Nuttall 2003

Methods	Purpose: test hypothesis that an invitation letter to attend GP for influenza immunisation plus home visit to discuss influenza vaccination is more likely to increase influenza vaccine uptake than an invitation letter to attend GP for immunisation alone, or invitation letter plus pamphlet promoting influenza immunisation Design: RCT: eligible participants were stratified by age (< 72 years; 72 years or older to ensure equal numbers each age group within each intervention group). Within each age group randomly allocated into 3 groups. A total of 30 persons were allocated to each intervention Interval between intervention and when outcome was measured: not explicitly stated: intervention was to be completed the start of the influenza immunisation programme at the GP surgery; health records audited "following completion of the influenza immunization program." Power computation: not done Statistics: simple comparison of proportions immunised across groups (ITT)
Participants	Country: UK Setting: a single GP practice in East Lancashire Eligible participants (health status): 90 participants aged 65 to 90 years registered to the practice who had failed to attend for the influenza immunisation prior year (i.e. 2000 to 2001 campaign (N = 393) who agreed to participate, were not confused, did not have egg allergy (i.e. 90 participants) Age:  50% were aged 65 to 72 years, 50% were aged over 72 years Gender: no information provided
Interventions	Intervention 1: invitation letter to attend GP for influenza immunisation plus leaflet promoting influenza vaccination Intervention 2: letter plus home visit Control: letter alone
Outcomes	Outcome measured: % vaccinated based upon audit of health records Time points from the study that are considered in the review or measured or reported in the study: research project started following ethical approval (received 2 August 2001) and was completed by June 2002 % vaccinated by: not explicitly stated
Notes	No source of funding mentioned Author comments that a smaller proportion of those immunised at outcome had received a prior vaccination, but a larger proportion of those immunised at outcome had a qualifying health condition at baseline 90 participants were eligible and consented of 393 who had failed to attend for the influenza immunisation prior year
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The 90 respondents were divided in half by age (< 72 years, 72 years or older). The participants in each age group were allocated into the 3 intervention groups, using the stratified randomisation technique
Allocation concealment (selection bias)	Unclear risk	No information provided
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No information provided
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition of participants? Implied to be none, not explicitly stated Incomplete data points for participants? No Analysis if differential attrition could affect outcomes? No information provided Vaccination data assessed by chart review (RCT was of a single practice)
Selective reporting (reporting bias)	Low risk	No selective reporting