Abstract
The global prevalence of diabetes mellitus has continuously and rapidly increased, and the number of diabetic people in the adult population is predicted to double within 30 years. The prevalence of and mortality from all forms of cardiovascular diseases is two- to eight-fold higher in diabetic individuals as compared with their non-diabetic counterparts. The excess of risk attributable to diabetes related heart disease accounts for 2.9% of the all cause annual mortality. Moreover, the cardiovascular risk increases continuously throughout a wide spectrum of glycaemia starting already at what, according to present definitions, is considered as normal blood glucose levels. Therefore, screening for diabetes and hyperglycaemia is recommended in various clinical settings. Criteria for classification of hyperglycaemic states are provided together with their relation to risk for cardiovascular events. The evidence-based treatment of cardiovascular disease in patients with concomitant diabetes is summarised. Degree of under-treatment of patients with diabetes and cardiovascular diseases is discussed. Finally, the potential impact that nurses may have on the quality and efficacy of care in the vulnerable patient with combined chronic diseases such as diabetes and cardiovascular disease and the improvement of the outcomes are discussed.
Diabetes mellitus—prevalence
The global prevalence of diabetes mellitus has increased during the last period of time and it will continuously and rapidly continue to increase during the next decades. Type 2 diabetes, comprising approximately 90% of adults with diabetes, is the predominant type. In the year 1995 the global prevalence of diabetes mellitus was estimated to be 4.0% in the adult population and it is predicted to increase to 5.4% in 2025 [1] and exceed 7% in 2050 [2]. Accordingly, the number of diabetic individuals is to double within 30 years reaching 300 millions in the year 2025. The highest incidence of adult onset diabetes is expected above the age of 65 years in the developed countries, while the majority of affected individuals in the developing countries will belong to the middle-aged population, 40–65 years of age [3].
Relations between glucose metabolism and cardiovascular disease
Individuals with diabetes are at high risk for cardiovascular disease in the form of coronary heart disease, heart failure, and cerebrovascular disease as well as peripheral artery disease. It was epidemiological data, published in 1979 and originating from the Framingham study that for the first time demonstrated a two- to four-fold increased risk of developing angina pectoris and myocardial infarction in diabetic patients [4]. Subsequently, the Multiple Risk Factor Intervention Trial revealed the relative risks of 3.0 for coronary vascular death and 3.2 for development of coronary heart disease in diabetic participants as compared with their non-diabetic counterparts [5]. The overall burden of heart disease related to diabetes has not improved since then. Accelerated, premature atherosclerosis contributes to 75% of deaths among individuals with both type 1 and type 2 diabetes mellitus. It accounts for 2.9% of the all cause annual mortality and 1.4% from all vascular causes, as shown by Kanters et al. in a meta-analysis of 27 prospective studies conducted from 1966 onwards [6].
Type 2 diabetes is commonly associated with a whole range of cardiovascular risk factors, such as: hypertension; abdominal obesity; highly atherogenic dyslipidemia characterised by low HDL-cholesterol, high triglycerides and the presence of small-dense LDL particles and a prothrombotic state, comprising platelet dysfunction, impaired fibrinolytic activity and increased fibrinogen levels [3,4,7]. Abnormal glucose metabolism is also followed by some specific, unfavourable features affecting the cardiovascular system, among which microalbuminuria, autonomic neuropathy, endothelial dysfunction and diabetic cardiomyopathy are part. Thus, the excess of risk is caused by multiple influences amplifying the impact of coexisting classical risk factors, the direct effects of hyperglycaemia and possibly also other, still not well understood mechanisms, related to the diabetic state in itself [3,7–9].
