Dr Aidin Rawshani

Life expectancy and survival in type 1 diabetes


People with type 1 diabetes have less life expectancy than 17 years: but what does that mean to you?

Today, a research group from the National Diabetes Register and the University of Gothenburg is publishing a new study in The Lancet. The study is a world first for anyone with type 1 diabetes. The results are of great importance for the care and for individuals living with type 1 diabetes. The aim of the study was to investigate the longevity and risk of cardiovascular diseases among people with type 1 diabetes. It was examined how age at the time of diagnosis (i.e. how old the person was when diagnosed with type 1 diabetes) affected the following:

  • Life expectancy.
  • The risk of heart attack, stroke, heart failure and other complications

Until today, we have not known what life expectancy looks like for Swedes with type 1 diabetes. Nor have we known if it matters when in life they got diabetes. The results of the study have attracted a lot of attention in the media and unfortunately there were some misunderstandings that caused concern among patients and relatives. Here we discuss the background of the study, the results and, in addition, we sort out the misunderstandings.

Why was this study important?

All knowledge about type 1 diabetes is important. The more we know about type 1 diabetes, the better the care will be. If we can find differences in life expectancy and risk of complications in different groups, we can identify groups that need more care. We can then put in measures and treatments earlier for a prevent or postpone complications.

Further, it is fundamental to be able to answer the question of life expectancy. People with type 1 diabetes, as well as relatives, understand that type 1 diabetes is a serious disease. Often they have been informed that the risk of cardiovascular disease and premature death is increased if you have type 1 diabetes, but until today we have not been able to answer the question of life expectancy in Sweden.

Which groups were examined in the study?

The study compared 5 groups, based on when in life they received type 1 diabetes (age at diagnosis). The groups are as follows:

  • 0 to 10 years
  • 11 to 15 year
  • 16 to 20 years
  • 21 to 25 year
  • 26 to 30 years

To investigate the risk of diabetes, each person was compared to type 1 diabetes with 5 controls from the population (people without diabetes). The control persons would be the same age, same sex and live in the same county.

What did the study show?

Survival and risk of cardiovascular disease in type 1 diabetes depend heavily on when in life you get the disease. The earlier in life one develops type 1 diabetes, the more dangerous the disease and, accordingly, the need for medical intervention is greater. The results are of great clinical significance as it can be indicative when deciding on treatment, as well as caring for people with type 1 diabetes.

Specific results regarding life expectancy

  • Girls who had type 1 diabetes before the age of 10 lost 17.7 years of life.
  • Boys who had type 1 diabetes before the age of 10 lost 14.4 years of life.
  • Total (boys and girls) people lost 16 years of life
  • If you got type 1 diabetes before the age of 10 years. lost man 9.7 years of life.

Specific results regarding the risk of complications

  • Individuals with type 1 diabetes before the age of 10 had an average of 30 times increased risk of coronary heart disease and heart attack. Most pronounced was the risk for women: the onset before the age of 10 was fraught with 60 times increased risk of coronary heart disease and 90 times increased risk of a heart attack.
  • All risks were lower for people who received type 1 diabetes later in life. Women diagnosed with type 1 diabetes at 26—30 years of age had a 12-fold increased risk of coronary heart disease and a 14-fold increased risk of a heart attack.
  • The risk of death from cardiovascular disease was increased 4-fold for those diagnosed at the age of 26—30 years and about 11-fold increased for those who were diagnosed with diabetes mellitus. was diagnosed before the age of 10 years.
  • Developing type 1 diabetes before the age of 10 entailed almost 13 times increased risk of heart failure, without any differences between men and women.

But can this really be true? 18 years lost?

One must be very careful when interpreting these results and there is no reason to be frightened. The results mentioned in the study apply to the whole group with type 1 diabetes, so the results cannot be applied to you as an individual. The explanation is as follows:

  • In this study, all Swedes with type 1 diabetes have been studied. When you study “all”, you study a group with great variation regarding the disease. Many who were involved in the study had their diabetes several decades ago, i.e. during a time when the care was significantly worse than it is today. Today we have better insulins, more technical aids, better blood sugar, more knowledge about blood pressure and blood lipids etc. This means that those who have had diabetes in recent years (even the last few decades) can be guaranteed to look forward to a much better prognosis!
  • It gets better and better every day. We know from previous Swedish research that mortality and risk of cardiovascular disease have fallen by 30% in the last 15 years! This means that we are making tremendous progress and you with type 1 diabetes can certainly look forward to an even better prognosis, an even better quality of life and even lower risk of complications.
  • Although the risks were much higher for people with type 1 diabetes compared to controls, there were still a few diabetics who actually suffered complications or death. The high risk compared to controls is explained by the very low risk of these complications.
  • So, even if the risk is high compared to control people, the risk for you as a diabetic is still low! The importance of blood glucose control is not investigated in the study. The study shows that the youngest individuals had HbA1c of about 70 mmol/mol, which is high and currently most have much lower HbA1c than 70 mmol/mol.
  • We know (with certainty) that lower blood sugar means a lower risk of complications. So you can continue to strive for low blood sugar and know confidently that it lowers your risks.

