Spencer 2011 African‐Amer.

Methods	Parallel randomised controlled clinical trial (RCT) Randomisation ratio: 9:11 (intervention:control) to account for attrition rate Superiority design
Participants	African American type 2 diabetics in certain ZIP codes of Detroit Inclusion criteria: At least 18 years of age Had physician‐diagnosed type 2 diabetes Self‐identified as African American or Hispanic/Hispanic Lived in targeted zip codes Exclusion criteria: Those who already had serious diabetes complications (e.g. blindness, amputated limbs, kidney failure) Diagnostic criteria: "physician diagnosed" Participating population: 164 Hispanic or African American residents of Detroit (70 Hispanic, 94 African American)
Interventions	Trained community health workers (CHWs) A.K.A. “family health advocates” promoted healthy lifestyle and self‐management activities. In addition, family health advocates helped participants improve their patient‐provider communication skills and facilitated necessary referrals to other service systems. This took the form of: 11 × 2‐hour local community group diabetes education classes 2 home visits of 60 minutes in length per month A phone call every 2 weeks 1 clinic visit accompanied by the family health advocate Participants in the control group were contacted once per month to update contact information
Outcomes	Primary: Serum HbA1c level at 6 months Secondary: (at baseline and at 6 months) Serum LDL level Systolic and diastolic BP BMI Knowledge—as measured by the question, “Do you understand how to manage your diabetes?” 1 = Not At All to 5 = Very Well (Fitzgerald et al, 1996) Problem Areas in Diabetes scale score—20 items, 0 = Not a Problem to 4 = Serious Problem, Cronbach’s alpha = .94 (Polanski 1995; Polanski 1996) Self‐efficacy (as measured by the Perceived Competence for Diabetes Scale)
Study details	Run‐in period: Recruitment of participants took place between September 2004 and July 2006 Study terminated before regular end: no
Publication details	Publication status: peer‐reviewed journal
Stated aim of study	To test "the effectiveness of a culturally tailored, behavioural theory‐based community health worker intervention for improving glycaemic control”
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote from publication: “Participants were stratified by race/ethnicity and health care site during randomisation to ensure that those variables were equally distributed across the 2 arms of the intervention” Comment: does not specify how exactly randomly assigned to intervention
Allocation concealment (selection bias)	Unclear risk	Comment: not commented on
Blinding of participants and personnel (performance bias) Objective outcomes	High risk	Quote from publication: "Participants, community health workers and interviewers were not blinded to the group assignment; however data analysts were blinded"
Blinding of participants and personnel (performance bias) Subjective outcomes	High risk	Comment: participants not blinded, and therefore may feel expected to overestimate the subjective outcomes to appear to have engaged with health workers (with whom they are likely to have formed relationships given the large amount of time input)
Blinding of outcome assessment (detection bias) Lab tests: Lipids, HBA1C	Low risk	Quote from publication: "Participants, community health workers and interviewers were not blinded to the group assignment; however data analysts were blinded" Comment: objective outcomes extracted from GP notes; therefore assumed to be independently collected
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Comment: interviewers not blinded. It is very possible that the tone of the interview could alter people's answers to subjective outcomes
Incomplete outcome data (attrition bias) Objective outcomes	Low risk	Comment: Details of participants lost to follow‐up are well documented and seem comparable between groups
Incomplete outcome data (attrition bias) Subjective outcomes	Low risk	Comment: Details of participants lost to follow‐up are well documented and seem comparable between groups
Selective reporting (reporting bias)	Unclear risk	Comment: All data are commented upon; however, study protocol not seen
Other bias	Unclear risk	Comment: none