There is growing evidence that the cardiovascular risk increases continuously throughout a wide spectrum of glycaemia starting already at blood glucose values, that as outlined below according to present definitions, are regarded as normal [9–12]. A systematic overview of 20 studies following over 95000 patients for 12 years indicated a positive relationship between glucose levels and cardiovascular events. This was apparent for glycaemia within the normal range with the relative risk of 1.33 for a fasting blood glucose (FBG) of 6.1 vs. 4.2 mmol/l, and a risk ratio of 1.58 when 2-h post-load glucose levels were compared (6.1 vs. 7.8 mmol/l) [8]. Data from the longitudinal Whitehall, the Paris Prospective and DECODE studies show that the risk of developing cardiovascular disease is almost doubled in subjects with impaired glucose tolerance (IGT) compared with those with normal glucose metabolism [12–14]. As the classification of diabetes has been established on the basis of blood glucose threshold indicating increased risk of microvascular complications only, the diagnostic criteria may be inappropriate for predicting development of macrovascular complications [15]. However, in the lack of controlled clinical trials we cannot be certain whether the cardiovascular risk related to diabetes in fact already starts to become expressed at dysglycaemic glucose levels [9]. Still it is very likely that the state of impaired glucose metabolism, especially when accompanied by other attributes of the so-called metabolic syndrome, contributes to accelerated atherosclerosis, causing substantial cardiovascular system damage even and probably long before the onset of overt diabetes.
There are rapid changes to be observed in the epidemiology of cardiovascular diseases. In the developed countries the dominating features are an ageing population, increasing body mass and decreasing physical activity. In the developing regions a rapid economical transition results in substantial lifestyle changes including a reduction of physical activity and increased prevalence of obesity due to increased availability of energy-dense and rich in saturated-fat food forms combined with expanding smoking habits. These demographic and economic changes favour clustering of classical cardiovascular risk factors, which promote development of both atherosclerosis and type 2 diabetes mellitus already at young age. Currently, the prevalence of some degree of abnormal glucose tolerance (from IGT to overt diabetes) is estimated as 20% in the middle-aged, and up to 35% in the elderly of the American population. Approximately 25% of individuals with newly diagnosed type 2 diabetes already have manifestations of cardiovascular disease [7].
The most recent European data on secondary prevention obtained in the EUROASPIRE II survey disclosed, that 28% of patients with established diagnosis of coronary artery disease have either a history of diabetes or meet diagnostic criteria for diabetes based on blood glucose testing [16]. It means that at least one in four–five patients treated by cardiologists have diabetes, either known or to be disclosed by the recommended blood glucose testing.
In a systematic comparison by Haffner et al., the incidence of the first acute myocardial infarction among diabetic patients during 7 years was equal to the reinfarction rate in non-diabetic survivors of a previous infarct (20.2% vs. 18.8%, respectively) [17]. It may be concluded that a diagnosed diabetes comprises a cardiovascular burden equal to that of a previous myocardial infarction. Consequently an aggressive management of cardiovascular risk factors must be introduced in all patients with diabetes according to present recommendations for secondary prevention [12,18,19]. Moreover, the relative risk for coronary death in patients with diabetes, as calculated by Lee et al. from 16 prospective cohort studies, revealed the actual risk score to be significantly higher for diabetic women than men with an actual risk, adjusted for other risk factors, of 2.58 and 1.85, respectively [20]. In summary diabetes mellitus must be considered a diagnosis of ominous importance in cardiovascular medicine. It is related to an increased mortality and morbidity causing numerous hospital admissions, a higher incidence of heart failure and an unfavourable prognosis in general.
The main cardiovascular diagnosis in relation to diabetes
Acute myocardial infarction
There is a strong relationship between the incidence of an acute myocardial infarction and the presence of abnormal glucose metabolism (comprising overt diabetes and prediabetic state) [11,18,19,21]. The most recent Swedish GAMI study investigated the glucometabolic state of patients admitted to a coronary care unit due to an acute myocardial infarction. Among consecutive patients, who were all free from a history of diabetes mellitus, on admission only 34% had normal glucose tolerance at discharge. Newly detected diabetes occurred in 31% of the patients while IGT was disclosed in the remaining 35% [22]. The in-hospital mortality in patients with diabetes is approximately twice that in non-diabetic subjects [18,23–26]. The OASIS registry (the Organisation to Assess Strategies for Ischemic Syndromes), which followed patients admitted due to acute coronary syndrome event (without persistent ST-segment elevation) showed, that diabetes mellitus was an independent predictor for cardiovascular death, stroke, congestive heart failure and non-fatal reinfarction during the 2 years follow-up, with the risk ratios: 1.49, 1.45, 1.41, 1.34, respectively [25]. Another study addressing acute coronary syndromes GUSTO-IIb, showed that diabetes was associated with a significantly higher risk of death and reinfarction within 30 days after an acute coronary event (13.1% vs. 8.5%) with an increase of 2.9% in absolute mortality among diabetic individuals [26]. After 6 months the diabetic patients experienced a significantly higher (re)infarction rate of 18.8% compared with 11.4% in those without diabetes [26].
