The heart of diabetics often suffers in silence and this results in an elevation of “troponin T” in the blood, a marker of lack of oxygen in the heart muscle. However, this rise in troponin would be more frequent in the event of episodes of severe hypoglycaemia.
Certain anti-diabetic drugs can cause low blood sugar, which could lead to heart damage, according to a new study. To reach this conclusion, scientists sought to determine whether hypoglycemia was associated with higher levels of troponin T in the blood, a marker of lack of oxygen supply (ischemia) in the heart muscle (myocardium).
Researchers first randomly selected patients with diabetes type 2 and coronary artery disease*, then closely monitored their blood sugar and troponin T levels for a year. Results: of 1,984 patients, “severe hypoglycaemia” was associated with an increase in troponin T levels, 6% higher than the average, and “proven hypoglycaemia” was also associated with an increase in troponin T levels , 4% higher than average. According to these markers, diabetics would therefore have a greater risk of cardiac suffering (ischemia) than the average population.
Silent myocardial ischemia
Myocardial ischemia is a disorder of heart function caused by insufficient supply of oxygenated blood to the muscular tissues of the heart. Decreased supply of oxygenated blood may be due to narrowing of the coronary arteries (coronary atherosclerosis), obstruction of the artery by a thrombus (coronary thrombosis), or less commonly to diffuse narrowing of arterioles and other small vessels in the heart. Abrupt interruption of the blood supply to the heart muscle (the myocardium) can result in a myocardial infarction.
“Furthermore, the myocardial ischemia of the diabetic, complex and of insidious evolution, tends to present itself in a silent form (“silent myocardial ischemia”), thus delaying the diagnosis and the specific treatment, thus worsening the prognosis of the patients” , say the experts of the General Diabetes Reviews. “Thus, after age 60, the relative risk of subsequent occurrence of a major cardiac event is 3 times higher in diabetics with silent myocardial ischemia than in diabetics without silent myocardial ischemia”, they add.
550 million diabetic patients by 2025
What we do not yet know is whether the more frequent hypoglycemia is linked to a weakened ground which is accompanied by coronary insufficiency or whether hypoglycemia is responsible for coronary insufficiency. This study provides one more argument in favor of the deleterious nature of hypoglycaemia on cardiovascular risk.
In addition to cardiac complications, diabetes increases the risk of amputation by eight (5 to 10% of diabetics have or will have their toe, foot or leg amputated) and by nine the risk of dialysis for end-stage renal failure (25% of cases of diseases destroying the kidneys are attributable to it). It is also the leading cause of blindness in adults.
One in ten French people has diabetes, and 500 to 800,000 diabetics are unaware that they are sick. The current global forecasts are far more worrying as they announce 550 million diabetic patients for 2025 and 642 for 2040.
*the most common form of heart disease.
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