Outcome of unstable angina in patients with diabetes mellitus

Assessment of demographics, treatment strategies, and evidence-based medicine use among diabetic and non-diabetic patients with acute coronary syndrome: A cohort study

Objectives:

To evaluate and compare clinical and epidemiological characteristics, treatment strategies, and utilization of evidence-based medicine (EBM) among coronary artery disease (CAD) patients with or without diabetes.

Materials and Methods:

Prospective observational cohort study from a tertiary care hospital in India among patients with CAD (myocardial infarction, unstable angina, or chronic stable angina). Data included demographic information, vital signs, personal particulars, risk factors for CAD, treatment strategies, and discharge medications. We evaluated epidemiologic characteristics and treatment strategies for diabetic and non-diabetic patients.

Results:

Of 1,073 patients who underwent angiography, 960 patients (30% diabetic) had CAD. Proportion of hypertensive patients was higher among diabetic patients (58 vs 35% non-diabetic, P < 0.001). Similar proportion of patients received medical management in diabetic vs non-diabetic CAD patients (35 vs 34%, P = 0.091); in diabetics the use of surgical procedure was higher (22 vs 17%, P = 0.0230) than interventional strategy (percutaneous transluminal coronary angioplasty, 43 vs 49%, P = 0.0445). Key medications (antiplatelet agents, angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB), beta-blockers, and ahtihyperlipidemic agents) were prescribed in 95, 53/12, 67, and 91% diabetic (n = 252) and 96, 51/8, 67, and 94% non-diabetic (n = 673) patients, respectively on discharge.

Conclusions:

Clustering of several risk factors at presentation, typically diabetes and hypertension, is common in CAD patients. Though diabetic patients are managed more conservatively, utilization of EBM for diabetic and non-diabetic patients is consistent with the recommendations.

Early invasive strategy and outcomes of non-ST-elevation acute coronary syndrome patients: is time really the major determinant?

In non-ST-elevation acute coronary syndromes (ACS), an early invasive strategy is recommended for middle/high-risk patients; however, the optimal timing for coronary angiography is still debated. The aim of this study was to evaluate the prognostic implications of the time of angiography in ACS patients treated in accord with an early invasive strategy. We analyzed the relationship between the time of angiography and outcomes at follow-up in 517 ACS patients, of whom 482 were revascularized with percutaneous coronary intervention (PCI) (86.9%) or coronary artery by-pass graft (13.1%). We also evaluated the influence of clinical, biohumoral and angiographic variables on the patients' outcomes at follow-up. Among patients submitted to angiography at different time intervals from both hospital admission and symptom onset, significant differences neither in mortality nor in cardiac ischemic events at follow-up were observed. At univariate analysis, complete versus partial revascularization, longer hospital stay, higher TIMI risk score, diabetes mellitus, higher discharge creatinine and admission anemia were associated with mortality and cardiac ischemic events at follow-up; a lower left ventricular ejection fraction was associated with mortality; higher peak troponin I and previous PCI were associated with cardiac ischemic events at follow-up. At multivariate analysis longer hospital stay, higher discharge creatinine levels, and previous PCI were independent predictors of cardiac ischemic events at follow-up. Our evaluation in ACS patients treated with an early invasive strategy does not support the concept that angiography should be performed as soon as possible after symptom onset or hospital admission. Rather, an unfavorable long-term outcome is influenced principally by the clinical complexity of patients.

Pioglitazone induces regression of coronary atherosclerotic plaques in patients with type 2 diabetes mellitus or impaired glucose tolerance: a randomized prospective study using intravascular ultrasound

BACKGROUND

A large clinical trial clarified that pioglitazone reduces cardiovascular events in diabetic patients. However, effects of pioglitazone on structure of coronary atherosclerotic plaques have not been demonstrated. We examined whether pioglitazone reduces volumes of coronary atherosclerotic plaques using intravascular ultrasound (IVUS).

