📘 Type 1 diabetes mortality: causes and life expectancy

Yes, type 1 diabetes increases mortality risk compared to the general population. Patients with type 1 diabetes have a risk of death up to three times higher compared to people without diabetes, varying significantly depending on age, disease duration and quality of glycaemic control. A Finnish study published in 2024 reported an 84% higher risk of death compared to the general population. The excess risk of death from T1DM is highest in the 30-49 age group [1].

The main factors contributing to this increased risk of death are cardiovascular disease, chronic kidney disease, diabetic ketoacidosis and severe hypoglycemia. The good news is that mortality has decreased significantly in recent decades due to improved treatment, continuous glucose monitoring and management of cardiovascular risk factors [2].

Life expectancy means how many years you have left to live from now. In type 1 diabetes, it varies considerably depending on the country, access to modern treatment and quality of medical care. The estimated life expectancy for a 10-year-old child newly diagnosed with T1DM varies enormously, ranging between 6 and 66 additional years, depending on the country of residence [3]. In high-income countries, where access to insulin, monitoring and therapeutic education is good, life expectancy approaches that of the general population [4].

Nevertheless, globally, it is estimated that approximately one in 15 newly diagnosed T1DM patients will die at the time of onset due to delayed access to treatment, especially in low- and middle-income countries [3]. The determining factor for improving this situation is equal access to modern treatment of the disease.

The most important predictors of mortality in type 1 diabetes are chronic kidney disease (especially end-stage), cardiovascular disease, mental and behavioural disorders, diabetic foot, elevated LDL cholesterol and HbA1c values above 8% (64 mmol/mol) [1, 5].

Additionally, untreated arterial hypertension, smoking and sedentary lifestyle contribute to the increased mortality risk. Arterial stiffness is also an independent predictor of mortality in type 1 diabetes [6]. It is essential that each risk factor is identified and treated early, as their effect is cumulative. The combination of poor glycaemic control and chronic kidney disease or cardiovascular disease multiplies the risk.

Glycated haemoglobin (HbA1c) plays an essential role in reducing long-term mortality in type 1 diabetes. A period of intensive glycaemic control produces benefits that are maintained for decades, even if that level of control subsequently deteriorates. This phenomenon is called "metabolic memory" [7]. A lower HbA1c value in the first 5-10 years after onset, followed by a relaxation of metabolic control, confers a significantly lower risk of cardiovascular and renal complications and death, even 30 years into the future.

An HbA1c above 8% (64 mmol/mol) is associated with a 27% increase in mortality risk [1]. The ADA guideline recommends an HbA1c target below 7% (53 mmol/mol) for most adults with type 1 diabetes, outside of pregnancy [8]. For healthy but older adults, a target below 7.0-7.5% (53-58 mmol/mol) is reasonable to reduce complications and mortality. Importantly, HbA1c reduction must be achieved without increasing the frequency of severe hypoglycemia, which is why the use of continuous glucose monitoring systems and smart insulin pumps is very important.

Obesity is an increasingly common problem in people with type 1 diabetes and has a negative impact on mortality. Obesity in type 1 diabetes has both classic causes and factors related to insulin treatment. The association of obesity with type 1 diabetes is sometimes called "double diabetes" because it combines the insulin deficiency specific to type 1 with the insulin resistance characteristic of type 2 [9].

Obesity worsens glycaemic control by increasing insulin resistance, which increases insulin requirements and consequently the risk of hypoglycemia. Additionally, obesity accelerates the onset and progression of cardiovascular complications, which are the leading cause of death in type 1 diabetes [10].

The main causes of death in people with type 1 diabetes are cardiovascular disease (myocardial infarction, stroke, heart failure), chronic kidney disease, diabetic ketoacidosis, severe hypoglycemia and cancer. Cardiovascular disease is the leading cause of death. The relative proportion of each cause depends on age, disease duration and socio-economic context [2, 11].

An important but often underestimated cause is mental and behavioural disorders, which include depression, eating disorders and suicide risk. Diabetic ketoacidosis remains a preventable cause of death, with particular impact in countries with limited access to insulin or specialised management at disease onset. Severe hypoglycemia contributes to mortality both directly (through cardiac arrhythmias or brain injury) and indirectly (through accidents) [1].

Diabetic ketoacidosis (DKA) remains an important cause of mortality in type 1 diabetes, although the frequency of death from DKA has decreased significantly in countries with good healthcare systems. DKA occurs in approximately five patients out of 100 each year, with wide variations depending on different regions of the world. In-hospital mortality during a DKA episode is approximately 0.2% for type 1 diabetes [12].

A critical aspect is post-discharge mortality. Age-adjusted mortality at one year after a DKA episode is 13 times higher than in the general population [13], suggesting that DKA is a very important marker of vulnerability. In low- and middle-income countries, DKA mortality is much higher due to delayed diagnosis and limited access to treatment. Additionally, 25-50% of type 1 diabetes cases are diagnosed in the context of life-threatening DKA, in some cases unfortunately resulting in death [3].

