Study casts doubt on diabetes screening
Intensive treatment of screen-detected diabetes patients does not achieve statistically significant reductions in mortality and cardiovascular events, UK research has shown.
The researchers from the University of Cambridge, including GP advisers to the Government on vascular screening, presented the study at the American diabetes Association in San Diego this week.
The study analysed data from 3,055 type 2 diabetes patients aged 40 to 69 years – 1,377 given usual care and 1,678 given intensive treatment – all of whom were detected by screening undiagnosed patients using a risk score assessment of general practice medical records at 343 practices in the UK, Denmark, and the Netherlands.
The primary endpoint was first cardiovascular event, including cardiovascular mortality and morbidity, revascularisation, and non-traumatic amputation within five years.
Participating GPs were advised to consider prescribing ACE inhibitors to patients with a blood pressure above 120/80 mm Hg, a cardiovascular risk factor other than diabetes, or those who had had a previous cardiovascular event; 75 mg aspirin daily for patients without contraindications; and a statin to all patients with a cholesterol concentration of 3.5 mmol/L or higher.
Doctors were only provided with diagnostic test results for patients receiving usual care.
The incidence of first cardiovascular event was 7.2%, or 13.5 per 1000 person-years, in the intensive treatment group and 8.5%, or 15.9 per 1000 person-years in the routine care group, a 17% relative risk reduction.
The incidence of all-cause mortality was 6.2% (11.6 per 1000 person-years) and 6.7% (12.5 per 1000 person-years), respectively. Neither difference was significant.
Improvements in cardiovascular risk factors – HbA1c, cholesterol concentrations and blood pressure – were slightly but significantly better in the intensive treatment group.
Study leader Professor Nick Wareham, director of the MRC epidemiology unit at Addenbrookes Hospital, Cambridge, concluded: ‘This trial shows that screening for type 2 diabetes and early intensive multifactorial treatment of the detected patients are feasible in general practice.'
‘When compared with routine care, an intervention to promote target-driven, intensive management of patients with type 2 diabetes detected by screening was associated with small improvements in cardiovascular risk factors, but was not associated with significant reductions in the incidence of cardiovascular events or death over five years.
‘The extent to which the complications of diabetes can be reduced by earlier detection and treatment remains uncertain.'