METHODS

Twenty-six consecutive patients with type 2 diabetes mellitus (DM) or impaired glucose tolerance (IGT) undergoing percutaneous coronary intervention (PCI) were enrolled. Echolucent plaques without significant stenosis were selected in IVUS video images at non-PCI-influenced coronary segments and volumetric analysis of the targeted plaques was performed. The patients were randomly assigned into 2 groups: pioglitazone group consisted of 13 patients taking pioglitazone 15 mg/day for initial 14 days after PCI and subsequent 30 mg/day during 6-month follow-up, and control group with 13 patients as control. The plaque volumes and some parameters such as plasma lipid profiles and high-sensitive C-reacting protein (hs-CRP) levels were compared between baseline and the follow-up in those groups.

RESULTS

In the pioglitazone group after 6 months, the plaque volume was significantly reduced (101.3+/-32.1 to 94.6+/-33.6 mm(3), -7.2%; p=0.0023), plasma triglyceride was significantly decreased (- 14.9%) and high density lipoprotein cholesterol was substantially increased (+20.0%) without any significant change in low density lipoprotein cholesterol (LDL-C). Also, hs-CRP level tended to be decreased. However, no significant change in plaque volumes and those parameters was observed in the control group.

CONCLUSIONS

Pioglitazone may induce regression of coronary atherosclerotic plaques without LDL-C reduction in patients with DM and IGT.

Comparison of myocardial reperfusion in patients undergoing percutaneous coronary intervention in ST-segment elevation acute myocardial infarction with versus without diabetes mellitus (from the EMERALD Trial)

Diabetes mellitus is strongly associated with increased cardiovascular morbidity and mortality in patients with ST-segment elevation myocardial infarction. It is unknown whether myocardial perfusion is decreased in diabetic compared with nondiabetic patients after primary percutaneous coronary intervention (PCI), which may contribute to their worse prognosis. We compared myocardial perfusion and infarct sizes between diabetic and nondiabetic patients undergoing PCI for acute ST-segment elevation myocardial infarction in the EMERALD trial. EMERALD was a prospective, randomized, multicenter study evaluating distal embolic protection during primary PCI in ST-segment elevation myocardial infarction. End points included final myocardial blush grade, complete ST-segment resolution (STR) 30 minutes after PCI, and final infarct size as determined by technetium-99m single proton emission computed tomography measured between days 5 and 14. Of 501 patients, 62 (12%) had diabetes mellitus. Diabetic patients had impaired myocardial perfusion after PCI as measured by myocardial blush grade 0/1 (34% vs 16%, p = 0.002) and lower rates of complete 30-minute STR (45% vs 65%, p = 0.005). Infarct size (median 20% vs 11%, p = 0.005), development of new onset severe congestive heart failure (12% vs 4%, p = 0.016), and 30-day mortality (10% vs 1%, p <0.0001) were also greater in diabetic patients. After multivariate adjustment, diabetes remained associated with lack of complete STR and mortality at 6 months. Use of distal protection devices did not improve outcomes in diabetic or nondiabetic patients. In conclusion, in patients with ST-segment elevation myocardial infarction undergoing primary PCI, diabetes is independently associated with decreased myocardial reperfusion, larger infarct, development of congestive heart failure, and decreased survival.

Characteristics and in-hospital mortality of diabetics and nondiabetics with an acute coronary syndrome; the GREECS study

OBJECTIVES

In this work, we sought to describe the baseline characteristics and the management of patients with and without diabetes hospitalized with acute coronary syndromes (ACS), as well as to assess the prognostic value of diabetes status to the severity of ACS and in-hospital mortality.

METHODS

A sample of six hospitals located in Greek urban and rural regions was selected and we recorded almost all admissions due to ACS, from October 2003 to September 2004. 2,172 patients were included in the study. Socio-demographic, clinical, dietary and other lifestyle characteristics was recorded.

RESULTS

Approximately 1 in 3 patients admitted at the hospital with ACS had history of diabetes. Diabetes mellitus was associated with old age, female gender and more prevalent history of coronary heart disease, hypertension and renal failure. Diabetics sought medical care later and they were less likely to receive fibrinolytic therapy. No statistically significant difference was observed on severity of ACS between diabetics and nondiabetics. The in-hospital mortality was higher in diabetics compared to nondiabetics. In a multivariate analysis only insulin-treated diabetics had an increased mortality rate compared to nondiabetics.

