Diabetes screening might not reduce deaths, study suggests
4 October 2012
In the first ever randomised controlled trial of diabetes screening, researchers found no evidence that testing people for the disease reduces the number of deaths from any cause (including those unrelated to diabetes) after ten years. The results contradict several previous studies, which had suggested that a widespread screening programme would be effective at reducing deaths.
Dr Simon Griffin, from the MRC Epidemiology Unit in Cambridge, said: "Our study was the first robust evaluation of diabetes screening, and the results suggest its effectiveness may have been overestimated. Based on our findings, screening is only likely to benefit the small minority of people living with undiagnosed diabetes and is unlikely to reduce deaths in the general population."
Assessment for diabetes is currently included in the NHS Health Checks programme offered to all those aged between 40 and 74 in the UK. The disease has many attributes that make it a good candidate for population screening: it's relatively common and incidence is rising; it takes a long time to develop, so there is a large window for early detection; and early treatment can minimise the risk of complications developing over time.
There has been some uncertainty around the benefits of population-based screening for type 2 diabetes. Although several studies have suggested that a screening programme would be effective, these were based largely on computer simulations. This study set out to evaluate such screening by looking at one measure of effectiveness - whether it reduced deaths.
The researchers studied more than 20 000 people aged between 40 and 69 and registered at 32 GP practices in the east of England, which were randomly allocated to screening clinics or control clinics with no screening. In the screening clinics, patients at high risk of developing diabetes were tested for the condition, and of these 2.9 per cent were diagnosed with the disease.
All participants, with and without diabetes, were then followed up for an average of 9.6 years. After this time, the researchers found no significant difference in the total number of deaths in the screened group and the control group.
There were also no differences in the rates of death attributed to cardiovascular conditions, cancer or diabetes-related causes. Cancer was the most common cause of death.
The study only looked at one geographical region, which had a largely Caucasian population and a higher than average socioeconomic status. It is possible that the results would be different in other areas of the UK and in other countries.
"While this doesn't necessarily mean that screening for diabetes is invalid, it does suggest that tackling the diabetes epidemic is likely to require a more holistic approach using a combination of preventative strategies aimed at detecting and treating the disease early and reducing the risk of it developing in the first place," added Dr Griffin.
The study was funded by the Wellcome Trust, MRC, NHS and the National Institute of Health Research. Investigating chronic diseases such as type 2 diabetes is one of the Wellcome Trust's core strategic research challenges.
Image credit: Wellcome Library, London.