The dismal prognosis in patients with diabetes results probably originates from their more diffuse and multivessel coronary artery disease and specific myocardial vulnerability related to disturbed metabolic conditions. Diabetes is associated with hyperglycaemia, increased turnover of free fatty acids, decreased glycolysis rate, increased oxygen demand, which causes impairment of ATP-dependent ion-pumps and deleterious calcium overload. These phenomena promote arrhythmia, contribute to contractile dysfunction and attenuate the protective mechanisms of precondition (4). Sudden cardiac death is significantly more frequent in patients with diabetes (1.5 times in men and 3 times in women) compared with their non-diabetic counterparts [27].
The importance of metabolic balance and appropriate correction of the abnormalities associated with impaired glucose metabolism in patients with acute coronary syndromes and diabetes were first recognised by the DIGAMI study [28]. Early institution of insulin–glucose infusion followed by intense insulin treatment and maintained for at least 3 months, resulted in a 30% reduction of 1-year mortality, a benefit that was sustained for further 3.4 years of follow-up [29].
Despite considerable improvements achieved in treatment of cardiovascular diseases, there is a major disparity in benefits, experienced by diabetic subjects compared with their non-diabetic counterparts. The analysis of coronary artery disease mortality in a US population in 1971–1984 revealed a clear contrast between patients with and without diabetes. The decline achieved in age-adjusted heart disease mortality in non-diabetic men (−36.4%) and women (−27%) differed substantially from a very modest decline observed in diabetic men (−13.1%) and an actual increase in cardiovascular mortality in diabetic women (+23%) [30]. This is alarming evidence that patients with diabetes, who are already burdened with poor prognosis, have hardly experienced any advantages from recent therapeutic achievements.
Heart failure
Diabetic cardiomyopathy is characterised by a predominant impairment of diastolic dysfunction and loss of compensatory response to myocardial ischemia or injury [31]. The prevalence of congestive heart failure among men and women with diabetes is 4 and 8 times higher, respectively, than in non-diabetic subjects [4]. Follow-up data from over 300 diabetic patients participating in the GUSTO trial indicated an almost doubled frequency of heart failure despite the same left ventricular ejection fractions in both diabetic and non-diabetic participants at baseline [26]. An increased prevalence of heart failure in elderly subjects with type 2 diabetes was recently described in an Italian population-based epidemiological study. The incidence of type 2 diabetes during follow-up was higher among subjects, who presented with failure at baseline [32]. Moreover, the risk of developing heart failure during follow-up increased in both the diabetic and the non-diabetic cohort by 15% for a 1% increase in HbA1c at baseline [33]. Thus, heart failure and type 2 diabetes seem to be closely interrelated. The interventions, which may delay progression of diabetic cardiomyopathy and eventually improve prognosis, remain undefined. Recent data report that insulin based improved metabolic control can augment diastolic function in diabetic patients [34].
Definition of diabetes
According to the World Health Organisation (WHO) classification from 1998 (Table 1) the following categories of hyperglycaemia are identified: Diabetes mellitus, IGT and impaired fasting glycaemia (IFG) [35,37]. Diagnosis of diabetes mellitus is made on the basis of medical history, symptoms, blood glucose measurements, casual or fasting, or an oral glucose tolerance test (OGTT) (Table 2). It is required that the criteria are met on at least two occasions and on separate days. The evidence available from population studies allows the recognition of diabetes also if a single plasma glucose measurement within the diabetic range is accompanied by typical symptoms of diabetes, or HbA1c⩾6.5%, or unequivocal diabetic retinopathy [36,37].