CONCLUSIONS

The use of more effective medications and interventions must be used in diabetics who develop ACS, as well as educational efforts should be directed to those patients for reducing the pre-hospital delay.

Diabetic patients with acute coronary syndromes in the UK: high risk and under treated. Results from the prospective registry of acute ischaemic syndromes in the UK (PRAIS-UK)

OBJECTIVES

Short-term randomised trials suggest that patients with diabetes mellitus (DM), admitted with acute coronary syndromes (ACS) are at increased risk of subsequent adverse events. We tested whether this hypothesis was true for an unselected population of ACS patients with and without DM admitted with non-ST elevation MI or unstable angina, in a non-trial setting over a longer term of follow-up.

METHODS

Prospective, centrally, coordinated multicenter registry involving 56 centers throughout the UK (half having angiographic facilities). Consecutive patients admitted with ACS without ST elevation on the presenting ECG were followed up to 6 months. A sub-group of patients were flagged with the UK Office for National Statistics and followed-up for death over 4 years.

RESULTS

Data were collected on 1046 ACS patients of whom 170 (16%) had a prior diagnosis of DM. DM patients had higher baseline co-morbidities and unadjusted mortality rates at 6 months (11.8% vs. 6.4%, p=0.01). After correcting for clinical variables such as age, gender, smoking status and chest pain/ischaemic ECG changes on admission, prior history of any of myocardial infarction, heart failure, hypertension, hypercholesterolemia (on treatment), stroke or coronary revascularisation (PTCA or CABG), mortality rates for DM patients were no longer significantly raised (hazard ratio 1.35, 95% CI: 0.79-2.30; p=0.27 at 6 months and 1.15, 95% CI 0.72-1.83 at 4 years). 30% of diabetics were dead after 4 years of follow-up. Patients with DM were more likely to have been revascularised at 6 months and were more likely to receive ACE inhibitors. Based on the rate of recruitment and the population covered in the study, about 21,000 patients with DM will be admitted with non-ST elevation ACS each year in the UK.

CONCLUSIONS

DM is common amongst patients admitted with ACS without ST elevation and is associated with significant morbidity and mortality: approximately 1 in 8 will not survive up to 6 months and 1 in 3 to 4 years. DM patients should be managed aggressively to reduce their risk of future complications.

Impact of diabetes mellitus on long-term outcome after unstable angina and non-ST-segment elevation myocardial infarction treated with a very early invasive strategy

AIMS/HYPOTHESIS

We sought to evaluate the impact of diabetes mellitus on long-term outcome in patients with unstable angina and non-ST-segment elevation myocardial infarction treated with a very early invasive strategy.

METHODS

We carried out a prospective cohort study in 270 diabetic and 1163 non-diabetic patients with unstable angina and non-ST-segment elevation myocardial infarction. All patients underwent coronary angiography and, if appropriate, subsequent revascularisation within 24 hours of admission. The primary endpoint was all-cause mortality during follow-up for up to 60 months.

RESULTS

Diabetic patients had less favourable baseline characteristics including more advanced coronary artery disease and more severe unstable angina and non-ST-segment elevation myocardial infarction. Percutaneous coronary intervention was performed in 53% of diabetic patients and 56% of non-diabetic patients. Coronary artery bypass grafting was done in 21% of diabetic patients and 12% of non-diabetic patients. In-hospital mortality (4.1% vs 1.3%; hazard ratio 3.47; 95% CI: 1.57 to 7.64; p=0.002) and long-term mortality (9.7% vs 4.9%; hazard ratio 2.11; 95% CI: 1.33 to 3.36; p=0.002) were significantly higher in diabetic patients. After adjustment for differences in baseline characteristics, diabetes mellitus was no longer an independent predictor of long-term mortality (hazard ratio 1.43; 95% CI: 0.74 to 2.78; p=0.292).

