Cardiovascular risk in diabetes

The cardiovascular risk in diabetes is determined by some comorbidities. Renal dysfunction and micro- and macrovascular events are common. Should diabetes patients be screened for cardiovascular risks?

Implementation of guideline recommendations is essential

The cardiovascular risk in patients with diabetes is determined by a number of comorbidities. Renal dysfunction and micro- and macrovascular events are particularly common. But should all people with diabetes be screened for cardiovascular risks?

The case

A 71-year-old woman attends her medical appointment. She suffers from hypertension, hyperlipidemia, and insulin-dependent diabetes mellitus. The BMI is 29 kg/m2. In addition, the patient suffers from a severe occlusive peripheral arterial disease, repeated attacks of angina pectoris, and suffered a mild stroke years ago.

Furthermore, the limited kidney function is striking with creatinine = 1.71 mg/dl, eGFR = 29 ml/min/1.73 m2 and an albuminuria of 150 mg/24 h. Blood glucose is 100 mg/dl and an HbA1C of 8.6%. Single-photon emission computed tomography (SPECT) of the heart also revealed necrotic and anterolateral ischemia areas. 

Due to her numerous comorbidities, the patient is taking up to nine different medications, so she belongs to the group of "fragile" patients with polymedication.

Due to the ischemia in combination with the reduced renal function, the patient was included in the control arm of the ISCHEMIA-CKD study. However, after five months, the symptoms reappeared. Angiography showed coronary impairment, which is why surgical revascularization was suggested. Thus, the patient received coronary artery bypass grafting (CABG) surgery as it was shown to have a lower 4-year mortality rate compared to percutaneous coronary interventions (PCIs) (16.4% versus 58%). After revascularization, kidney function also improved somewhat initially.

Should I screen for macrovascular events?

A case like the 71-year-old diabetic presented is not easy to assess because of the high comorbidity burden and the resulting cardiovascular risk. But should such patients be screened for micro- and macrovascular disorders at regular intervals? For the time being, yes, because this allows risk to be identified much earlier. But does this kind of finding ultimately change the therapy? What do the current guidelines suggest in such cases?

Especially when the patients show no or very few symptoms, there is little data on any further clinical procedure. Moreover, due to the circumstances, multidisciplinary teams are a prerequisite for the proper monitoring of patients. However, diabetes patients should always be tested regularly for microalbuminuria in order to detect possible changes in kidney function over time. In addition, a resting ECG is recommended in cases of additional hypertension or suspected cardiovascular disease (IC), for example, to detect silent heart attacks or arrhythmias. Further diagnostic methods, such as arterial ultrasound or CT, achieve much weaker recommendation levels of IIa or IIb due to the lack of a database.

Furthermore, the screening for asymptomatic cardiovascular diseases in asymptomatic patients with diabetes mellitus is discussed very controversially. For example, the American Diabetes Association does not recommend general coronary heart disease screening for patients with diabetes (A). However, such screening could be offered in cases of atypical cardiac symptoms, signs of cardiovascular disease, stroke, ECG abnormalities, or ischaemic attacks (E).

The European Society of Cardiology (ESC) also defines three risk groups for diabetics with regard to cardiovascular risks:

  1. Moderate risk in young diabetics (<50 years of T2DM) and a duration of illness of < 10 years and without other risk factors.
  2. High risk in diabetics with a duration of illness of > 10 years and existing cofactors.
  3. Very high risk in patients with diabetes mellitus and a history of more than 20 years as well as cardiovascular diseases, kidney dysfunction (eGFR < 30 ml/min/1.73 m2), or other diabetic secondary diseases and comorbidities.

It is also important to note that the risk of cardiovascular events increases with the degree of renal dysfunction.

Implementation of guideline recommendations

There is still too little data that would show that every diabetic with kidney function impairment needs imaging to show cardiovascular disease. Based on the guidelines currently available, we should rather think of an individualized setting, in which the primary focus is no longer on glucoreduction, but rather a greater awareness of events. The aim here is to slow down the decline in kidney function.

The new SGLT2 inhibitors can be helpful because studies have shown that they also protect diabetics from an increased risk of heart failure and protect kidney function. This means that these new drugs not only offer a means of glycemic control in diabetes but also help to prevent heart failure and slow down the development of kidney dysfunction.

Guidelines in Practice - My Patient with Diabetes and Chronic Kidney Disease - Should I Be Looking for Macrovascular Disease? ESC 2020 (virtual)