However, the above should not embellish reality. The results of the study are still valid when we talk about the whole group that has type 1 diabetes in Sweden. So there are people today who live with type 1 diabetes and who will, therefore, lose 18 years of life. These results are extremely important to get out to the public and to decision-makers who guide care and resources to care.

What can we and you do to improve the prognosis?

The prognosis and quality of life of people with type 1 diabetes improve every day. In the last 15 years, morbidity and mortality have fallen by 30%, and this is a sensational figure that we should welcome. Swedish diabetes care is at the international forefront and we know what to do to improve prognosis, reduce the risk of complications and improve the quality of life for you with type 1 diabetes. The goal is that you who have type 1 diabetes should be able to live a normal life and enjoy like everyone else.

The main measures to achieve this goal are as follows:

  • Intensive blood sugar control — the aim to keep the blood sugar as low as possible — is the cornerstone of treatment. Technical advances in glucose measurement and insulin therapy have improved glycaemic control and more people with type 1 diabetes can achieve intense glycaemic control. You can contact your healthcare provider at any time to discuss possibilities and methods to improve your blood sugar.
  • More people with type 1 diabetes need to be provided with technical aids that facilitate blood sugar control. In particular, insulin pumps and continuous blood glucose meters.
  • Since cardiovascular disease is the leading cause of morbidity and mortality among people with type 1 diabetes, treatment with blood pressure medications and cholesterol lowering agents (statins) has become more common, but even more people need to get treatment. We know today, thanks to the National Diabetes Register, that very many people lack treatment with blood-lowering drugs, as well as antihypertensive drugs. This is not acceptable; every nurse and doctor must ensure that patients have received these medicines if warranted. As a patient, you may ask whether you are a candidate for this type of cardioprotective drug.
  • Care providers must consider starting cardioprotective treatment earlier in life, especially if the person has experienced type 1 diabetes during childhood.

The study is an awakening

The new study offers an awakening. Type 1 diabetes is a serious disease and most at risk are those who debut in childhood. Carers should consider and adapt care according to age of debut, in particular, aspects related to treatment decisions. Early-onset involves several times higher risk of death and cardiovascular disease and therefore these individuals should be subject to even more intensive risk factor control. Despite this, it is certainly the case that the high risks noted in the study are largely explained by people who had diabetes many years ago, when the care was not as good as it is today. Those who have had diabetes in recent years can certainly look forward to a significantly better prognosis than the one presented in the study (which therefore applies to the whole group).

It gets better and better

It should also be emphasized that the prognosis for type 1 diabetes has improved enormously in recent decades. The annual report from the National Diabetes Register shows that risk factor control is improving every year and the use of modern methods of glucose measurement and insulin pumps is steadily increasing. This means that people living with type 1 diabetes today, as well as those who will develop the disease in the future, can forward to constant improvement in the quality of life and prognosis.

Hopefully, the study can trigger clinics and decision-makers to start cardioprotective treatment earlier and increase the use of technical aids that improve blood sugar.

The importance of the National Diabetes Register

The National Diabetes Register (NDR) is a national quality register that has worked continuously over the past 20 years to ensure the quality of Swedish diabetes care. NDR is invaluable for care and you can read more about NDR, as well as see today’s press release.

Final words

Swedish diabetes care is world famous for its quality and results, which means that you are in good hands. We have come very far in the treatment of type 1 diabetes, but there is still a lot of work to be done. The prognosis is getting better every day and there is no cause for concern because of this study; on the contrary, this study will eventually lead to even better lives for those living with type 1 diabetes.

Read the study

Rawshani A, Eliasson B, Sattar N, Franzén S, Rawshani A, Godbear Dottir S, et al. Excess mortality and cardiovascular disease in young adults with type 1 diabetes in relation to age at onset: a nationwide, register-based cohort study. The Lancet.

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