CONCLUSIONS/INTERPRETATION

Diabetic patients treated with a very early invasive strategy for unstable angina and non-ST-segment elevation myocardial infarction have a higher in-hospital and long-term mortality that is largely explained by their less favourable baseline characteristics including more advanced coronary artery disease and more severe unstable angina and non-ST-segment elevation myocardial infarction.

[Prognostic value of troponin T in hospitalized patients with angina or non-ST-segment elevation myocardial infarction]

INTRODUCTION AND OBJECTIVES

Cardiac troponins are highly specific and sensitive for detecting minimal myocardial damage. The aim of our study was to determine the prognostic value of troponin T levels in patients hospitalized for suspected angina or myocardial infarction without ST-segment elevation.

PATIENTS AND METHOD

We recorded the frequency of death, acute myocardial infarction, heart failure, or need for coronary revascularization in the three months after the onset of symptoms in 346 consecutive patients admitted for suspected acute coronary syndrome, excluding those who developed myocardial infarction with persistent ST-segment elevation.

RESULT

. Serum troponin T levels were > or = 0.1 ng/ml in 133 patients (troponin T positive group) and lower in 213 patients (troponin T negative group). The relative risk (RR) and 95 percent confidence intervals (95% CI) of individual and grouped events for the troponin T positive group were 3.2 (95% CI, 1.4-7.3; p = 0.006) for death; 2.8 (95% CI, 1.43-5.51; p = 0.003) for death or myocardial infarction; and 2.8 (95% CI, 1.6-5.0; p < 0.001) for death, myocardial infarction or heart failure. Diabetes mellitus and troponin T levels > or = 0.1 ng/ml had independent prognostic value after adjusting for age, sex, and electrocardiographic changes; with RR 2.5 (95% CI, 1.01-5.9) for death, myocardial infarction or heart failure.

CONCLUSIONS

The prognosis of patients hospitalized for chest pain who do not immediately develop transmural necrosis depends on serum troponin T levels at hospital admission. Troponin T levels > or = 0.1 ng/ml almost triple the risk of major events in the three months after the acute episode. The prognostic value of troponin T is independent of age, sex, presence of diabetes mellitus, and electrocardiographic changes.

[Coronary artery surgery in diabetic patients]

Currently, 15% to 30% of the patients that undergo coronary artery surgery are diabetics. As a group, they have less favorable anatomic and clinical characteristics than the general population. Specifically, diabetics have more extensive coronary disease, more vessels involved, and more diffuse stenosis, so they need a higher number of distal anastomoses to achieve complete revascularization. In spite of these drawbacks, they can undergo coronary artery bypass procedures with an operative mortality similar to that of non-diabetic patients. However, some postoperative complications are significantly more prevalent among diabetics, mainly renal failure, neurological accidents, sternal dehiscence, and infection. In early studies of the late results of surgical revascularization, mainly based on venous grafts, late survival and clinical improvement were less satisfactory in diabetics than in non-diabetics. However, in recent experiences, in which the internal mammary artery has been used extensively, the clinical outcome of diabetics has been similar to that of non-diabetics, confirming this procedure as the preferred one in revascularizing the coronary arteries of diabetics with multivessel disease. Off-pump surgery and extensive use of arterial grafts are becoming established strategies for reducing operative risk and improving long-term clinical results. However, continuous, strict medical management of hyperglycemia and other known coronary risk factors, especially lipid levels, is essential.

Cardiac Outcomes After Myocardial Infarction in Elderly Patients With Diabetes Mellitus

• Objective To examine the association between (1) comorbid conditions related to diabetes mellitus, clinical findings on arrival at the hospital, and characteristics of the myocardial infarction and (2) risk of heart failure, recurrent myocardial infarction, and mortality in the year after myocardial infarction in elderly 30-day survivors of myocardial infarction who had non–insulin- or insulin-treated diabetes.

• Methods Medical records for June 1, 1992, through February 28, 1993, of Medicare beneficiaries (n = 1698), 65 years or older, hospitalized for acute myocardial infarction in Connecticut were reviewed by trained abstractors.