Criteria for classification of hyperglycaemic states [35]
00034-8-table1.png)
Criteria for classification of hyperglycaemic states [35]
All values refer to venous plasma glucose concentration expressed in ‘mmol/l’. Note that the reference values for whole venous blood and capillary blood are different [37].
For clinical purposes, in the absence of unequivocal hyperglycaemia with acute metabolic decompensation, these criteria should be confirmed by repeating testing on another day.
OGTT to be performed in the morning, after overnight fasting using a glucose load containing equivalent of 75 g anhydrous glucose dissolved in 300 ml of water ingested over 3–5 min.
Algorithm for diagnosis of hyperglycaemic state [37]
00034-8-table2.png)
All values refer to venous plasma glucose concentration expressed in ‘mmol/l’. Note that the reference values for whole venous blood and capillary blood are different [37].
Regarding the cardiovascular risk, diagnosis of diabetes mellitus is said to be equivalent to a previous myocardial infarction. This primarily endocrine diagnosis indicates twice or even eight times higher risk for subsequent cardiovascular event and premature mortality than in non-diabetic individuals [38]. Therefore, the diagnosis should trigger implementation of a comprehensive, intensive treatment aiming to efficient modification of the coexisting risk factors and improvement of the otherwise ominous prognosis. Early recognition of hyperglycaemia should be followed by introduction of intensive measures in the form of pharmacological intervention, counteraction against accompanying risk factors and modification of adverse lifestyle patterns. This task constitutes a major challenge for health care professionals. An early recognition of high risk individuals is a unique opportunity to implement well targeted preventive actions in less advanced stages of the disease.
Screening for diabetes is regarded cost effective in clinical practice in adults who have more than one cardiovascular risk factor including age [39–41]. In case of patients, who have already been referred to a cardiovascular specialist, it should be a routine element of the relative cardiovascular risk evaluation [18,36,38]. It is reasonable to perform FBG measurements in patients seen in any cardiovascular outpatient clinic or who are admitted to wards of cardiology, neurology, and vascular surgery. If this is not possible, then random blood glucose testing or eventually HbA1c may be considered. A systematic meta-analysis revealed that stress hyperglycaemia assessed by glucose concentration on hospital admission predicted long-term unfavourable outcome. Non-diabetic patients with glucose concentrations in the range of 6.1–8.0 mmol/l had a 3.9-fold higher risk of death. Glucose values of 8.0–10.0 were associated with increased risk of congestive heart failure or cardiogenic shock [42]. Testing for hyperglycaemia is feasible and relevant even in patients admitted with an acute myocardial infarction, as proven by the GAMI study [22]. In case of acute hospital admissions, like acute myocardial infarction, measurements of fasting plasma glucose can be recommended at least on admission and before discharge. An OGTT can be performed already on the fourth day since the acute admission, and the results are not significantly different from subsequent tests made during 1 year of follow-up.
Recommendations for patient management
In contrast to many reports on the increasing prevalence of type 2 diabetes and the enhanced risk for concomitant heart disease, studies comparing different treatment regimens are sparse or lacking. There are few truly randomised-controlled trials addressing this patient population. The knowledge of evidence-based treatment is limited to the results of the UKPDS, DIGAMI, MICRO-HOPE and the recent LIFE studies [3,21,43–45]. So far the DIGAMI study is the only available trial, that addressed a management strategy for diabetic patients with manifest ischemic heart disease. Otherwise the conclusions on management strategies and patient prognosis have to rely on observational studies, registries and post hoc subgroup analysis from existing trials. Accordingly, the results may not be applicable to the common diabetic patient as seen in clinical practice [46,47]. Still it is the best evidence available.
