Griffin 2011.

Study characteristics
Methods	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 Cluster‐RCT (343 clusters and NR providers), conducted in general practices in Denmark, The Netherlands and UK 2 arms: (control arm) (intervention arm)
Participants	Control arm N: 1379 Intervention arm N: 1678, NA, NA Diabetes type: 2 Mean age: NR ± NR % Male: 57.9 Longest follow‐up: 60 months
Interventions	Control arm: (routine care) Intervention arm: 1) Case management 2) Audit and feedback 3) Clinician education 4) Patient education 5) Patient reminder
Outcomes	Anti‐platelet drugs Lipid‐lowering drugs Antihypertensive drug Glycated haemoglobin Systolic blood pressure Diastolic blood pressure Low‐density lipoprotein Hypertension control Smoking status
Funding source	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
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Minimisation was used.
Allocation concealment (selection bias)	Low risk	Cluster.
Provider's baseline characteristics (selection bias)	Low risk	Reported in text, but not in table; no major differences.
Patient's baseline characteristics (selection bias)	Low risk	Reported in text, but not in table; no major differences.
Patient's baseline outcomes (selection bias)	Unclear risk	No mention in text and no P values in table.
Incomplete outcome data (attrition bias)	High risk	~19% lost to follow‐up in control group; ~27% in intervention group; not balanced. Reasons why 2 patients withdrew consent in the control group not reported.
Blinding of participants and personnel (performance bias) and of outcome assessors (detection bias)	Low risk	Primary: microvascular outcomes. Used standardised equipment and outcome assessors were blinded.
Selective reporting (reporting bias)	High risk	Information not available.
Risk of contamination (other bias)	Low risk	Cluster.
Other bias	Low risk	Information not available.