• Results One year after myocardial infarction, elderly patients with non–insulin- and insulin-treated diabetes mellitus had significantly greater risk for readmission for heart failure and recurrent myocardial infarction than did patients without diabetes mellitus, and risk was greater in patients treated with insulin than in patients not treated with insulin. Diabetes mellitus, comorbid conditions related to diabetes mellitus, clinical findings on arrival, and characteristics of the myocardial infarction, specifically measures of ventricular function, were important predictors of these outcomes. Mortality was greater in patients not treated with insulin than in patients treated with insulin; the increased risk was mostly due to comorbid conditions related to diabetes mellitus and poorer ventricular function.

• Conclusions Risk of heart failure, recurrent myocardial infarction, and mortality is elevated in elderly patients who have non–insulin- or insulin-treated diabetes mellitus. Comorbid conditions related to diabetes mellitus and ventricular function at the time of the index myocardial infarction are important contributors to poorer outcomes in patients with diabetes mellitus.

Acute myocardial infarction in the elderly with diabetes

OBJECTIVE

Diabetes mellitus (DM) has been associated with an elevated, short-term risk of death after myocardial infarction (MI). Among the studies of DM, however, few studies have included elderly subjects. The purpose of the present investigation was to determine if non-insulin-treated DM (NIRxDM) and insulin-treated DM (IRxDM) were associated with specific comorbid conditions, clinical findings on arrival, and MI characteristics, as well as a higher 30-day mortality rate in elderly patients with acute MI.

DESIGN

The study design was a retrospective medical record review and secondary data analysis of previously collected data from the Cooperative Cardiovascular Project.

SETTING

Study setting was Connecticut from June 1, 1992, through February 28, 1993.

PATIENTS

Subjects included the entire Medicare population (n = 2050), aged 65 years or older who were hospitalized for acute MI.

OUTCOME MEASURES

Mortality rate at 30 days after MI was measured.

RESULTS

A history of DM was observed in 29% of the study population. DM status was associated with previous comorbid conditions, poorer functional status, higher body mass index, heart failure on arrival, non-Q-wave MI, and development of atrial fibrillation and oliguria during hospitalization. Patients with DM were less likely to have chest pain on arrival to the hospital. Diabetic status was not a significant predictor of short-term mortality; at 30 days after MI, 17% (n = 242) of the subjects without DM, 19% (n = 71) of those with NIRxDM, and 18% (n = 39) of the subjects with IRxDM died (P = .460). After adjustment for other prognostic factors, it was noted that MI characteristics present on hospital arrival predicted mortality at 30 days in both patients with NIRxDM and patients with IRxDM.

CONCLUSIONS

The slightly, but not significantly, increased mortality risk in patients with DM should not minimize the importance of monitoring DM in the acute MI setting. Hospitalization for MI provides an opportunity to provide aggressive lipid and blood pressure management, optimize blood glucose, control heart failure, and institute other secondary preventive interventions in the elderly population with DM.

[Prognosis of diabetic patients with ischemic cardiopathy]

The prevalence of diabetes in Spain is about 6% and increases with age and obesity. Diabetes is present in approximately 25% of patients with coronary heart disease (CHD). Pre-diabetic and diabetic patients have a higher incidence of CHD and poorer prognosis, with high short- and long-term mortality. The protective effect of pre-menopause status is suppressed by diabetes. Diabetes has a synergic effect with other cardiovascular risk factors. Primary prevention in diabetic patients should be approached as in non-diabetic post-infarction patients. In diabetes, a healthy life-style and strict control of blood sugar and the other cardiovascular risk factors, particularly hypertension, is mandatory.

Enhanced endothelial activation in diabetic patients with unstable angina and non-Q-wave myocardial infarction

AIMS

Diabetes mellitus (DM) is associated with chronic endothelial dysfunction. Diabetic patients presenting with acute coronary syndromes have a worse prognosis than non-diabetics. An acute inflammatory reaction at the site of coronary plaque rupture and increased expression of surface and soluble cellular adhesion molecules (CAMs) are pathological features of acute coronary syndromes. We set out to characterize the expression of soluble CAMs in patients with and without diabetes presenting with unstable angina (UA) and non Q-wave myocardial infarction (NQMI).

