Decreased mortality could explain increased type 2 diabetes prevalence

A new study suggests that longer survival of patients with type 2 diabetes could explain increasing prevalence of the condition.
These findings indicate, therefore, that rising rates of type 2 diabetes might not necessary be due to increased incidence, but declining mortality.
Dr Stephanie Read, University of Edinburgh and colleagues evaluated trends in type 2 diabetes incidence and mortality rates between 2004-2013 by age, sex and socioeconomic deprivation.
Data on diabetes diagnosis, population estimates and number of deaths each year was collected from the Scottish Care Information – Diabetes database and National Records Scotland. The age range evaluated was 39-90.
Overall, there were 180,290 incident cases of type 2 diabetes in Scotland between 2004-2013. Incidence generally remained stable during this time, but there were a number of variations in the findings.
Incidence increased among young men, remained stable in young women and declined in older men and women. Incidence also declined across all socioeconomic groups but increased after 2008 in the most deprived groups.
Because the distribution of demographic characteristics across Scotland is stable, the researchers report that trends in diabetes prevalence are influenced by the balance found in incidence and mortality changes.
Standardised mortality rates declined for both men and women during the study period, with similar reductions found across all ages and deprivation groups. The most deprived groups had higher mortality rates than the least deprived groups.
The authors wrote that the increased prevalence of type 2 diabetes could be primarily attributed to declining mortality, rather than increasing numbers of patients developing the condition.
They noted a stabilisation in the incidence of adult obesity, which can increase the risk of type 2 diabetes, as well as improvements in HbA1c among patients who participated in the 2014 Scottish Diabetes Survey.
The researchers added that the decline in mortality might not be due to either earlier diagnosis or improvements in diabetes care.
“Despite improved mortality rates, type 2 diabetes confers an excess risk of death compared with the non-diabetic population … there is still scope to address the increased mortality associated with diabetes,” said the authors.
“Major inequalities by age, sex and socioeconomic status in type 2 diabetes incidence and mortality indicate that effective approaches to treatment and control will need to address existing inequalities.”
The findings appear in the online journal Diabetologia.