Death from severe hypoglycemia is a rare but serious complication of type 1 diabetes. It contributes to approximately 4-10% of all deaths in T1DM patients [14]. Severe hypoglycemia can cause death through cardiac arrhythmias (particularly QT interval prolongation), seizures, cerebral oedema or accidents (falls, road traffic accidents). Recurrent severe hypoglycemia is an absolute indication for modification of the therapeutic regimen.

Older people with type 1 diabetes have a higher risk of severe hypoglycemia. Continuous glucose monitoring in older adults with type 1 diabetes has identified a large number of hypoglycemic episodes, many of them clinically unrecognised. The use of continuous glucose monitoring systems with alarms and insulin pumps with predictive low-glucose suspension (or better still, closed-loop systems) has significantly reduced the frequency of severe hypoglycemia and associated risks.

Chronic kidney disease (CKD) is one of the strongest predictors of mortality in type 1 diabetes. CKD defined by the combination of urinary albumin excretion rate and decreased glomerular filtration rate triples the risk of death [15]. At any stage of CKD, the risk of death is much greater compared to the risk of reaching dialysis.

CKD accelerates mortality by worsening cardiovascular disease (the leading cause of death), through severe electrolyte disturbances, contributing to anaemia and malnutrition, and reducing available therapeutic options for any disease. Annual screening of urinary albumin excretion and glomerular filtration rate is recommended for all people with type 1 diabetes, starting from five years after diagnosis [8, 15].

The "dead-in-bed" syndrome (sudden, unexplained death in bed) is a rare clinical entity described in young people with type 1 diabetes who are found dead in bed without an obvious cause of death at autopsy. This syndrome was first described in the 1990s. The exact mechanism is not fully elucidated, but research suggests that severe nocturnal hypoglycemia can trigger fatal cardiac arrhythmias, especially in patients with cardiac autonomic neuropathy [16].

Hypoglycemia prolongs the QT interval on electrocardiogram and lowers the threshold for ventricular arrhythmias, which could explain cardiac arrest during sleep. The frequency of this syndrome has decreased with the widespread adoption of continuous glucose monitoring with hypoglycemia alarms and smart insulin pumps.

Yes, there are significant differences in mortality between sexes in type 1 diabetes, and women are disproportionately affected. In the general population, premenopausal women have a lower cardiovascular risk compared to men. In T1DM, although absolute mortality remains higher in men, the difference between men and women decreases greatly. Compared to women in the general population, female T1DM patients have an excess all-cause mortality 40% greater compared to what male T1DM patients experience versus the general population [17].

In other words, type 1 diabetes eliminates the cardiovascular protective effect associated with the female sex. Possible explanations include differences in cardiovascular risk factor management and various hormonal influences.

Yes, mortality in type 1 diabetes varies dramatically between continents and regions of the world. The estimated life expectancy for a 10-year-old child diagnosed with type 1 diabetes ranges between 6 additional years in certain low-income countries and 66 additional years in high-income countries. This 60-year difference reflects profound inequalities in access to insulin, monitoring devices, therapeutic education and functional healthcare systems [3].

North America, Western Europe and Australia (as well as New Zealand) have the highest proportions of people with type 1 diabetes who reach the age of over 65. In Eastern Europe, T1DM-associated mortality is higher than in Western Europe, but significantly lower than in sub-Saharan Africa, the Pacific Islands (Oceania) or the Caribbean.

In Mozambique (Africa), the life expectancy of a child with type 1 diabetes from a rural area can be as low as 7 months. In the Central African Republic, Chad, Guinea-Bissau, Gambia, Niger and Burkina Faso, all in sub-Saharan Africa, a negligible percentage of all people with type 1 diabetes reach the age of 60 [3].

The best outcomes in the world regarding survival of type 1 diabetes patients are found in Finland, Sweden, Norway, Denmark, Germany, Italy, the Netherlands, France, the USA, Canada, Australia, New Zealand and Japan. Japan has the distinctive feature of the highest proportion of total T1DM patients over 60 years of age in the world, explained both by excellent survival and low incidence in children. The United States has significant inequalities related to race, income and health insurance coverage [3].

African-American or Hispanic T1DM patients have a significantly higher risk of death compared to Caucasians. This difference is largely attributed to social and economic inequalities, limited access to quality healthcare, differences in treatment adherence and higher prevalence of cardiovascular risk factors among ethnic minorities [18].

Young African-Americans and Native Americans with type 1 diabetes have significantly higher HbA1c levels compared to Caucasians, and inadequate long-term glycaemic control contributes to increased mortality through cardiovascular and renal complications.

No, mortality in type 1 diabetes is declining globally, but the rate of decline varies greatly between different countries and populations. The annual rate of mortality decline in T1DM patients generally ranges between -2.1% and -5.8%. The excess mortality from T1DM compared to the general population has decreased significantly in Denmark, Scotland and Spain, but has remained relatively stable in Australia, Latvia and the USA [2, 19].

Mortality is declining much more rapidly in developed countries compared to developing ones. The decline in mortality is one of the factors contributing to the increasing global prevalence of type 1 diabetes (from 8.4 million in 2021 to 9.5 million in 2025, a 13% increase) [3]. However, in low-income countries, mortality remains unacceptably high.