Ell 2010.

Study characteristics
Methods	Collaborative care management of major depression among low‐income, predominantly Hispanic subjects with diabetes Patient RCT, conducted in 2 public safety net clinics, USA Two arms: 1. Enhanced usual care (control arm) and 2. Intervention group (intervention arm)
Participants	Control arm N: 194 Intervention arm N: 193 Diabetes type: type 1 and type 2 Mean age: NR ± NR % Male: NR Longest follow‐up: 18 months
Interventions	Control arm: 1) Patient education Intervention arm: 1) Case management 2) Team changes 3) Promotion of self‐management
Outcomes	1) HbA1c, mean % (SD) Control arm: pre 9.1 (2.2), post 8.5 (2.2) Intervention arm: pre 9.0 (2.2), post 8.3 (2.0)
Funding source	The study is supported by R01 MH068468 from the National Institute of Mental Health (principal investigator, K.E.)
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was conducted via a computer‐generated random number in blocks of 10…"
Allocation concealment (selection bias)	Unclear risk	Quote: "…with random assignment number enclosed in sealed envelopes: patients selected one of five sequential envelopes following baseline interviews." Opaque envelopes?
Patient's baseline characteristics (selection bias)	High risk	P ≤ 0.05: living in USA (years), Spanish speaking, socioeconomic stress, Whitty‐9 diabetes symptoms, chronic pain, pain medications, depression, dysthymic disorder, history of major depression
Patient's baseline outcomes (selection bias)	Low risk	HbA1c: P = 0.98
Incomplete outcome data (attrition bias)	High risk	~30% lost to follow‐up in control; ~25% lost to follow‐up in intervention, reasons seems balanced.
Blinding of participants and personnel (performance bias) and of outcome assessors (detection bias)	Unclear risk	Primary outcome was the 20‐item symptom checklist. Unclear if outcome assessor was blinded. Primary outcome was also Hba1c: derived from medical records.
Selective reporting (reporting bias)	Low risk	Information not available.
Risk of contamination (other bias)	High risk	Quote: "Because the same practitioners treated both intervention and Enhanced Usual Care (EUC) patients, there may have also been a spillover effect on quality of depression treatment."
Other bias	Low risk	Information not available.