Admission glucose as a prognostic marker for all-cause mortality and cardiovascular disease.

BACKGROUND: Diabetes and prediabetes are known risk factors for cardiovascular disease and associated with increased mortality risk. Whether patients with a random elevated blood glucose level but no history of diabetes are at a higher mortality and cardiovascular risk is not entirely known. METHODS: A retrospective cohort study where patients (18-80 years) with no history of diabetes between 2006 and 2016 attending the emergency department (ED) in Sweden were included. Based on the first (index) blood glucose level patients were categorized into four groups: hypoglycemia (< 3.9 mmol/L), normal glucose tolerance (NGT) (3.9-7.8 mmol/L), dysglycemia (7.8-11.1 mmol/L), and hyperglycemia (> 11.1 mmol/L). Data was collected from four nationwide registers (National Patient Register, National Cause of Death Register, Prescribed Drug Register and Statistics Sweden). Cox regression was used to calculate adjusted hazard ratios (HR) with 95% confidence intervals (CI) for all-cause mortality and cardiovascular outcomes using NGT as reference. RESULTS: 618,694 patients were included during a mean follow-up time of 3.9 years. According to the index blood glucose level: 1871 (0.3%) had hypoglycemia, 525,636 (85%) had NGT, 77,442 (13%) had dysglycemia, and 13,745 (2%) patients had hyperglycemia, respectively. During follow-up 44,532 (7.2%) deaths occurred. After multiple adjustments, mortality risk was highest in patients with hypoglycemia HR 2.58 (2.26-2.96) followed by patients with hyperglycemia HR 1.69 (1.63-1.76) and dysglycemia HR 1.16 (1.13-1.19). Risk for cardiovascular events: i.e., myocardial infarction, stroke and heart failure, were highest among patients with hyperglycemia HR 2.28 (2.13-2.44), HR 1.62 (1.51-1.74) and HR 1.60 (1.46-1.75), respectively. CONCLUSION: Patients with disturbed blood glucose level at ED admission have a higher mortality risk than patients with NGT. Patients with hyperglycemia have almost a two folded increased long-term mortality risk and more than a doubled risk for cardiovascular events compared to patients with NGT.

Long-term prognosis in patients with acute myocardial infarction and newly detected glucose abnormalities: predictive value of oral glucose tolerance test and HbA1c.

BACKGROUND: Disturbances of glucose metabolism can be diagnosed by an oral glucose tolerance test (OGTT) and by glycated haemoglobin (HbA1c). The aim of this study was to investigate the association between newly detected disturbances of glucose metabolism and long-term prognosis after acute myocardial infarction (AMI) and to compare the predictive value of an OGTT and HbA1c. METHODS: Patients under the age of 80 years with no known history of diabetes admitted for AMI at the Department of Cardiology, Danderyd University Hospital, Stockholm, Sweden, from January 1st, 2006 until December 31st, 2013, were investigated with an OGTT and a HbA1c before discharge and were classified as having normal glucose tolerance (NGT), prediabetes or diabetes according to American Diabetes Association (ADA) criteria. Using nationwide, all-inclusive registers, patients were followed for the incidence of combined event [CE (first of myocardial infarction, heart failure, ischaemic stroke or mortality)] for a mean follow-up time of 4.8 years. Cox regression analysis was used to calculate Hazard Ratios (HR) and their 95% confidence intervals (CI). RESULTS: Of the 841 patients who were investigated with both an OGTT and a HbA1c, 139 (17%) patients had NGT, 398 (47%) had prediabetes and 304 (36%) had diabetes according to OGTT. The corresponding figures using HbA1c were 320 (38%), 461 (55%) and 60 (7%). Patients with newly discovered diabetes were older and had a higher body mass index compared to those with NGT. OGTT was not predictive for CE. In contrast, prediabetes identified by a HbA1c was associated with an increased risk for CE (HR 1.31; 95% CI 1.05-1.63) compared to normoglycaemia. When comparing the prognostic value of different glucose and HbA1c cut-offs, only a HbA1c ≥ 39 mmol/mol was significantly associated with CE (HR 95% CI; 1.30:1.05-1.61). CONCLUSION: In this single-centre study, in a recent contemporary cohort, we found that around two thirds of the patients admitted with AMI with no known history of diabetes had disturbed glucose metabolism, in accordance with previous studies. HbA1c in the prediabetes range, but not OGTT, added predictive value on the long-term outcome, in a cohort to whom a pathologic OGTT result was communicated with lifestyle advice.

Preoperative disturbances of glucose metabolism and mortality after coronary artery bypass grafting.

BACKGROUND: Disturbances of glucose metabolism are important risk factors for coronary artery disease and are associated with an increased mortality risk. The aim was to investigate the association between preoperative disturbances of glucose metabolism and long-term all-cause mortality after coronary artery bypass grafting (CABG). METHODS: Patients undergoing a first isolated CABG in 2005-2013 were included. All patients without previously known diabetes underwent an oral glucose tolerance test (OGTT) before surgery. They were categorised as having normal glucose tolerance (NGT), pre-diabetes (impaired glucose tolerance and/or impaired fasting glucose) or newly discovered diabetes. Data were collected from nationwide healthcare registers. Cox regression was used to calculate adjusted HR with 95% CI for death in patients with pre-diabetes and diabetes, using NGT as reference. RESULTS: In total, 497 patients aged 40-86 years were included. According to OGTT, 170 (34%) patients had NGT, 219 (44%) patients with pre-diabetes and 108 (22%) patients had newly discovered diabetes. Baseline characteristics were similar between the groups except for slightly higher age among patients with newly discovered diabetes. There were 133 (27%) deaths during a mean follow-up time of 10 years. The cumulative 10-year survival was 77% (69%-83%), 83% (77%-87%) and 71% (61%-79%) in patients with NGT, pre-diabetes and newly discovered diabetes, respectively. There was no significant difference in all-cause mortality between the groups after multivariable adjustment. CONCLUSION: In this study, patients with pre-diabetes or newly discovered diabetes prior to CABG had similar long-term survival compared with patients with NGT.