Summary | The cardiovascular challenge for primary care in diabetes
Prof. Hobbs started his presentation by asking whether vascular disease prevention is especially important in diabetes patients. In general, preventing CVD is one of the most important challenges faced by healthcare. Data from the Global Burden of Disease project showed that ischemic heart disease (IHD) and stroke, the main clinical manifestations of vascular disease, are the most important causes of premature death and disability (1). Therefore, it is not surprising that risk factors for vascular disease are the most important issues for healthcare systems. Important to realize is that the high impact of vascular disease is similar world-wide; it is a global problem.
The significance of diabetes in relation to vascular risk can be explained, among other reasons, by the high prevalence of diabetes. Diabetes affects ~8% of the world population, resulting in high absolute patient numbers (2). The risk of vascular disease is almost two-fold higher in diabetes patients compared to individuals without diabetes (3). Vascular disease is not a direct consequence of diabetes. It takes about a decade after diagnosis of diabetes before risk of coronary heart disease (CHD) reaches the CHD equivalent threshold (4). Needless to say, vascular disease is an important cause of death in diabetes patients and it results in significant loss of life; up to seven years of life are lost in an individual at the age of 50 years with diabetes, but no history of vascular disease, with an even greater impact in women (5).
Beyond glucose control, an important factor via which vascular risk can be modified is smoking. Obviously, it is very important for patients to prevent or stop smoking. On average, an individual will lose ten years of life by smoking, but the earlier one quits smoking, the more years lost can be regained. Worthwhile to notice is that it is never too late to stop; even if an individual stops smoking at 50 years, the number of years lost is reduced (6).
Blood pressure (BP) is another important risk factor of vascular disease and it is a very prevalent one. Trial results have shown that BP control results in large reduction of stroke, heart failure (HF) and myocardial infarction (MI) (7, 8). In general, effectiveness of BP control is similar in patients with diabetes and in individuals without diabetes. Interestingly, the effect of BP on some clinical outcomes, for example stroke, is even more favorable in patients with diabetes (9).
Control of LDL-c levels by statins is an another target of reducing vascular disease, which is very effective with a 16% reduction in CV events for each mmol/L reduction in LDL-c in patients with a history of CVD or in primary prevention (10), irrespective of diabetes status (11). Therefore, statin therapy is an important and effective strategy to reduce CV events in patients with diabetes, even though use of statins results in an increased risk of dysglycemia of ~9% (12). It is important to realize that patients who, end up developing diabetes as a consequence of statin initiation, still benefit from the same vascular risk reduction with statins as individuals without diabetes.
Adherence to therapy is an important factor that determines vascular risk, as patients who are non-adherent have a two-fold increased risk of vascular events compared to patients who adhere to therapy. Important to realize is that, even though patients adhere to their statin therapy, they may have a large residual risk (13). Therefore, there is a need for additional treatment to reduce vascular risk in patients with diabetes.
Glycemic control to reduce vascular risk has yielded much more disappointing effects. Until the appearance of sodium-glucose co-transporter 2 (SGLT2) inhibitors and GLP-1RAs, no large CV benefit had been observed with anti-diabetic agents. Intensive strategies with traditional glucose-lowering therapies have not shown benefit on clinical endpoints including mortality and macrovascular events (14). Lifestyle improvement has been demonstrated to prevent diabetes, but not to reduce vascular risk once diabetes has developed (15). The onset of diabetes could be delayed in ~50% of cases by a variety of lifestyle interventions (16) and is therefore an important strategy in patients with increased risk of diabetes.
Looking at the current trends in relation to primary care, the most important one is the increase in obesity. Data have shown that more than half of adults in the United Kingdom are either clinically overweight or obese. The obesity trend has increased over the last 20 years, culminating into nearly 25% of the population being obese. A close association between BMI and subsequent onset of diabetes was observed in the Nurses’ Health Study with a 15 year follow-up (17). At a BMI >30 kg/m², the rate of diabetes incidents is increased, and this is observed world-wide. This was clearly demonstrated in the United States, where elevated rates of obesity were followed by a similar increase in the rate of diabetes over time. Obesity is a social as well as a medical problem and there are many interventions that need to be considered at a system level to stop the increase in weight in the population and reduce the impact on health.
This is a summary of the presentation given by prof. Hobbs, during the PACE symposium entitled 'Preventing Cardiovascular Disease in Patients with T2DM – How to apply novel outcome data with GLP-1RA to clinical practice', held during EuroPrevent in Ljubljana, Slovenia, on May 3, 2018.