Dietrich 2004.

Methods	Study design: Cluster‐randomised controlled trial
Participants	Setting: Primary care Diagnosis: Meeting criteria for Diagnostic and Statistical Manual of Mental Disorders fourth edition for major depressive disorder and dysthymia. Diagnosis determined using a structured interview. The severity of depression was assessed with the Hopkins symptom checklist‐20, with a score of 0.5 or more required for enrolment. Inclusion criteria: 18 years or older and starting or changing treatment for depression. Participants had to have a telephone and speak English Exclusion criteria: Being unobtainable for an evaluation interview within 14 days of their index primary care visit, pregnant, suicidal thoughts, schizophrenia, bipolar disorder, post‐traumatic stress disorder, or a substance misuse disorder. Age: Mean 42 years Gender: 80% female Ethnicity: 17% ethnic minority Country: United States Sample size (randomised): Total clusters 60, intervention 32, control 28; Total participants 405, intervention 224, control 181
Interventions	Intervention: Quality improvement programme Contains the four elements of collaborative care: 1) a multi‐professional approach to patient care: Primary care clinicians (PCP), primary care or mental health nurses (CM), psychiatrist (MH specialist) 2) a structured management plan: A systematic approach to the assessment and management of depression by PCPs which involved CMs assisting patients in overcoming barriers to adherence to the management plan and supporting self‐management practices such as exercise or engaging in social activities. 3) scheduled patient follow‐ups: One week after initial visit and monthly thereafter until remission. 4) enhanced inter‐professional communication: PCPs received faxed report about patient progress and care management actions after each call. MH specialists provided suggestions for clinical management to PCPs either via CM faxes or by telephone. PCPs can also request advice from MH specialist at specified times in the week. Control: Treatment as usual enhanced as clinicians took part in a 45‐60 minute programme on diagnosis of depression and assessment of suicidal thoughts.
Outcomes	Depression (HSCL‐20): 3, 6 months Medication use: 3, 6 months Satisfaction: 3, 6 months
Notes	CM: case manager; HSCL: Hopkins Sympton Checklist; MH: mental health; PCP: primary care provider
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Coin‐toss
Allocation concealment (selection bias)	Unclear risk	Central randomisation of clinic, those recruiting patients may have been aware of allocation
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Short‐term loss to follow‐up based on primary depression outcome (HSCL‐20) was: overall 80/405 (20%), 45/224 (20%) intervention and 35/181 (19%) control. Reasons for loss to follow‐up not provided. Used intention‐to‐treat analysis
Selective reporting (reporting bias)	Low risk	Protocol available and all prespecified outcomes reported
Other bias	Unclear risk	Insufficient information available to assess
Implementation Integrity	Unclear risk	Insufficient information available to assess
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel could not be blinded, outcome likely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Assessor was not aware of treatment allocation