.6 mmol/L (100 mg/dL) for both DM and non-DM patients. The primary end-point was defined as mortality during follow-up. The secondary end-points were death, cardiac arrest or repeated ACS occurrence, stroke or transient ischaemic attack, and the need for repeat percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) procedure during the in-hospital and four-year post-hospital periods. During follow-up, patients were assessed for a composite end-point defined as all-cause death, repeated ACS occurrence, repeat PCI or CABG procedure, and stroke.
Acute hyperglycaemia was present in 28 non-DM and 14 DM patients. The mean follow-up time was 4 ± 0.6 years. For DM patients, there was no significant difference in four-year mortality between hyperglycaemic and normoglycaemic patients (14.3% vs 11.1%, respectively; NS). The occurrence of secondary end-points and composite end-point frequency was also similar for these subgroups, both for in-hospital and four-year observations. For non-DM patients, the four-year mortality was similar for hyperglycaemic and normoglycaemic subjects (17.9% vs 10.8%, respectively; NS), whereas cardiac arrest during the in-hospital period was more common for hyperglycaemic than normoglycaemic patients (3.6% vs 0.0%, respectively; n = 1 vs 0; p = 0.01). The composite end-point for the in-hospital period was reached by 17.6% of hyperglycaemic and 13.8% of normoglycaemic non-DM patients (NS). The composite end-point during the four-year observation period was more frequently reached in hyperglycaemic than in normoglycaemic non-DM patients (78.6% vs 56.9%, respectively; p = 0.04).
Acute hyperglycaemia in non-DM patients hospitalised due to ACS was found to be an unfavourable long-term (four-year) risk factor, and may also be an unfavourable in-hospital risk factor. In contrast, acute hyperglycaemia did not affect cardiovascular outcomes in DM patients.