Greenfield 1988.

Study characteristics
Methods	Patients' participation in medical care: effects on blood sugar control and quality of life in diabetes RCT (NA clusters and NA providers), conducted in 1) This study was conducted in 2 university hospital outpatient clinics. The first clinic, devoted exclusively to diabetes treatment, was administered by the Endocrinology Division in the Department of Medicine. The second was a general medical ambulatory care (MAC) clinic. 2) Three clinical research assistants delivered the intervention. In United States of America. 2 arms: 1. Control: standard educational material (control arm) and 2. Intervention: patient involvement (intervention arm)
Participants	Control arm N: 34 Intervention arm N: 39, NA, NA Diabetes type: 4 Mean age: 49.67 ± 8.2 % Male: 50.24 Longest follow‐up: 6 months
Interventions	Control arm: standard educational material 1) Patient education 2) Promotion of self‐management Intervention arm: patient involvement 1) Case management 2) Patient education 3) Promotion of self‐management
Outcomes	Glycated haemoglobin
Funding source	Supported by a grant (AM27547) from the National Institute for Arthritis, Diabetes, Digestive and Kidney Diseases
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Patient's baseline characteristics (selection bias)	Low risk	Table 1 notes indicate that all measurements are similar.
Patient's baseline outcomes (selection bias)	Low risk	Table 1 notes indicate that all measurements are similar. Table 2 for HbA1c.
Incomplete outcome data (attrition bias)	High risk	Loss of 8/34 in control (24%), loss of 6/39 in intervention (15%). Reasons for dropout not provided.
Blinding of participants and personnel (performance bias) and of outcome assessors (detection bias)	Low risk	Objective measure for HbA1c.
Selective reporting (reporting bias)	Unclear risk	No registered protocol. Methods match outcomes. No follow‐up on several baseline measurements.
Risk of contamination (other bias)	Unclear risk	Patient‐randomised. The same physicians were taking care of control and intervention patients. Physicians might have changed their approach after seeing intervention patients. Research assistants administering the intervention were not blind to the patient's study group and could have been differentially enthusiastic in delivering one intervention over the other. Care was taken in training the assistants to avoid bias in intervention administration, including use of standardised materials and review of sample tapes of assistant‐patient interactions. Although personal styles of administration varied, there were no discernible biases in intervention delivery.
Other bias	Low risk	None identified.