(15th August 2013)
Overview: The prevalence of type 2 diabetes increases with age: in the UK, 1 in 20 people older than 65 years has diabetes, compared with 1 in 5 people older than 85 years. However, type 2 diabetes is increasingly diagnosed in children and adolescents. Mortality is 2 to 3 times higher among people with type 2 diabetes than in the general population, largely due to an increase in cardiovascular mortality.
See the NICE Evidence Services topic page for type 2 diabetes for an overview of the condition.
Current advice: The NICE clinical guideline on type 2 diabetes (which is currently beingupdated) covers the management of this condition. NICE guidance does not cover population screening for type 2 diabetes. The UK National Screening Committee's policy is that general population screening for diabetes should not be offered.
A diabetes risk assessment is offered to people aged 40–74 years in England as part of theNHS Health Check.
New evidence: Simmons et al. (2012) reported results of screening for type 2 diabetes from a cluster randomised controlled trial (ADDITION-Cambridge) in 33 general practices in eastern England. First a diabetes risk score was calculated for eligible patients, and diabetes screening was offered to those at high risk (n=15,089). Screening was attended by 11,737 people and diabetes was diagnosed in 466 participants. The general practices performing the screening included 15 practices that subsequently took part in an intensive treatment intervention and 13 practices that then offered patients usual care. In the 5 control practices (n=4137) the risk of diabetes was calculated but no screening was done.
The primary outcome of all-cause mortality after median follow-up of 9.6 years did not differ significantly between the screening and control groups (hazard ratio [HR]=1.06, 95% confidence interval [CI] 0.90 to 1.25, p=0.46). Similarly no significant differences were seen for the secondary outcomes of cardiovascular mortality, cancer mortality, or other causes of death. People who were invited to attend screening but did not were more likely than those who did attend to be men, younger, and more obese, and were less likely to be taking antihypertensive drugs and had higher all-cause mortality (adjusted HR=2.01, 95% CI 1.74 to 2.32).
The authors noted that combining the practices offering intensive treatment with those offering usual care after screening increased the sample size of the screening group but may also increase confounding and selection bias. The demographics of practices in this study served less deprived areas than the average English practice so the results may not be directly applicable to more disadvantaged populations, in which risk of diabetes may be higher and likelihood of attending screening may be lower.
Commentary: "Type 2 diabetes is a huge, and increasing, public health problem. Its relationship with cardiovascular disease, dementia and shortened lives is well documented so the question of how best to reduce this burden of ill health arises. We know from other work that intensive lifestyle interventions in people at high risk of developing diabetes can reduce the onset of the disease and we know that good management in people with diabetes will reduce complications and deaths.
"Many people believe that picking people up earlier in the disease process would provide health benefits. This natural desire to help often leads us to make far reaching assumptions so it is incredibly important that we examine whether these assumptions are correct and whether the application of resources will really help. This evidence does not add to the rationale for screening and treatment of diabetes but does demonstrate that people diagnosed with diabetes through screening were at high risk of cardiovascular disease, with high prevalence of modifiable risk factors such as overweight, high blood pressure and high cholesterol levels. The UK National Screening Committee is due to update its view on screening for type 2 diabetes this year and will use the conclusions from ADDITION to inform its recommendations." – Dr Anne Mackie, Director of the UK National Screening Committee