medwireNews: The decline in mortality from vascular disease means that cancer is now the leading cause of death in people with diabetes, show data from the UK.
The findings are published in The Lancet Diabetes & Endocrinology, with a linked commentary from Mingyang Song (Harvard TH Chan School of Public Health, Boston, Massachusetts, USA).
He writes: “Although vascular complications have been the focus of clinical management of diabetes, the findings by Pearson-Stuttard and colleagues indicate that cancer risk assessment and prevention deserve similar attention by clinicians and patients.”
In 2001, which was the first year of the study, vascular causes accounted for the largest proportion of deaths in people with diabetes, at 44%, but by the final year of the analysis, in 2018, this had declined to 24%.
The absolute number of cancer deaths also declined, but only slightly, so the proportion of deaths from cancer increased from 22% to 28%, leaving it as the top cause of death for people with diabetes in 2018.
These trends also applied to people without diabetes, with vascular disease and cancer respectively accounting for 25% and 27% of deaths in 2018.
Of the other causes of mortality examined, the rates of death due to diabetes, renal and respiratory causes, injuries, and other causes all declined over the study period, whereas there was a large increase in dementia deaths, particularly in the diabetes group, and a very small rise in deaths from liver disease.
Jonathan Pearson-Stuttard (Imperial College London, UK) and co-researchers assessed data for 313,907 people with diabetes, drawn from the UK’s Clinical Practice Research Datalink, and linked these to national mortality data.
The number of people living with diabetes in a given year increased during the study period, from 68,319 in 2001 to 219,547 in 2018. The team matched these by age (per decade) and sex to an equal number of people without diabetes.
The researchers found an overall higher mortality rate among people with diabetes versus those without, which persisted throughout the study period, despite the mortality rate overall declining by approximately a third.
For example, mortality rates in men fell from 40.7 to 27.8 per 1000 person–years in those with diabetes and from 28.4 to 16.7 per 1000 person–years in those without.
Moreover, although the excess mortality in the diabetes group declined over the study period for deaths due to vascular causes, it increased for dementia, diabetes-associated cancers, other cancers, and respiratory diseases.
By 2018, the greatest excess mortality in people with diabetes was seen for non-diabetes cancers, at 2.5 additional deaths per 1000 person–years, followed by dementia and diabetes-related cancers, at 2.3 and 1.7 per 1000 person–years, respectively.
In his commentary, Song notes there is evidence for a metabolic component to cancer, with the risk for many forms, such as liver, pancreatic, endometrial, and gallbladder cancer, being significantly increased in people with diabetes.
“Now with cancer replacing vascular complications as the leading cause of excess death in people with diabetes, enhanced cancer prevention measures should be considered for patients with diabetes, including early cancer screening, behavioural interventions, and chemoprevention,” he says.
He adds that more research is necessary for all these areas, which have not been studied specifically in people with diabetes.
“Also, given the lengthy clinical course of diabetes, it is important to identify the crucial time window during which behavioural intervention might be most useful to lower cancer risk,” he says.
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Lancet Diabetes Endocrinol 2021; doi:10.1016/S2213-8587(20)30431-9
Lancet Diabetes Endocrinol 2021; doi:10.1016/S2213-8587(21)00016-4