STOCKHOLM — Screening for prevalent type 2 diabetes in primary care identified people at high modifiable cardiovascular risk, but subsequent intensive multifactorial treatment improved cardiovascular outcomes by only an insignificant 17% over routine care in a large 5-year randomized study.
Dr. William H. Herman (left), Dr. Simon Griffin (right)
Nevertheless, “when compared to no screening and no diabetes treatment, screening and either early routine diabetes care or intensive multifactorial treatment are likely to reduce cardiovascular morbidity and mortality by nearly half,” Dr. William H. Herman, who was not involved in the research, commented at the annual meeting of the European Association for the Study of Diabetes.
Indeed, the difference between the intensive intervention and routine treatment groups is not the main point of the ADDITION study, said Dr. Herman, professor of medicine at the University of Michigan, Ann Arbor, who served as the independent commentator on the study. “The reality is that once people were labeled with diabetes they achieved much better risk factor control ... During the time this community-based study was being conducted, there were major national and international initiatives to improve diabetes care, and they clearly had an impact on blood pressure, cholesterol, smoking, and glycemia,” Dr. Herman said in an interview. “It’s the combination of screening, diagnosis, and treatment that seemed to have an impact.”
As part of the Anglo-Danish-Dutch Study of Intensive Treatment In People With Screen Detected Diabetes in Primary Care (ADDITION), 76,308 people aged 40-69 years without known diabetes were screened in 334 primary care practices in Denmark, Great Britain, and the Netherlands beginning in 2000. Those found to have diabetes were invited to enter the ADDITION treatment study at one of five participating centers. The screening results, published previously, showed that individuals with screening-detected type 2 diabetes and included in the ADDITION study had a raised and potentially modifiable risk of coronary heart disease (CHD). Specifically, the median estimated 10-year risk of CHD was 11% in women and 21% in men (Diabetologia 2008;51:1127-34).
Dr. Simon Griffin of the Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, England, presented the 5-year ADDITION outcome results for 1,379 randomized to routine care and 1,678 who received intensive multifactorial intervention. At baseline, patients were aged 60 years, had a mean body mass index of 32 kg/m2, and slightly more than half were male. Before diabetes diagnosis, less than half – about 40% – were on antihypertensive medication and only 15% were on statins, despite having a mean blood pressure of approximately 150/86 mm Hg and mean LDL cholesterol levels of 131 mg/dL.
The intensive intervention included structured lifestyle education (dietary modification, increased physical activity, and smoking cessation) and intensive treatment of blood glucose, blood pressure and lipids, and prophylactic aspirin with or without motivational interviewing.
Over the 5-year study period, treatment with antihypertensive medication, statins, and aspirin increased dramatically in both groups, although to a slightly greater degree in the intensive treatment group. At 5 years, statin use was 68% for the routine care group and 78% for intensive treatment, daily aspirin was used by 40% and 69%, and glucose-lowering medication by 54% and 64%, respectively, Dr. Griffin reported.
The proportion of patients achieving targets for blood pressure, cholesterol, and glycemia – targets that changed over the study period based on national guidelines – increased in both groups but was slightly greater with intensive treatment. The primary outcome composite of cardiovascular mortality, nonfatal myocardial infarction, nonfatal stroke, revascularization as a first event, and amputation did not differ significantly between the routine and intensive treatment groups at 8.5% vs. 7.2%, with a hazard ratio of 0.83. All-cause mortality, a secondary outcome, also did not differ significantly, with a hazard ratio of 0.91, Dr. Griffin said.
Dr. Griffin noted that the mortality rate in both groups was low, and even in the routine care group it was lower than that of the general diabetes population in Denmark and only slightly higher than the age-matched Danish general population.
The ADDITION study was funded by unrestricted grants from Novo Nordisk A/S (main industry sponsor), ASTRA Denmark, Pfizer Danmark, GlaxoSmithKline Pharma Denmark, SERVIER Danmark, A/S HemoCue Danmark, and A/S Novo Nordisk Scandinavia AB. Research funds also were contributed by the Danish Council for Strategic Research, Danish Research Foundation for General Practice, Danish Centre for Evaluation and Health Technology Assessment, the Aarhus University Research Foundation, Novo Nordisk Foundation, the National Board of Health, the Danish Medical Research Council, the Danish Diabetes Association, the A.P. Møller Foundation for the Advancement of Medical Science, the Bernhard and Marie Kleins Trust, the Centre for Innovation in Nursing Education, the County of Aarhus, and the Danish Council of Nursing.