Mortality in type 1 diabetes

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 than people without diabetes. This risk varies significantly with age, disease duration and quality of glycemic 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 type 1 diabetes 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 is a statistical average, not an individual prediction: it shows how many more years a person of a given age has left to live, on average. 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 type 1 diabetes 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, in low- and middle-income countries access to treatment is greatly delayed. That is why, globally, approximately one in 15 people newly diagnosed with type 1 diabetes is estimated to die at the time of onset [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 behavioral disorders;
• diabetic foot;
• elevated LDL cholesterol, that is, the cholesterol fraction deposited in the artery walls;
• HbA1c values above 8% (64 mmol/mol) [1] [5].

Additionally, untreated arterial hypertension, smoking and a sedentary lifestyle contribute to the increased mortality risk. Arterial stiffness (the loss of elasticity of the artery walls) is also an independent predictor of mortality in type 1 diabetes [6]. It is called independent because it predicts the risk of death even after the other factors have been taken into account. It is essential that each risk factor is identified and treated early, as their effect is cumulative. The combination of poor glycemic control and chronic kidney disease or cardiovascular disease multiplies the risk.

Glycated hemoglobin (HbA1c) plays an essential role in reducing long-term mortality in type 1 diabetes. A period of intensive glycemic control produces benefits that are maintained for decades, even if that level of control subsequently deteriorates. This phenomenon is called "metabolic memory" [7]. In the first 5–10 years after onset, a lower HbA1c confers a significantly lower risk of cardiovascular and renal complications and of death. The benefit holds even after 30 years, although glycemic control has relaxed in the meantime.

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 must be lowered without increasing the frequency of severe hypoglycemia. This is why continuous glucose monitoring systems and smart insulin pumps matter so much.

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 the classic causes and those related to insulin treatment. The association of obesity with type 1 diabetes is sometimes called "double diabetes". The name reflects the overlap between the insulin deficiency specific to type 1 and the insulin resistance characteristic of type 2 [9].

Obesity worsens glycemic 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;
• 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 behavioral disorders, which include depression, eating disorders and suicide risk. The signs that call for immediate help and what to do then are in the medical disclaimer. Diabetic ketoacidosis remains a preventable cause of death, with particular impact in countries with limited access to insulin or specialized 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 5 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. Mortality in the first year after a DKA episode is 13 times higher than in people of the same age in the general population [13]. This shows 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]. If vomiting, difficulty breathing or drowsiness appear, go to the emergency room straight away.

Death from severe hypoglycemia is a rare but serious complication of type 1 diabetes. It contributes to approximately 4–10% of all deaths in type 1 diabetes patients [14]. Severe hypoglycemia can cause death through cardiac arrhythmias (especially through prolongation of the QT interval, a change on the electrocardiogram that favors dangerous rhythms), seizures, cerebral edema or accidents (falls, road traffic accidents). Severe hypoglycemia means that the person can no longer help themselves and needs someone else's help to recover. If loss of consciousness or a seizure occurs, call an ambulance immediately. 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 unrecognized. Two technologies have significantly reduced the frequency of severe hypoglycemia and its associated risks: continuous glucose monitoring systems with alarms and insulin pumps with predictive low-glucose suspension. Closed-loop systems protect better still.

Chronic kidney disease (CKD) is one of the strongest predictors of mortality in type 1 diabetes. CKD is defined by an increase in the urinary excretion of albumin (a protein that reaches the urine when the kidney's filter deteriorates) and by a fall in the glomerular filtration rate (how much blood the kidneys filter in a minute). This combination 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 through:

• worsening of cardiovascular disease (the leading cause of death);
• severe electrolyte disturbances;
• contribution to anemia and malnutrition;
• reduction of the therapeutic options available for any disease.

Annual screening of urinary albumin excretion and glomerular filtration rate is recommended for all people with type 1 diabetes, starting from 5 years after diagnosis [8] [15].

Sudden, unexplained death in bed (known in the medical literature as the "dead-in-bed" syndrome) is a rare clinical entity. It describes young people with type 1 diabetes who are found dead in bed, with no 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 (damage to the nerves that automatically regulate the heart rhythm) [16].

Hypoglycemia prolongs the QT interval on the 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 type 1 diabetes, although absolute mortality remains higher in men, the difference between men and women decreases greatly. Women with type 1 diabetes have an excess all-cause mortality compared with women in the general population. This excess is 40% greater than the one recorded by men with type 1 diabetes compared with men in 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, type 1 diabetes-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 stands out with the world's highest proportion of type 1 diabetes patients over 60 years of age. Two things explain it: 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 type 1 diabetes 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. Inadequate long-term glycemic control then raises 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. In type 1 diabetes patients, mortality generally falls by 2.1–5.8% a year. The excess mortality of type 1 diabetes versus the general population has fallen significantly in Denmark, Scotland and Spain, but stayed 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 driving the rising global prevalence of type 1 diabetes. Prevalence went 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.