METHODS

Patients presenting with UA and NQMI had serum samples taken on presentation, after 72 h and then 3, 6 and 12 months after discharge. Levels of soluble intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin and P-selectin were measured using an ELISA technique.

RESULTS

We studied 15 diabetic patients and 15 age- and sex-matched non-diabetic patients presenting with either UA or NQMI. Levels of soluble E-selectin were elevated in the diabetic patients in comparison with the non-diabetic patients at all measured time points: 74 +/- 10 ng/ml vs. 47 +/- 3 ng/ml, P < 0.03 at t = 0 h, 55 +/- 5 ng/ml vs. 38 +/- 2 ng/ml, P < 0.02 at t = 72 h. However, levels of soluble P-selectin were lower in the diabetic cohort during follow-up: 134 +/- 15 ng/ml vs. 225 +/- 32 ng/ml, P < 0.02 at t = 3/12 and 112 +/- 8 ng/ml vs. 197 +/- 23 ng/ml, P < 0.02 at t = 6/12. There was no significant difference in levels of soluble ICAM-1 and VCAM-1 between diabetic and non-diabetic patients.

CONCLUSIONS

Levels of soluble E-selectin are significantly elevated in diabetic patients presenting with UA and NQMI in comparison with non-diabetics. This finding may reflect enhanced endothelial activation which may contribute to the adverse prognosis of diabetic patients with acute coronary syndromes.

Cardiovascular drug use and hospitalizations attributable to type 2 diabetes

OBJECTIVE

To investigate cardiovascular drug use and hospitalizations attributable to type 2 diabetes from 1 year before until 6 years after the start of oral antidiabetic therapy.

RESEARCH DESIGN AND METHODS

In this cohort study, 2,584 patients with type 2 diabetes were selected from the PHARMO Record Linkage System, comprising pharmacy records and hospitalizations for all 320,000 residents of six Dutch cities. Patients with type 2 diabetes were identified as incident oral antidiabetic drug users between 1992 and 1997. Nondiabetic subjects were 1:1-matched for age, sex, pharmacy, and index date and received no insulin, oral antidiabetic drugs, or glucose-testing supplies.

RESULTS

Patients with type 2 diabetes were more likely to use cardiovascular drugs (RR 1.28 [95% CI 1.23-1.34]) and to be hospitalized because of cardiovascular diseases (1.54 [1.33-1.78]) after the start of oral antidiabetic therapy than nondiabetic subjects. Differences between patients with type 2 diabetes and nondiabetic subjects lessened from 1 year before until 6 years after the start of oral antidiabetic therapy, reflected by decreasing attributable risks for diuretics, beta-blockers, calcium channel blockers, and cardiac and antithrombotic drugs. The difference in use of angiotensin-converting enzyme inhibitors and lipid-lowering drugs increased. Cardiovascular hospitalizations attributable to type 2 diabetes were approximately 50% in the years close to the start of oral antidiabetic treatment and decreased to approximately 33% in the following years.

CONCLUSIONS

Although cardiovascular drug use and hospitalizations remained increased in patients with type 2 diabetes after the start of oral antidiabetic therapy, cardiovascular drug use attributable to type 2 diabetes decreased after the start of oral antidiabetic therapy, especially beta-blockers, whereas cardiovascular hospitalizations first decreased and then stabilized.

[The role of diabetes mellitus in cardiac disease in Spain. The CARDIOTENS Study 1999]

BACKGROUND

We analyse the characteristics of the patients with diabetes and cardiac disease included in the CARDIOTENS 1999 study.

PATIENTS AND METHOD

32,051 outpatients who were seen the same day by 1,159 primary healthcare physicians (79%) and cardiologists (21%) were prospectively registered in a database including demographic and clinical data and therapeutic profile.

