Puech 1998

Methods	Purpose: to determine if a single postcard reminder for participants aged 65 years or older would improve influenza vaccination uptake in a 3‐partner general practice Design: RCT Duration of study: 1 April to 31 July 1996 Interval between intervention and when outcome was measured: postcard mailed on 1 April 1996. Outcomes ascertained "end of July 1996" ‐ 4 months later Power computation: study power to detect a difference of 20% in immunisation rates at 0.05 (2 sided): 61% for males, 81% for females Statistics: randomisation was done within sex strata, analysis controlled (logistic regression) for 1995 immunisation status and study factor but did not control for proximity to practice. Separate regressions done for males and females
Participants	Country: Australia Site: Leichhardt general practice (a 3‐partner practice) in suburban Sydney, Australia Eligible participants: 325 participants aged 65 years or older identified from a computerised age‐sex‐disease registry maintained by the general practice who had made at least 3 visits to the practice, one of which had to have occurred in the 2 years prior to study Age: 65 to 69 years: 86/325 (26.5%) 70 to 74 years: 78/325 (24.0%) 75 to 79 years: 58/325 (17.8%) 80 to 84 years: 62/325 (19.1%) 85 years or older: 41/325 (12.6%) Gender: 38.5% male, 61.5% female Exclusions: 1) Nursing home residents were excluded as not on the computerised register; 2) flu vaccination received prior to 1 April 1996; 3) participants who had left practice, gone to a nursing home or died since most recent update of the practice register, 4) those known to be allergic to egg protein, 5) known by practice to object to flu vaccination, or having severe or terminal illness, dementia or unstable psychiatric conditions
Interventions	Intervention 1: postcard mailed 1 April 1996 reminding them to attend the practice for an influenza vaccination before the end of the month and providing information on disease and vaccine, vaccine availability and vaccine cost Control: usual care: "ad hoc approach" co‐interventions: "influenced by news coverage of outbreaks, media campaigns by vaccine manufacturers, opportunistic reminders and secular events"
Outcomes	Outcome measured: % vaccinated in 1996 (end of July) as validated by chart review Time points from the study that are considered in the review or measured or reported in the study: postcards mailed to intervention group on 1 April 1996. Practice records reviewed for documentation of receiving vaccination at the end of July 1996
Notes	Chart review of practice: assessor blind to patient group allocation; required documentation in chart that vaccination, not just prescription for vaccine actually provided. However, no information provided as to whether or not chart review would have captured any vaccinations obtained from outside of the practice Funding: no information provided
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants stratified by sex, then computer‐generated random numbers; however for married couples once identified as married, both randomly allocated to same intervention
Allocation concealment (selection bias)	Unclear risk	Insufficient information
Blinding (performance bias and detection bias) All outcomes	Low risk	General practitioners were blind to allocation but no information provided on methods of blinding. Person who assessed outcome was blind to the patient group allocation
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Outcomes were ascertained from patient chart and participants were considered immunised if either immunisation documented in patient record OR a prescription given for flu vaccine but no record of the actual vaccination in the notes. Authors provide no information on loss to follow‐up, thus it is possible that persons recorded as not vaccinated might in theory have received it from another practice
Selective reporting (reporting bias)	Low risk	No selective reporting