Individuals with type 1 diabetes lose almost 8 years of life compared to those without diabetes, whilst those with type 2 diabetes lose almost 2 years, suggests a population-level analysis of mortality data.
The research was presented at the EASD Virtual Meeting 2020 on September 22, and also published in Cardiovascular Endocrinology & Metabolism.
For the study, publicly available data from NHS Digital and the Office of National Statistics (ONS) was combined into a model to compare the predicted life expectancy of people with type 1 and type 2 diabetes with that of those without diabetes in England.
They found that an average individual with type 2 diabetes is expected to live 1.7 years less than someone without the condition, rising to 7.6 years less for someone with type 1 diabetes.
These numbers were even higher in women than in men.
The researchers also calculated that for every year a diabetes patient spends with their HbA1c level over 58mmol/mol, they lose around 100 life days.
"Clearly these figures are quite sobering, given the effort that goes into diabetes management," said Mike Stedman, from the Res Consortium, Andover, Hampshire, who led the study alongside Dr Adrian Heald, from the University of Manchester.
He noted that the results demonstrate "we have more work to do" to get patients to the stage where "diabetes does not shorten life expectancy".
The authors add: "Communication of life years lost from now, to patients at the time of consultation with healthcare professionals and through messages publicised by advocacy groups such as Diabetes UK...will be of great help."
Lucy Chambers, head of research communications at Diabetes UK, which was not involved in the research, said: "This research highlights the seriousness of diabetes, and the significant impact the condition and its complications has on the lives of those living with it.
"It’s worrying to see that those living with diabetes, particularly those with type 1, are still at risk of a shorter life expectancy."
Calling for more research into the increase in years lost in women, Lucy Chambers added: "While numbers like this can be alarming, we know that keeping blood sugar levels within a healthy range reduces the risk of complications, which this research shows may also extend life expectancy."
Tobias Bøggild-Damkvist, a diabetes activist with the think tank Type1, from Copenhagen, Denmark, commented that the figures make for "very depressing reading", but are "important".
However, he underlined that the research "should be used for prioritising initiatives to improve treatment," and not to simply "scare" patients into changing their behaviour.
The researchers note that the "sustained growth" in the number of patients with diabetes means that "effective early diagnosis and treatment...is vital" to avoid long-term comorbidities.
To determine the impact of sup-optimal management on overall life expectancy for patients with diabetes, they gathered data from the ONS on mortality rates and projected life expectancy, stratified by age and sex, for the years 2015–2017.
They also obtained mortality rates for people with type 1 and type 2 diabetes for the years 2015–2016 from the National Diabetes Audit (NDA), with the data divided into five age groups and by sex, expressed as a ratio to the general population.
The team employed a model to apply the relative NDA mortality rates to the general population for each age and sex, and calculated the life expectancy of type 1 and type 2 diabetes populations, as well as for the non-diabetes population.
In all, data on 41.3 million individuals registered at 6165 general practices were included in the analysis, of whom 217,000 were on the type 1 diabetes register and 2.5 million on the type 2 diabetes register.
The team calculated that the average age of someone with type 1 diabetes in their cohort was 42.8 years, with a calculated future life expectancy of 32.6 years.
This compared with a future life expectancy of 40.2 years for an equivalent person without diabetes from the general population, which corresponds to an average lost life years (LLY) of 7.6 years per average person for someone with type 1 diabetes.
The average age of a person with type 2 diabetes in their study was 65.4 years, with a calculated future life expectancy of 18.6 years.
In contrast, the average life expectancy for an equivalent person from the general population was 20.3 years, meaning that someone with type 2 diabetes had a LLY of 1.7 years per average person.
The results also showed that the LLY per person for women was higher than that for men, increasing by 21% in women with type 1 diabetes compared to their male counterparts, and by 45% in women with type 2 diabetes.
"More work is required to understand why women are losing more life years than men," the team says.
Next, they reasoned that lost life years can be seen as a result of sub-optimal condition management, which in this case can be viewed as poor glycaemic control, as measured by HbA1c levels.
The total number of lost life days was therefore allocated to the total number with higher HbA1c results and expected non-diabetes life expectancy to determine the number of life-days lost per life year with high HbA1c.
This showed that for every year an individual with type 1 or type 2 diabetes spent with an HbA1c level greater than 58 mmol/mol their life could be shortened by approximately 100 life days.
The data indicated that 70% of type 1 diabetes patients and 33% of those with type 2 diabetes had an HbA1c level >58 mmol/mol at their last check-up.
"Knowledge of this may act as an incentive for clinicians to ensure that all people are on the best therapy to keep their blood sugar in the target range, and for those people to engage more strongly with their therapy and lifestyle recommendations," the team writes.
They acknowledge that there are limitations to their study, including its reliance on national-level mortality data, and the inability to control for smoking, inactivity, overweight, hypertension and statin use.
No funding declared.
No relevant financial relationships declared.
EASD Virtual Meeting 2020: Abstract 265. Presented September 22.
Cardiovascular Endocrinology & Metabolism 2020. doi: 10.1097/XCE.0000000000000210