RESULTS

History of cardiac disease was present in 19% (6,194 patients) of the whole population, and 1,275 of them (20.6%) were diabetics. Hypertension was present in 74% of diabetic patients with cardiac disease. Coronary heart disease (angina pectoris or previous myocardial infarction) was present in 45% of diabetic patients with heart failure. Less than 30% of these patients had blood pressure levels under 130/85 mmHg, as recommended by international guidelines. An LDL-cholesterol level lower than 100 mgrs/dl was observed in only 12% of diabetic patients with coronary heart disease; the mean values of total cholesterol and LDL-cholesterol of these patients were significantly (p < 0.01) higher in those seen by primary healthcare physicians. Less than 40% of diabetic patients with cardiac disease were treated with an angiotensin converting enzyme inhibitor, a therapy which was otherwise used in 50% of diabetic patients with heart failure. A beta-blocker therapy was used in 26% of diabetic patients with coronary heart disease and 39% of them were being treated with statins.

CONCLUSIONS

More than 20% of patients with cardiac disease in this study were diabetics. Blood pressure and cholesterol levels recommended by current guidelines were attained in a limited proportion of these patients. The use of drugs with demonstrated prognostic benefit in diabetic patients with heart disease is scarce.

Beneficial and detrimental effects of intensive glycaemic control, with emphasis on type 2 diabetes mellitus

Diabetes mellitus is a major health problem in the world. Several clinical trials have shown that some of the major complications of diabetes mellitus can be partially prevented or delayed by intensive glycaemic control. However, there are benefits and risks in aiming for near normal blood glucose levels. Intensive glycaemic control delays the onset and progression of retinopathy, nephropathy and neuropathy. Epidemiological and observational studies have shown that cardiovascular events may be correlated with the severity and duration of diabetes mellitus, but major randomised trials have only shown weak and nonsignificant benefits of intensive glycaemic management in decreasing event rates. A modest improvement in lipid profile results from blood glucose control although, in the majority of cases, not enough to reach current targets. Detrimental effects of intensive glycaemic control include bodyweight gain and hypoglycaemia. Controversial issues in the management of patients with diabetes mellitus include the unproven increase in cardiovascular morbidity from sulphonylureas and hyperinsulinaemia, and the still unknown long term effects of newer oral antihyperglycaemic agents alone or in combination with traditional therapies (such as sulphonylureas and metformin). It is important to individualise management in setting glycaemic goals. Control of cardiovascular risk factors through blood pressure and lipid control and treatment with aspirin (acetylsalicylic acid) and ACE inhibitors have consistently shown benefits in the prevention of both macro- and microvascular complications in patients with diabetes mellitus; these measures deserve priority.

Prognostic significance of diabetes as a predictor of survival after cardiac catheterization. APPROACH Investigators. Alberta Provincial Program for Outcome Assessment in Coronary Heart Disease

PURPOSE

Diabetes is a recognized risk factor for the development of cardiac disease, but its importance as a prognostic factor among patients with known cardiovascular disease is less clear. We evaluated survival in patients with and without diabetes who underwent cardiac catheterization for presumed coronary artery disease.

SUBJECTS AND METHODS

We analyzed data from a prospective cohort study that captures detailed clinical information and longitudinal outcomes for all patients who undergo cardiac catheterization in Alberta, Canada. We studied 11,468 patients, 1959 (17%) of whom had diabetes. Logistic regression was used to model predictors of 1-year mortality, and proportional hazards analysis was used to model predictors of survival up to 3 years after cardiac catheterization.

RESULTS

One-year mortality was 7.6% for patients with diabetes versus 4.1% for those without diabetes (odds ratio = 1.9, 95% confidence interval [CI]: 1.6 to 2.3). After adjusting for other characteristics of the patients, including comorbid conditions, previous cardiac history, coronary anatomy, and renal function, the odds ratio for 1-year mortality was 1.1 (95% CI: 0.8 to 1.3). Similarly, the adjusted hazard ratio for longer term mortality was 1. 2 (95% CI: 1.0 to 1.4, mean follow-up of 702 days).

