Hiss 2001.

Study characteristics
Methods	Comprehensive evaluation of community‐based diabetic patients: effect of feedback to patients and their physicians: a randomized controlled trial RCT (NA clusters and NA providers), conducted in 1) We selected 4 Michigan communities, 2 large and 2 small, from a pool of Michigan communities. Patients attend a specially arranged clinic in their community where they could be examined and followed (The Michigan Diabetes Research and Training Center‐MDRTC). 2) The intervention was delivered by the project diabetes nurse specialists. In United States of America. 2 arms: 1. Control (mailed health report) (control arm) and 2. Intervention (health report and counselling) (intervention arm)
Participants	Control arm N: 190 Intervention arm N: 186, NA, NA Diabetes type: 2 Mean age: 64.05 ± NR % Male: 42.82 Longest follow‐up: 12 months
Interventions	Control arm: (mailed health report) 1) Electronic patient registry 2) Facilitated relay of clinical information Intervention arm: (health report and counselling) 1) Case management 2) Electronic patient registry 3) Facilitated relay of clinical information 4) Patient education
Outcomes	Glycated haemoglobin Systolic blood pressure Diastolic blood pressure
Funding source	This study was supported by National Institutes of Health Grant 5‐P60‐DK‐20572, the National Institute of Diabetes and Digestive and Kidney Diseases
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	As patients entered the study, they were randomly assigned using a random number table.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Patient's baseline characteristics (selection bias)	Low risk	The baseline demographics were similar for all 4 high‐risk groups (Table 1)
Patient's baseline outcomes (selection bias)	Low risk	The baseline demographics were similar for all 4 high‐risk groups (Table 1).
Incomplete outcome data (attrition bias)	High risk	62 patients missing out of 376 for post‐intervention data (16.5%). 15.1% in the intervention group and 17.9% in the control group. Reasons partly reported and some are unbalanced (death and lost).
Blinding of participants and personnel (performance bias) and of outcome assessors (detection bias)	Low risk	All outcomes were objectively measured (HbA1c, SBP and DBP).
Selective reporting (reporting bias)	High risk	No registered protocol. In the methods, patients were tested for LDL, HDL, knowledge, height, weight, etc. at baseline, but these outcomes are not reported after intervention.
Risk of contamination (other bias)	Unclear risk	Only those in intervention group met with project nurses, but physicians met with patients in both groups; interaction with the nurses and patients in intervention group may have influenced care of those in control group. Furthermore, a comprehensive evaluation report for all patients were sent by email to physicians. Physicians might have changed their regular care with control patients.
Other bias	Low risk	No evidence of other bias.