No CV benefit of intensive therapy in type 2 diabetes: ADDITION published

Emma Hitt

June 27, 2011

San Diego, CA - Findings from the ADDITION-Europe study, showing no significant improvements in mortality and cardiovascular events with "intensive" treatment in patients with type 2 diabetes, have now been published in the Lancet[1]. The ADDITION results were first reported by heartwire after their presentation at the European Association for the Study of Diabetes last year; they were highlighted over the weekend at a press briefing hosted by the journal here at the American Diabetes Association (ADA) 2011 Scientific Sessions .

According to investigators, intensive multifactorial treatment improved cardiovascular risk factors, compared with usual care, in patients diagnosed with type 2 diabetes identified through screening in general practice, but those improvements were very small and did not translate into lower event rates. There was only a trend toward a reduction in mortality and cardiovascular events (including MI, stroke, and amputation) in intensively treated patients, reported principal investigator Dr Simon J Griffin (Institute of Metabolic Science, Cambridge, UK).

As previously reported by heart wire , the objective of this study was to evaluate whether early intensive multifactorial treatment might improve outcomes, compared with usual care, if initiated soon after detection by screening and before clinical diagnosis.

The study consisted of 3055 patients (mean age 60 years) found to have type 2 diabetes on screening; 1377 received usual care and 1678 received intensive treatment. Intensive treatment consisted of usual care plus additional target- and guideline-driven management of hyperglycemia, blood pressure, and cholesterol levels by medical treatment and the promotion of healthy lifestyles, based on the stepwise regimen used in Steno-2 and other trials.

Patients were followed for a mean of 5.3 years. Intensive treatment was associated with slightly but significantly increased prescription of treatments and improvements in cardiovascular risk factors (blood pressure and levels of cholesterol and glycosylated hemoglobin [HbA1c]), but greater use of these medications and subsequent risk-factor improvement did not translate into lower CV events.

"Although there is no evidence of harm associated with screening and intensive therapy, the extent to which the complications of diabetes can be reduced by earlier detection and treatment remains unclear," Griffin and colleagues note. "Differences were greatest for myocardial infarction and smallest for stroke," they add.

During the first two to three years of follow-up, "the event rate was almost the same between the two groups, and then the differences started to magnify," said Dr Torsten Lauritzen (Aarhus University, Denmark) during the press briefing. "We are going to follow the patients for another five years. Hopefully we will see an increasing difference between the two groups," he said in an interview.

"One thing that strikes me about this study is how well the routine-care group was treated," said Dr Sue Kirkman, ADA senior vice president, during the press conference. "The fact that you didn't see a significant difference might be because the routine-care patients had excellent care, which would have minimized the difference between the two groups," she said.

In a related comment published in the Lancet[2], Drs David Preiss and Naveed Sattar (University of Glasgow, Scotland) noted that the lipid-lowering and antihypertensive therapies now used in the standard care of patients with type 2 diabetes might have diminished the apparent benefit of intensive therapy observed in ADDITION-Europe.

"The key questions now are whether a sizable reduction in the lead time between diabetes onset and clinical diagnosis can be achieved by implementation of simpler diagnostic criteria (ie, HbA1c) and, if so, to what extent this development might further reduce cardiovascular and mortality risks in patients with diabetes," Preiss and Sattar note.

Commercial sources of funding included Novo Nordisk, AstraZeneca, Pfizer, GlaxoSmithKline, Servier, HemoCue, and Merck. The researchers and editorialists have disclosed no relevant financial relationships.

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