Maglione 2002a

Methods	Purpose: to compare a letter and brochure to no intervention in Minnesota. Other interventions were a postcard compared to no intervention (Utah‐Nevada Maglione 2002c), a letter plus postcard compared to no intervention (Washington State, Maglione 2002d), and a letter to a postcard compared to a letter and postcard and to no intervention (New Jersey, Maglione 2002b) Design: RCT; Peer Review Organizations in US states are required to conduct quality improvement projects and report results as part of the Health Care Quality Improvement Project (HCQIP). Maglione 2002a searched the HCQIP database for these reports, and identified published reports about Montana (McMahon 1995a) and Wyoming (McMahon 1995b) and unpublished reports about Minnesota, Utah‐Nevada, New Jersey and Washington State. Authors independently abstracted, compared and resolved discrepancies in data for study design, number and characteristics of patients, setting. Location and target of intervention, time from intervention to outcome measurement and results Duration of study: not stated (McMahon 1995a and McMahon 1995b were 3 months) Interval between intervention and when outcome was measured: brochure or letter mailed: not stated. All 4 unpublished RCTs were reported as being performed in 1996 Power computation: not performed Statistics: percentages
Participants	Total number: Minnesota (letter plus brochure 2924; no intervention 3343); Utah‐Nevada (postcard 25,000, no intervention 50,437); Washington State (letter plus postcard 16,082, no intervention 16,057); New Jersey (letter 16,000, postcard 16,001, letter plus postcard 16,000, no intervention 16,001) Setting: Minnesota, Utah‐Nevada, Washington State, New Jersey, all Medicare Part B beneficiaries Diagnostic criteria: % receiving influenza vaccination, validated by HCFA billing claims Gender: not stated Age: ≥ 65 Country: USA [Co‐morbidity not stated] [Socio‐demographics not stated] [Ethnicity not stated] [Date of studies 1996]
Interventions	Intervention 1: letter Intervention 2: postcard Intervention 3: brochure Control: no intervention [Integrity of intervention: not stated]
Outcomes	Outcome measured: % vaccinated as measured by HCFA billing claims Time points from the study that are considered in the review or measured or reported in the study: 1996 % vaccinated during 1996
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described only as "RCT"
Allocation concealment (selection bias)	Unclear risk	No statement
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No statement
Incomplete outcome data (attrition bias) All outcomes	Low risk	96% of those ≥ 65 are covered by Medicare Part B, which processes all billing claims for influenza vaccination
Selective reporting (reporting bias)	Low risk	No selective reporting