Diabetes Mellitus Made Easy

We know that diabetes mellitus is a chronic metabolic disease closely associated with high blood sugar level, but how do we confirm diagnosis apart from observing an array of classical presenting symptoms?


PS: normal blood glucose level of human is about 5.6mmol/L or 80-100mg/dl.

As you can see, there are 4 methods to diagnose a person with diabetes mellitus.

  • The subject should be refrained from any food intake for at least 8 hours. The test of blood sugar level at this period of time is called fasting blood glucose. Value above 126mg/dl or 7.0mmol/L is diagnostic of DM.
  • The subject should consume 75g of glucose water and have his/her blood sugar level tested after 2 hours, also known as impaired glucose tolerance test. Ideally, this test should only be done if the person’s fasting blood glucose level falls between norm and diabetic value.

(Why 2 hours? Well this is the time frame when our blood glucose level starts to fall back to its normal value after sugar consumption. So if blood sugar value remains high at this time, >200mg/dl or 11.1mmol/L in this context, it is diagnostic of DM)

  • Random glucose means the test of blood sugar level at any time when a person isn’t fasting nor eating.

(Therefore blood sugar level at this period of time should remain within the normal range, otherwise it would be indicative of DM)

What about HaemoglobinA1C (H1Ac)?

This is a rough estimation of the amount of sugar a person consume for the past 3 months. Its normal value is 5.7% and any value above 6.5% would be indicative of DM.

PS: Some non-compliant diabetic patients who allows themselves to be indulged in sugary food are smart enough to not consume any of it right before medical check-up in the hope of getting by. However, a H1Ac test would reveal the truth behind.

In case you are wondering, what about those test values that fall in between normal and diabetic level?

In this scenario, we would designate these people as pre-diabetic or impaired glucose tolerance (IGT). Technically, people who fall under this category are not diabetic BUT is prone to have diabetes in the future. In fact, studies have shown that IGT patients will eventually develop DM if there is no changes in their lifestyle.

Diabetes Mellitus Classification

On physiological point of view, diabetes mellitus occurs when our blood glucose fails to be delivered into the cell for normal functioning causing glucose level in the bloodstream remain high at all time. This may occur:

  • When the pancreas does not synthesize or synthesize at insulin at a very low level
  • When the pancreas DOES synthesize insulin but the surface of cells is resistant to insulin action

*Insulin is the hormone that facilitates glucose absorption from our bloodstream into cells for utility. In other words, insulin is what causes the decrease in blood glucose level after meal.

Based on these two mechanisms, the scientists classify diabetes mellitus into type I (also known as insulin dependent) and type II (insulin independent) respectively. Interestingly, type I diabetes affects mostly children or adolescents while type II diabetes associated with older adults and most of these adults happen to be obese. Therefore obese patients are always advised to have their blood glucose checked because apart from cardiovascular heart diseases and arterial hypertension, they also fall under the high risk group of people that have a tendency to develop DM type II. This is due to the fact that the cells of obese people have a lower sensitivity toward insulin.


Signs and symptoms   

The combination of below 3 symptoms that are highly suggestive of diabetes:

  • Polyuria
  • Polyphagia & Polydipsia
  • Loss of weight

*Polyuria- frequent urination, polyphagia- increased appetite, polydipsia- increased thirst

Of course, it is not uncommon to hear vague complaints such as headache, difficulty in concentration, lethargic, blurred vision etc. All these symptoms may aid in confirming diagnosis however they may also appear in other spectrum of medical conditions. In this context, these symptoms are simply the clinical manifestation of the inability of our body to utilize blood glucose.

One point worth mentioning is that, some patients might present with a “fruity” breath odor. This phenomenon occurs in a process known as diabetic ketoacidosis when the liver starts converting fatty acids from the body cells to ketones as the main source for energy consumption.

As trivial as it may sound from the aforementioned 3 red flags, there are actually some acute complications such as non-ketotic hyperosmolar syndrome that may occur if diabetes is not well controlled.  On the other hand, prolonged high blood glucose level will eventually lead to systemic complications such as diabetic food ulcer owing to poor wound healing (diabetic neuropathy), chronic kidney disease which eventually will lead to kidney failure (diabetic nephropathy), complete loss of vision (diabetic retinopathy) etc.



Treatment method may vary depending on the type of diabetes and the severity of the disease. However, lifestyle changes are imperative to prevent disease progression beside pharmacological intervention. Diabetic patients are advised to drink plenty of water every day to prevent dehydration, but it must be avoided in patients with co-morbidities such as chronic heart failure. Besides that, patients must also remember to engage in moderate intensity exercise to lower blood sugar level. In fact, studies have shown that regular physical activity increases the sensitivity of cell membrane to insulin.

CAUTION: Patients with diabetes type I should avoid physical activity immediately after taking insulin shot as this might lead to hypoglycemic coma!

Next, it is crucial for diabetic patients to change their diet habit. Processed food that contains high refined sugar and carbohydrates like cookies,brownies and white bread should be avoided at all cost. Instead, choose the source of carbohyrates which has low glycemic index (food that triggers a stable rise in insulin) like whole-grains, old fashioned oats. Food that is high in saturated fat like butter should be kept at a minimum level to counter obesity and at the same time decrease the likelihood of development of cardiovascular disease. Replace food that is high in saturated fat with those high in polysaturated/unsaturated fats like extra virgin olive oil, omega-3 fish oil or almonds. There is no restriction in protein intake except those people with chronic kidney disease. As a general rule of thumb, diabetic patients’ diet should contain more vegetables as they provide enormous amount of vitamins, fibers and other nutritional benefits. Consumption of high fructose fruits like banana, honeydew or mango should be limited in diabetic patients as these fruits contain high amount of sugar which would cause a sudden spike of insulin, something you do not want to see happening in diabetic patients.

Pharmacological intervention has to be incorporated to help controlling blood glucose level. All type I and some of the type II diabetic patients are given insulin treatment as their pancreas does not synthetize the amount of insulin required to bring blood glucose level back to normal level after meal. There are different types of insulin shots that vary in terms of their onset, peak time and the length of action. The conventional Rapid-acting insulin analogue taken at the start of the meal and will last for about 2.5 hours. There is also medium and long acting insulin analogue that ensure a steady supply of insulin and well controlled blood glucose level throughout the day and they are usually administered once daily. These insulin analogues are usually taken in combination with the short acting ones to provide optimal results. The table below summarizes the main types of insulin preparations:


Compliant type II diabetic patients’ blood glucose level may drop significantly if they are  committed to their lifestyle and diet changes. However, diabetic medications would have to be introduced if the former is not effective in controlling blood glucose.

In such case, diabetic medications used conventionally include:

  1. Sulfonylurea
  2. Metformin
  3. Thiazolidinediones

There are other newer drugs that have just been released into the market in recent few years such as SGLT-2 Inhibitors, DPP-4 Inhibitors and GLP-1 Agonists. These drugs have proven to be more effective and have lesser side effects compared to the conventional ones, but they are more costly and hence less economic for long term usage.










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