Effect of early intensive multifactorial therapy on 5-year cardiovascular outcomes in individuals with type 2 diabetes detected by screening (ADDITION-Europe): a cluster-randomised trial

Abstract

Background: Intensive treatment of multiple cardiovascular risk factors can halve mortality among people with established type 2 diabetes. We investigated the effect of early multifactorial treatment after diagnosis by screening.

Methods: In a pragmatic, cluster-randomised, parallel-group trial done in Denmark, the Netherlands, and the UK, 343 general practices were randomly assigned screening of registered patients aged 40-69 years without known diabetes followed by routine care of diabetes or screening followed by intensive treatment of multiple risk factors. The primary endpoint was first cardiovascular event, including cardiovascular mortality and morbidity, revascularisation, and non-traumatic amputation within 5 years. Patients and staff assessing outcomes were unaware of the practice's study group assignment. Analysis was done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00237549.

Findings: Primary endpoint data were available for 3055 (99·9%) of 3057 screen-detected patients. The mean age was 60·3 (SD 6·9) years and the mean duration of follow-up was 5·3 (SD 1·6) years. Improvements in cardiovascular risk factors (HbA(1c) and cholesterol concentrations and blood pressure) were slightly but significantly better in the intensive treatment group. The incidence of first cardiovascular event was 7·2% (13·5 per 1000 person-years) in the intensive treatment group and 8·5% (15·9 per 1000 person-years) in the routine care group (hazard ratio 0·83, 95% CI 0·65-1·05), and of all-cause mortality 6·2% (11·6 per 1000 person-years) and 6·7% (12·5 per 1000 person-years; 0·91, 0·69-1·21), respectively.

Interpretation: An intervention to promote early intensive management of patients with type 2 diabetes was associated with a small, non-significant reduction in the incidence of cardiovascular events and death.

Funding: National Health Service Denmark, Danish Council for Strategic Research, Danish Research Foundation for General Practice, Danish Centre for Evaluation and Health Technology Assessment, Danish National Board of Health, Danish Medical Research Council, Aarhus University Research Foundation, Wellcome Trust, UK Medical Research Council, UK NIHR Health Technology Assessment Programme, UK National Health Service R&D, UK National Institute for Health Research, Julius Center for Health Sciences and Primary Care, University Medical Center, Utrecht, Novo Nordisk, Astra, Pfizer, GlaxoSmithKline, Servier, HemoCue, Merck.

Figure 1

Trial profile

Figure 2

Cumulative incidence and relative risk of composite cardiovascular endpoint (A) Cumulative incidence curves by treatment group. The p value was calculated with Cox's regression and fixed-effects meta-analysis. (B) HRs of development of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and revascularisation as a first event (secondary endpoints), and these cardiovascular events combined (primary endpoint), by country and overall. HR=hazard ratio. CVD=cardiovascular disease.

Figure 3

Cumulative incidence and relative risk of all-cause mortality (A) Kaplan-Meier survival estimates by treatment group. (B) HRs of all-cause mortality, by country and overall. HR=hazard ratio. CVD=cardiovascular disease.

Figure 4

Proportion of patients for whom cardiovascular risk factor values were below the intensive treatment intervention target thresholds at baseline and after 5 years of follow-up 1 SE are shown. CVD=cardiovascular disease. HbA_1c=glycated haemoglobin A_1c.