McDowell 1986

Methods	Purpose: to compare reminders to receive influenza vaccination by telephone reminder by physician, telephone by nurse, or by letter Design: cluster‐RCT, participants randomised by family Duration of study: 23 October to 31 December 1984 Interval between intervention and when outcome was measured: 23 October to 31 December 1984 Power computation: sample sizes offered power to detect 10% to 15% difference in proportions (alpha not stated) Statistics: Chi2
Participants	Country: Canada Setting: Ottawa Civic Hospital Family Practice Clinics Eligible participants: (health status); 13,345 eligible patients, of whom 1420 > 65; 2 physicians refused to participate, leaving 939 participants; 113 had been vaccinated before the trial and were excluded; leaving 201 available for a personal reminder by physician, 208 for a phone call by nurse, 239 for a letter and 215 in a randomised control group Age: > 65 Gender: not stated Intervention group 1 (physician reminder): 1122 families, 1471 people Intervention group 2 (telephone reminder group): 1104 families, 1468 people Intervention group 3 (letter reminder group): 1168 families, 1541 people Control group: 1056 families, 1403 people eligible participants Exclusions: not clear
Interventions	Intervention 1 (physician reminder): a computer‐generated reminder was included on the routinely printed encounter form before any visit to the office to remind the physician of outstanding preventive procedures Intervention 2 (telephone reminder): the practice nurse attempted to contact the family, making a maximum of 5 calls during working hours, and completed an action form for each listed patient. Once contact was made the nurse advised the patient about the indicated procedures and then attempted to arrange for them to be performed. The person answering the telephone was asked to relay the message to other family members Intervention 3 (letter reminder): computer‐generated letter, signed by their physician and nurse, describing the procedures that were overdue for each member of the family and the importance of having them performed. After 21 days a second reminder was sent out to non‐respondents Control: no action was taken to remind the physicians or the participants that a procedure was overdue. Non‐randomised control group: the participants of 2 doctors who refused were not randomised and were treated as a second control group to assess the effects of the increased preventive activity in the practices In the 1990 article in Family Medicine, McDowell provided baseline vaccination data for the 1984, year before the 2‐year intervention in 1985 and 1986, and grouped the letter, nurse and physician reminders into one treatment group compared to a control, and we have followed this reporting of the results in the final publication in their series
Outcomes	Outcome measured: % vaccinated by 31 December 1984, recorded in clinic computer  Time points from the study that are considered in the review or measured or reported in the study: intervention 23 October 1984 to 31 December 1984, vaccine receipt assessed until 31 December 1984 % vaccinated by: 31 December 1984 Intervention 1 (physician reminder): 766/1471 persons visited the practice in the study year; 22.9% of group were vaccinated but the denominator for this proportion is not stated (i.e. cannot tell if it was 766 persons versus 1471 persons versus 1122 families) Intervention 2 (telephone reminder): 1104 of the 1468 families assigned to telephone required a reminder for one or more interventions and 684 families were actually contacted. 37% of group were vaccinated but denominator for proportion not stated (i.e. cannot tell if it was 1104 families versus 684 families versus 1468 persons that comprised the 1104 families versus unknown number of persons in the 684 families actually reached)  Intervention 3 (letter reminder): 164 of 1442 persons sent letters had letters returned as not deliverable. 35.2% were vaccinated but cannot tell which denominator was used (i.e. 1442 versus 978 persons) Control: 9.8% "of study group" were vaccinated. Not stated if the denominator is families or individual persons
Notes	Funding: Dept National Health and Welfare, Ontario Ministry of Health, Career Health Scientist Award to Dr. McDowell; follow‐up in 1985 showed no difference between intervention and control groups (McDowell 1990)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"... participants were randomly allocated by family"
Allocation concealment (selection bias)	Unclear risk	No statement
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No statement about blinding, but vaccinations recorded in clinic computer
Incomplete outcome data (attrition bias) All outcomes	High risk	Of 239 letters sent only 2 returned; nurses unable to contact 31 (15%) by phone Intervention 1: 766/1471 persons visited the practice in the study year; 22.9% of group vaccinated but the denominator for this proportion is not stated (cannot tell if it was 766 persons versus 1471 persons versus 1122 families) Intervention 2: 1104 of the 1468 families assigned to telephone required a reminder for 1 or more interventions and 684 families were actually contacted; 37% of group were vaccinated but denominator for proportion not stated (cannot tell if it was 1104 families versus 684 families versus 1468 persons that comprised the 1104 families versus unknown number of persons in the 684 families actually reached)  Intervention 3: 164 of 1442 persons sent letters had letters returned as not deliverable; 35.2% were vaccinated but cannot tell which denominator was used (1442 versus 978 persons) Control: 9.8% "of study group" were vaccinated. Not stated if the denominator is families or individual persons "8 weeks after the study ended we called random samples of patients from each study group who had apparently not ben vaccinated to estimate the extent of underreporting."
Selective reporting (reporting bias)	Low risk	No selective reporting