In general it is accepted that evidence-based treatment for patients with coronary artery disease should be applied, on equal grounds, also to individuals with diabetes. However, in the presence of diabetes, the benefits are reduced either due to the metabolic disease itself or other associated factors not yet identified [18,48–50]. There is growing evidence that maintenance of optimal metabolic control, including meticulous blood glucose control improves the outcome of standard cardiological treatment in diabetic patients [3,28,29].
Coronary interventions
Data from large registries on acute coronary syndromes show that early reperfusion remains the most important factor improving the outcome also in the diabetic patient [49–51]. Available revascularisation techniques, by-pass surgery (CABG) and percutaneous coronary intervention (PCI), are associated with poorer outcome and reduced life expectancy in patients with diabetes than in non-diabetic subjects. PCI in subjects with diabetes is associated with a significantly increased risk of procedural myocardial damage, subsequent restenosis and long-term mortality [28,29,52,53]. A surgical coronary revascularisation among patients with diabetes mellitus and multivessel coronary artery disease was associated with a significantly improved survival than that following PCI, with a cardiac mortality of 5.8% vs. 20.6%, and a better overall 10-year survival after CABG (69%) than PCI (46%) [54]. Implementation of new techniques such as stents and drugs like GPIIb/IIIa inhibitors and new platelet ADP receptor antagonists may offer improved outcome, as demonstrated in PCI-CURE study [57]. The most recent observations indicate that lack of adequate metabolic control may actually play an important role by blunting the effects of preconditioning, and potentially contributing to myocardial damage in diabetic patients undergoing revascularisation procedures [3,49,54–57]. Very strict metabolic control at least during the period at highest risk for restenosis (3–6 months after PCI) may also help to improve the outcomes of diabetics after percutaneous interventions [58,59].
Pharmacological treatment
Several established pharmacological interventions seem to decrease mortality and delay the progression of cardiovascular disease in diabetic patients.
ACE inhibitors
In the GISSI trial recruiting patients with acute myocardial infarction the ACE-inhibitor lisinopril caused a reduction of mortality at 6-week from 12.4 to 8.7% and this effect remained at 6-month (12.9% vs. 16.1%) [60,61].
The HOPE trial tested addition of 10 mg of ramipril to existing treatment in patients at high risk for cardiovascular events. Among them were subjects with diabetes and one further risk factor, usually hypertension. The diabetic subgroup had a reduction of total death (−24%), cardiovascular death (−37%), myocardial infarction (−22%) and stroke (−33%) during 4.5 years treatment [44]. Moreover, there was a reduction of microvascular complications (combined endpoint: overt nephropathy, dialysis or laser therapy) by 16% (MICRO-HOPE) [44]. Finally, enalapril improved life expectancy in patients with heart failure in the CONSENSUS and SOLVD trials [62,63].
Angiotensin II receptor antagonists
The angiotensin II receptor antagonists losartan, when compared to the beta-blocker atenolol induced a further reduction of cardiovascular mortality and morbidity (composite endpoint in patients with diabetes, hypertension and left ventricular hypertrophy after 4.7 years of follow-up (18% vs. 23%; adjusted risk reduction −4%) including a reduction of mortality from cardiovascular (13.6% vs. 21.8%) and all causes [45,46].
Beta-blockers
The overall impression from several trials is that diabetic subjects are those who in particular benefit mortality reductions when given beta-blockers (30–40%) post myocardial infarction. The relative reduction amounts to 25–30%. Moreover, beta-blocker treatment counteracts the unfavourable, heart rate increasing effect of autonomic dysfunction that is commonly seen in diabetic patients. Moreover, beta-blockade redirects myocardial metabolism from free fatty acid towards glucose utilisation [3,18,60,64].
Acetylsalicylic acid
As in non-diabetic subjects with coronary artery disease acetylsalicylic acid reduces the likelihood for myocardial infarction, stroke and vascular deaths [65,66].
Treatment strategies
In case of patients with cardiovascular disease and diabetes (or other categories of hyperglycaemia) it is necessary to apply a comprehensive treatment strategy comprising an aggressive treatment of cardiovascular disease, optimal management of the diabetic state (or IGT related hyperglycaemia) together with interventions aiming for efficient control of the classical risk factors. This requires a structured program involving different categories of health care professionals and often several specialities [67–69].
