SAN DIEGO – Early, multifactorial intervention in patients who were diagnosed with type 2 diabetes through screening reduced the incidence of cardiovascular events and death, albeit nonsignificantly, in a large, randomized controlled trial.
At the time of diagnosis, many patients with type 2 diabetes already have evidence of diabetic complications and potentially modifiable cardiovascular risk factors. Modeling studies have indicated that routine diabetes screening might be an efficient use of resources, but there has been no previous evidence from trials showing whether early intensive multifactorial treatment improves outcomes following detection by screening, said Dr. Simon J. Griffin, of the MRC Epidemiology Unit, Institute of Metabolic Science, Cambridge, England, and his associates.
Results of the Anglo-Danish-Dutch Study of Intensive Treatment in People With Screen Detected Diabetes in Primary Care (ADDITION-Europe) were presented by Dr. Griffen at the annual scientific sessions of the American Diabetes Association and simultaneously published online June 25 in the Lancet (2011 June 25 [doi:10.1016/S0140-6736(11)60698-3]).
The study used a cluster design, in which 343 general practices were randomized from April 2001 to December 2006 to routine diabetes care or intensive multifactorial treatment. A total of 157 of the practices randomized to routine care and 161 to intensive care completed screening and included eligible patients. Screening involved either calculation of a risk score followed by capillary glucose testing, or an oral glucose tolerance test.
The intensive-treatment intervention involved the stepwise addition of medications and promotion of healthy lifestyles aimed at achieving target-driven and guideline-driven management of hyperglycemia, blood pressure, and cholesterol levels. The same approach was used across all centers, although final decisions about prescriptions, including choice of individual drugs, were made by physicians and patients, Dr. Griffen and his associates said.
In all, 3,057 screen-identified patients aged 40-69 years were included. The mean follow-up period was 5.3 years, during which 238 first cardiovascular events occurred. The primary end point, a composite of cardiovascular events, occurred in 8.5% of the routine-care patients and 7.2% of the intervention group. The difference was statistically nonsignificant, with a hazard ratio (HR) of 0.83.
Trends were in favor of the multifactorial intervention for the composite components cardiovascular death, myocardial infarction, stroke, revascularization, and total mortality, but none of these achieved statistical significance. Differences were greatest for myocardial infarction (2.3% vs. 1.7%; HR, 0.7) and smallest for stroke (1.4% vs. 1.3%; HR, 0.98). Another component, amputation, did not occur as a first event in either group.
In both groups, more patients had values below target thresholds for hemoglobin A1c concentrations, blood pressure, and cholesterol concentrations at follow-up than at baseline, but the proportion of patients meeting the targets was higher in the intensive-treatment group than in the routine-care group. The proportions of patients reporting hypoglycemia did not differ, the investigators said.
One possible explanation for the lack of a stronger effect is that the trial took place at a time of improved diabetes care delivery in general practice, which might have minimized the differences between the groups. At follow-up, mean HbA1c values were 6.7% for routine care and 6.6% for intensive treatment, down from 7.0% in both groups at baseline. Systolic blood pressure was 138.1 mm Hg with routine care and 134.8 mm Hg with intensive intervention, down from 149.8 and 148.5, respectively.
It’s also possible that the follow-up wasn’t long enough. The event rate was lower than expected at 5 years, but the values appeared to diverge at about 4 years, suggesting that further follow-up is justified to test whether early intensive multifactorial treatment reduces cardiovascular risk in the long term, the investigators concluded.
The trial was given unrestricted grants from Novo Nordisk AS, Novo Nordisk Scandinavia AB, Novo Nordisk UK, ASTRA Denmark, Pfizer Denmark, GlaxoSmithKline Pharma Denmark, Servier Denmark, and HemoCue Denmark.