CONCLUSIONS

These results suggest that there is little or no independent association between diabetes and mortality for up to 3 years after cardiac catheterization. Estimates of short- to intermediate-term prognosis for diabetic patients with coronary artery disease should be based on the presence of other prognostic factors associated with diabetes.

Impact of diabetes on long-term prognosis in patients with unstable angina and non-Q-wave myocardial infarction: results of the OASIS (Organization to Assess Strategies for Ischemic Syndromes) Registry

BACKGROUND

Although unstable coronary artery disease is the most common reason for admission to a coronary care unit, the long-term prognosis of patients with this diagnosis is unknown. This is particularly true for patients with diabetes mellitus, who are known to have a high morbidity and mortality after an acute myocardial infarction.

METHODS AND RESULTS

Prospectively collected data from 6 different countries in the Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry were analyzed to determine the 2-year prognosis of diabetic and nondiabetic patients who were hospitalized with unstable angina or non-Q-wave myocardial infarction. Overall, 1718 of 8013 registry patients (21%) had diabetes. Diabetic patients had a higher rate of coronary bypass surgery than nondiabetic patients (23% versus 20%, P:<0.001) but had similar rates of catheterization and angioplasty. Diabetes independently predicted mortality (relative risk [RR], 1.57; 95% CI, 1.38 to 1.81; P:<0.001), as well as cardiovascular death, new myocardial infarction, stroke, and new congestive heart failure. Moreover, compared with their nondiabetic counterparts, women had a significantly higher risk than men (RR, 1.98; 95% CI, 1.60 to 2.44; and RR, 1.28; 95% CI, 1.06 to 1.56, respectively). Interestingly, diabetic patients without prior cardiovascular disease had the same event rates for all outcomes as nondiabetic patients with previous vascular disease.

CONCLUSIONS

Hospitalization for unstable angina or non-Q-wave myocardial infarction predicts a high 2-year morbidity and mortality; this is especially evident for patients with diabetes. Diabetic patients with no previous cardiovascular disease have the same long-term morbidity and mortality as nondiabetic patients with established cardiovascular disease after hospitalization for unstable coronary artery disease.

Blood glucose and platelet-dependent thrombosis in patients with coronary artery disease

OBJECTIVES

To investigate the influence of blood glucose on platelet-dependent thrombosis (PDT).

BACKGROUND

Elevated blood glucose is a predictor of adverse cardiovascular risk independent of a diagnosis of diabetes, possibly due to adverse effects promoting thrombosis. The effects of blood glucose on PDT have not been characterized.

METHODS

An ex vivo extracorporeal perfusion protocol was used to measure PDT in 42 patients with stable coronary artery disease (CAD). The Badimon chamber was perfused with unanticoagulated venous blood and PDT evaluated using computerized morphometry. Whole blood impedance aggregometry and flow cytometry evaluated platelet aggregation and P-selectin expression, respectively.

RESULTS

Using a multivariate stepwise regression model, blood glucose was the best independent predictor of PDT (R2 = 0.19, p < 0.008), followed by apolipoprotein B (R2 = 0.18, p = 0.002) and intracellular magnesium levels (R2 = 0.12, p = 0.02). Platelet-dependent thrombosis was significantly greater in patients with blood glucose >, compared with <, the median value of 4.9 mmol/l (159 +/- 141 vs. 67 +/- 69 microm2/mm, p < 0.01). Neither platelet aggregation nor P-selectin expression was significantly different between the two groups. Insulin levels correlated with blood glucose (r = 0.56, p = 0.0003), but were not independently associated with either PDT, platelet aggregation or P-selectin expression. A two-way analysis of variance demonstrated an interaction between insulin (>126 pmol/l) and blood glucose (>4.9 mmol/l) in modulating PDT (F [1,38] = 8.5, p < 0.006).

CONCLUSIONS

Blood glucose is an independent predictor of PDT in stable CAD patients. The relationship is evident even in the range of blood glucose levels considered normal, indicating that the risk associated with blood glucose may be continuous and graded. These findings suggest that the increased CAD risk associated with elevated blood glucose may be, in part, related to enhanced platelet-mediated thrombogenesis.