An aggressive therapy is to prepare for chronic disease management, which includes medical counselling by doctors and specialised nurses, education of patients and relatives and thorough risk factor monitoring and repeated check-ups of the interim results of different measures taken. In various clinical settings (from general practice, specialised outpatient service, vascular surgery, cardiology ward to the intensive care unit) it is the nurses who spend most time to care for and offer support for the patients. Accordingly, the performance of nurses will have a substantial impact on the quality and the efficacy of care especially as patients with chronic diseases, such as coronary heart disease, heart failure, peripheral artery disease and diabetes are concerned [70–72]. Their knowledge, experience and skills are inevitably needed if the outcomes of patients with diabetes and cardiovascular disease are to be improved.
Risk factor management
Hypertension and related renal function impairment
Hypertension affects approximately 70% and microalbuminuria 20–30% of the diabetic population. It has been estimated that an increase of systolic blood pressure (BP) by 10 mmHg increases the risk for cardiovascular events by 20% [73]. Microalbuminuria doubles the relative cardiovascular risk and macroalbuminuria increases it by 5 times. Therefore, BP should be tightly controlled aiming at a systolic BP<135 and a diastolic <85 mmHg. In the presence of impaired renal function, microalbuminuria or nephropathy a treatment goal of 120/80 mmHg has been advocated [4,18,74]. Adequate BP control usually requires administration of a combination of several BP lowering drugs. Those generally recommended are ACE inhibitors, beta-blockers, diuretics and recently evaluated angiotensin receptor blockers [3,45,46,60]. Vasoselective calcium-channel antagonists may be added if these drugs fail to satisfactorily control BP. Alpha-blockers or calcium-channel antagonists are not recommended as initial therapy [3,18,60] (Table 3).
Goals for risk factor management in patients with diabetes mellitus
00034-8-table3.png)
Goals for risk factor management in patients with diabetes mellitus
HbA1c-DCCT standardised.
In serum.
BMI⩾25 kg/m2, waist ⩾94 cm (men), ⩾80 cm (women).
Diabetes mellitus is commonly associated with dyslipidemia including a combination of low HDL-cholesterol, high triglycerides and the presence of highly atherogenic small-dense LDL-cholesterol particles. According to several primary and secondary prevention trials with statins, diabetic patients experience similar benefits from lipid lowering as their non-diabetic counterparts, on average causing a 25% risk reduction as regards cardiovascular events [3,18,75–79]. Such treatment does not always normalise the triglycerides. Addition of fibrates to the pharmacological therapy should be considered if the patient still has high triglycerides following dietary and metabolic measures.
Metabolic intervention
As reviewed blood glucose and elevated HbA1c are risk factors already acting at rather low levels [3,9,12,14]. The risk has been calculated to increase approximately 10–30% for a 1% increase in HbA1c [6,7,80] and optimal glucometabolic control may counteract the deleterious effects [3,58,70]. Strict glycaemic control during 5 years was associated with a reduction of cardiovascular events by 28% for the first and 16% for myocardial infarction in the UKPDS study, recruiting diabetic patients at low cardiovascular risk [81]. Moreover, strict insulin based metabolic control in diabetic patients after a myocardial infarction, as applied in the DIGAMI study, resulted in a sustained 29% reduction in total mortality during 3.4 years of follow-up [21,22]. In other words the DIGAMI strategy saved one life for every nine patients treated.
Atrial fibrillation and prothrombotic state
Atrial fibrillation (AF) is especially frequent among patients with diabetes mellitus, who constitute up to 10% of all individuals with AF [82]. The coexistence of AF and diabetes increases the relative risk for ischemic stroke and thromboembolic events by 1.7 times. The reasonable explanation is the impaired platelet function and decreased spontaneous fibrinolytic capacity that characterises patients with diabetes. The most recent guidelines for the management of patients with AF strongly underlines the importance to anticoagulate diabetic subjects aged ⩾60 years keeping the INR level between 2.0 and 3.0 with an addition of 80–160 mg aspirin daily [18,82].
