Why diabetics face the risk of having cardiovascular disease | Lifestyle.INQ

OCTOBER 27, 2022

Although as cardiologists, we’re supposed to attend only to patients with heart ailments and those with problems in the arteries, we also get to see a lot of diabetics in our clinics.


First reason is that diabetes may coexist with other risk factors for heart disease, such as obesity, high blood pressure (BP) and cholesterol problems, specifically high triglycerides and a low level of the good type of cholesterol called high density lipoprotein (HDL).


For Filipinos and Asians, a low HDL is the most frequent type of cholesterol problem occurring in about 70 percent of the adult population. Checking only for the total cholesterol level in your blood is not enough. We have to request for the subtypes of cholesterol, HDL and the bad type, called low density lipoprotein (LDL).


Even if one has normal cholesterol, if the HDL is also low, he or she is at risk to develop heart attack, stroke and other cardiovascular problems. When we say cardiovascular, we refer to the heart, brain and arteries throughout the body.


Diabetes, obesity, low HDL, high triglycerides and high BP may come as a package of medical problems, and when at least three of them are present, the person is said to have metabolic syndrome (MS). This carries an increased risk for cardiovascular complications, three to four times that of individuals who don’t have the syndrome.


Overweight and obesity are usually determined by computing for the body mass index (BMI) based on one’s height and weight. In Caucasians, the normal BMI is 25 or less. A BMI more than 25 is considered overweight, and more than 30 is obese.


There is a peculiarity among Filipinos and orientals, though. Even at supposedly normal BMIs of 23 to 25, there can be hidden fatness observed, particularly in the abdomen (visceral obesity). They’re described as “lean but obese.”


Strong family history


Some Filipinos may look trim and lean, but they may have diabetes plus the other components of MS. So, if one has a strong family history of diabetes or high BP, it’s best to see one’s family physician and rule out possible MS.


The second reason we see a lot of diabetic patients is that the major cause of death of diabetics is cardiovascular, due to complications in the heart and arteries. Hence, we have to be proactive in managing their cardiovascular condition. A diabetic who has never had a heart attack carries the same high risk of having a heart attack as a nondiabetic who already had a previous heart attack. Hence, some experts label diabetes as a coronary heart disease equivalent in terms of risk.


Some diabetic patients ask us why we prescribe them statins, which is a cholesterol-lowering drug, even if their blood cholesterol levels are not high, or a class of antihypertensive drugs called RAS blockers even if they’re not hypertensive. It’s because these drugs have been shown to have beneficial effects on diabetics and other high-risk patients, even in the absence of their primary indications, i.e., high cholesterol and high BP.


It is ironic, though, that aggressive antidiabetic treatment to lower blood sugar to theoretically normal levels could possibly do more harm than good, particularly in the elderly and in those with weak hearts and failing kidneys (renally impaired). Several landmark studies have already shown this. In fact, some categories of diabetics ironically die earlier or suffer more heart attacks and strokes if their high blood sugar is aggressively lowered, compared to those with less stringent control of their diabetes.


One likely reason for this is that aggressive control of diabetes can lead to more hypoglycemic episodes, and the excessive lowering of the blood sugar can make the heart more irritable, causing arrhythmia (abnormal heartbeat), which may lead to sudden cardiac arrest. So, among elderly diabetics and those with impaired hearts and kidneys, it’s better to maintain slightly higher blood sugar levels.


Aside from random blood tests which patients themselves can do at home with finger-prick tests, the level of blood sugar control may also be assessed periodically (usually every three to six months) by doing a test called glycosylated hemoglobin or HbA1c.


When cardiologists see a diabetic patient, they intuitively see a red flag for potential cardiovascular complications, and they have to maintain a “sweet spot” in the various treatment regimens they prescribe. Under- or over-treatment or anything outside the sweet spot can ironically do more harm than good in the diabetic patient. The cardinal rule of medicine is “Primum non nocere” (First do no harm).

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