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Table 2 Assessment of risk of bias of included studies

From: Telephone based self-management support by ‘lay health workers’ and ‘peer support workers’ to prevent and manage vascular diseases: a systematic review and meta-analysis

Study Random sequence (Judgment) Allocation concealment (Judgment) Blinding participants (Judgment) Blinding outcome (Judgment) Incomplete outcome (Judgment) Selective reporting (Judgment)
Turner 2012[27] Randomised using a random computer sequence generation (√) No information (?) Attempted blinding as ALL patients received mailed brochures about heart disease. Clinical outcomes (changes in 4 year CHD risk, systolic and diastolic blood pressure) assessors were blinded (√) 85% completed blood pressure assessment and 69% completed CHD risk assessment. No difference between groups. More withdrawals in intervention group (20/136 v 13/144). Multiple imputation for all missing values (√) No protocol, description of clinical assessments correspond to outcomes (X)
No self report outcomes (√)
Walker 2011[28] Randomised using a random computer sequence generation (√) No information (?) Attempted blinding as ALL patients received mailed brochures about heart disease. Self report outcomes used (X) No blinding (X) 87% completed outcomes assessments at 12 months. No difference between groups. More withdrawals in control group (3/264 v 2/262). Multiple imputation for all missing values (√) No protocol, description of clinical assessments correspond to outcomes (X)
Outcomes self-report by telephone. Physiological measures completed using the ‘dry-dot methodology’ involving patient mailing sample to the lab (?)
Heisler 2010[33] Randomised using a random sequence generation (√) Centrally (√) Blinded patients, research staff and care managers at baseline. Intervention was described as a comparison of 2 diabetes self-management support models to participants. Not clear after baseline (X) Only data assessors were blinded (X) 89% completed HbA1c assessments and 95% completed survey assessments, no differences between groups, justification is provided (√) No protocol, description of measures orresponds to outcomes (X)
Dale 2009[9] No details about sequence generation – states randomised only (?) Opaque sealed envelopes (X) Attempted blinding as ALL patients received one telephone call (X) Outcomes self report by post (?) 91% follow up at 6 months (93.3%, 86.4% and 91.8% overall) no reasons given (?) Protocol reported diabetes self care activities measure which was not reported in the main trial (X)
Physiological measures assessed blinded to group (√)
Samuel-Hodge 2009[32] Cluster randomised. Computer generated random number (√) Sequentially numbered sealed envelopes (X) No blinding, self report outcome (X) HbA1c measures masked to study group (√) 87% follow up at 8 months, 85% at 12 months, no difference between groups, more withdrawals in intervention group (6/102 v 1/72) (√) No protocol, insufficient information (?)
Physical activity not clear (?)
FFQ and other psychosocial outcomes by telephone, masked to study group but not clear if it could have been broken (?)
Parry 2009[34] Internet based randomisation service (√) Central (√) No blinding, self report outcome (X) Researchers blinded to group allocation, self reported outcomes, but not clear if could have been broken (?) Follow up 94% at 8 weeks, no difference between groups, reasons given (√) No protocol, insufficient information (?)
Batik 2008[30] Non random assignment of late new participants to control group (X) No information (?) No blinding, self report outcome (X) Outcomes self-report (?) No data reported on follow up (?) No protocol, insufficient information (?)
Physiological measures (?)
Carroll 2007[31] No details about sequence generation, states randomised only (?) No information (?) No blinding, self report outcome (X) Outcomes self-report via telephone (?) 18.6% attrition, no reasons given (?) No protocol, insufficient information (?)
Young 2005[35] Post-recruitment block randomisation, stratified by baseline HbA1c using SAS software (√) Randomise intervention to control in a ratio of 2:1 (√) No information (?) No information (?) 8.2% lost at follow-up, justification is provided, intention to treat analyses (√) No information (?)
Keyserling 2002[29] Randomised using random numbers generated using a personal computer (√) Consequently numbered sealed envelopes containing study group assignments (X) No blinding, self report outcome (X) Clinicians were informed of participants group assignment, no more information is provided (X) 88% and 84% of participants completed the 6th and 12th month follow-up, no differences between groups, justification is provided (√) Protocol includes self-care, but no outcomes are reported (X)
  1. Note: Judgment ratings:  = Low risk of bias; X = High risk of bias; ? = Unclear risk of bias [22].