Lifestyle modification
Although not easily accomplished reduction of overweight, abdominal obesity, physical inactivity and unfavourable nutritional habits is a powerful intervention, which may reduce the onset of cardiovascular disease and its complications [83,84]. Moreover, it has recently been proven that lifestyle modification reduces the onset of diabetes mellitus. Two independent randomised trials applied intense lifestyle modification in patients with elevated post-load plasma glucose concentrations (IGT). In a Finnish study subjects randomised to a combination of weight reduction, decreased intake of fat (including saturated fat), increase intake of fibres and regular physical activity during 4 years had a reduction of the onset of diabetes by 58% when compared to individuals in the control group [85]. A similar hypothesis was tested in 3234 Americans, who were randomised to intense lifestyle intervention or metformin (850 g twice daily) or to the control group. Lifestyle intervention aiming at least at a 7% weight loss combined with at least 150 min of physical activity a week, was proven the most efficient treatment, reducing the incidence of diabetes by 58% during 2.8 years of follow-up. The corresponding reduction was 31% in the metformin subgroup [86]. This proves the value of meticulous defined therapeutic goals and that structured education and forcefully implemented rehabilitation programs indeed are very successful.
Poor treatment of diabetic patients
The poor prognosis in diabetic patients with established heart disease is a matter of serious concern. Reasons for the lack of improvement seen in this vulnerable group has not been well investigated and thereby understood. Recent reports originating from different European countries disclose that there is a substantial degree of under treatment affecting diabetic patients. This comprises inadequate dosing and restricted prescription of certain evidence-based therapy, inefficient modification of risk factors, lack of metabolic control and ineffective rehabilitation programs [71,87–89]. A British population-based survey revealed for instance that one-third of diabetic individuals did not receive any hypertensive medication and more than half of those, who were treated had still poorly controlled BP (>160/95 mmHg). Moreover, at least one-third required lipid lowering drugs, 19% were current smokers more than 25% had poor glycaemic control with a HbA1c>7.5% [87]. In an Italian cohort of 2113 patients with type 2 diabetes only 44% had a reasonable BP control, only 51% achieved appropriate HbA1c levels and 4% did not obtain any of six recommended therapeutic goals [88]. According to a Swedish registry study of patients with acute myocardial infarction those with concomitant diabetes were less often treated with thrombolysis (31% vs. 41%), heparins (37% vs. 43%), intravenous beta-blockers (29% vs. 33%) and were less likely to undergo an acute revascularisation (4% vs. 5%) than their non-diabetic counterparts [89]. Following myocardial infarction the diabetic patients treated in a general hospital in UK were less often on aspirin (75% vs. 90%) and beta-blockers (39% vs. 61%) and were less likely to attend physiotherapy sessions (27% vs. 59%) than non-diabetic patients [71]. These data should be perceived as a call for immediate action to assure an adequate implementation of the existing guidelines.
Concluding remarks
The substantial lack of well established and appropriately tested treatment approaches for the management of diabetic patients with coronary artery disease may contribute to confusion while making clinical decisions and may limit the use of available, potentially beneficial treatment with the risk to worsen an already unfavourable prognosis. Factors related to cardiovascular events and to the onset of type 2 diabetes seem to be interrelated. If any actions are to improve the cardiovascular outcomes and prognosis of patients with diabetes mellitus, it seems that preventive measures ought to be applied already during the prediabetic stage. Combined efforts of all professions involved in cardiovascular and diabetic care are needed to identify patients at particular risk. The initiation of intense medical treatment accompanied by preventive programs aiming at effective modification of risk factors are mandatory. There is also an urgent need for formulation of guidelines updated to the most recent scientific evidence concerning treatment strategies with the capacity to improve the short- and long-term outcome of patients with insulin resistance, IGT and overt diabetes.
Footnotes
Acknowledgements
This paper was supported by grants from the Swedish Heart and Lung Foundation and from the European Society of Cardiology.