KP is a 56-year-old school teacher. He has had diabetes for 21 years and has his blood sugar under control. At his most recent check-up, his doctor commended the fact that he did not have a single diabetes-related complication, despite nearly two decades of diabetes.

A is a 57-year-old businessman. He was detected with diabetes at the age of 39. At his latest check up, his doctor had some bad news; although his blood sugars were presently under control, he already has evidence of kidney and eye complications.


Here are two individuals of the same age and who have had diabetes for roughly the same length of time. Then why is it that only one has developed diabetic complications? To find the answer, we need to go deeper into their stories. KP, it transpires, was found to have diabetes during a routine master health check up. He has meticulously followed the advice given to him. He has not missed his medication even for a single day. As a result, his blood sugar values have always been at or below the target values.

A, on the other hand, was diagnosed when his wife noticed he was losing weight and passing urine frequently in the night. His blood sugars were very high then and remained so for quite some time, because he could not spare time to exercise or follow the recommended diet regimen. Since he travelled frequently, he often missed his medication for days. Finally, around two years ago, he suffered a heart attack and had to undergo bypass surgery. He realised the seriousness of the problem and has been following doctor's advice ever since.

Diabetes is the leading cause of kidney failure in the world, and is also a major cause of heart attacks, blindness and foot amputations. A number of studies over the last 20 years have shown that good control of diabetes can prevent or substantially delay the development of many of these complications.

One such study was conducted in the United Kingdom over 20 years (1977-1997). The investigators divided patients with Type 2 (non-insulin dependent) diabetes into two groups. One group was treated intensively to achieve tight control of blood sugar, while the other group was treated less intensively. After a decade, it was found that the patients given intensive treatment had a much lower risk of developing diabetes complications than those in the second group. These findings were published in 1998.

Several years later both groups were studied again. The results were startling. The individuals in the tight control group continued to have a lower risk of diabetes complications (compared to the other group), even though their control had subsequently become worse! This shows that good control of diabetes early in the course of the disease has far-reaching benefits throughout life. This has been termed the “legacy effect”. That is, by controlling diabetes as soon as it is detected, one bequeaths a legacy of good control to the cells and tissues, which will stand them in good stead throughout life.

Positive and negative effect

In what way does the “legacy effect” apply to the two patients mentioned above? KP benefited from a “positive legacy” since he kept his diabetes under control from day one. He therefore does not have any complications and is unlikely to develop any in the future, provided he continues the same lifestyle pattern. On the other hand, A has not treated his body well. He has allowed a “negative legacy” i.e. an increased susceptibility to diabetic complications by neglecting his diabetes. Therefore he has developed all the complications of diabetes. Though he has controlled his blood sugars now, it is likely to be a case of “too little, too late” as the subsequent development of eye and kidney complications shows.

To benefit from a “positive legacy” effect, one needs to detect diabetes early. If diabetes is detected several years after it has set in, one loses the chance to influence its natural history.

Often, patients are found to have complications of diabetes even at the time of first diagnosis. This means that the patient has had diabetes for at least five years, without his knowledge. In such a case, there is no scope to build a positive legacy effect; all that can be done is damage limitation. The risk of diabetes can be assessed using simple tools such as the Indian Diabetes Risk Score.

Diabetes is a progressive disease. It is easiest to control diabetes in the first few years. Unfortunately, many patients do not take the disease seriously, as they do not have any symptoms. This prevents them from attaining good control of diabetes at a time when it is easiest to achieve such control.

Diabetes-related complications can be severe, often life-threatening and mostly incurable. Remember; the best time to detect and control diabetes is NOW!

The authors are Chennai-based diabetologists. Website:


Sunday MagazineJune 28, 2012