Katon 2010.

Study characteristics
Methods	Collaborative care for patients with depression and chronic illnesses Patient RCT, conducted in 14 primary care clinics (within a Group Health Cooperative) in Washington State, USA Two arms: 1. Usual care group (control arm) and 2. Intervention group (intervention arm)
Participants	Control arm N: 108 Intervention arm N: 106 Diabetes type: unclear/not reported Mean age: NR ± NR % Male: NR Longest follow‐up: 12 months
Interventions	Control arm: 1) Facilitated relay of clinical information Intervention arm: 1) Case management 2) Team changes 3) Electronic patient registry 4) Patient education 5) Promotion of self‐management
Outcomes	1) HbA1c, mean % (SD) Control arm: pre 8.0 (1.9), post 7.8 (1.9) Intervention arm: pre 8.1 (2.0), post 7.3 (1.2) 2) SBP, mean mmHg (SD) Control arm: pre 132.0 (17.2), post 132.3 (17.4) Intervention arm: pre 136.0 (18.4), post 131.0 (18.2) 3) LDL, mean mg/dL (SD) Control arm: pre 109.0 (36.5), post 101.4 (36.6) Intervention arm: pre 106.5 (35.3), post 91.9 (36.7)
Funding source	Supported by grants (MH041739 and MH069741) from the Services Division of the National Institute of Mental Health (to Dr. Katon) and by institutional support from Group Health Cooperative
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: " …use of a permuted‐block design, with randomly selected block sizes of 4, 6, and 8 patients" but how they generated this list is not reported.
Allocation concealment (selection bias)	Unclear risk	Not described.
Patient's baseline characteristics (selection bias)	Unclear risk	Mentioned in text, but not in table.
Patient's baseline outcomes (selection bias)	Low risk	Quote: "The characteristics of the patients in the intervention group and the usual‐care group were similar at baseline."
Incomplete outcome data (attrition bias)	High risk	Numbers and reasons for loss to follow‐up not provided; they only provide the percentage who completed 6 months and 12 months follow‐up. Baseline based on those randomised, however seems like a per‐protocol analysis was done.
Blinding of participants and personnel (performance bias) and of outcome assessors (detection bias)	Low risk	Primary outcomes: laboratory methods not described, however they state that research assistants who carried out the study protocol were blinded; assume they were the outcome assessors. However, physicians were not blinded, had both intervention and comparator as patients, and could have influenced the treatment.
Selective reporting (reporting bias)	Low risk	Checked protocol and everything proposed was completed.
Risk of contamination (other bias)	High risk	Quote: "Spillover of the intervention is possible, since primary care physicians cared for patients in both the intervention and control groups."
Other bias	Low risk	Information not available.