Butler 1996.

Methods	Randomised parallel group trial.
Participants	80 participants aged 17‐85 years (mean 63, SD 13) undergoing total hip replacement. Intervention group: 18 women, 14 men (mean age 64 years, SD 13); control group: 22 women, 26 men (mean age 62 years, SD 13). Inclusion criteria: ability to read English. Exclusion criteria: previous hip replacement. Location: Canada.
Interventions	Intervention group (n = 32) posted an 18‐page teaching booklet as part of the pre‐admission package 4‐6 weeks before surgery. Control group (n = 48) posted pre‐admission package only (containing information of a general nature).
Outcomes	Anxiety (Spielberger State‐Trait Anxiety Inventory (20‐80 points) higher score represented greater anxiety); length of hospital stay; practising of pre‐hospital preparatory exercises; attendance at physiotherapy and occupational therapy sessions; participant satisfaction. Participants were assessed pre‐ and post‐intervention.
Notes	On admission, both groups were treated identically. Patient satisfaction ratings were only taken just before discharge, by which time both groups had received the same information. An overall satisfaction rating was not obtained. Instead, ratings were given for each of six questions. The data entered in the review for patient satisfaction relate to the question "How satisfied were you with the amount of information you received about your hip joint and what a total hip replacement is?".
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: sequence generation not described.
Allocation concealment (selection bias)	Low risk	Quote: "A patient guide booklet was randomly added to half of the preadmission packages mailed out to THR [total hip replacement] patients." Comment: random allocation of the patient guide booklet was done by a clerk in the Admissions Department (and was concealed from the trial investigators) ‐ personal communication with author.
Blinding (performance bias and detection bias) Self‐reported outcomes	High risk	Comment: patients were not aware of the trial when booklets were randomly added to half the packages mailed out. Only at admission were patients informed of the purpose of the trial, gave their consent and then completed the anxiety inventory. Knowledge of the intervention could have influenced responses, especially those relating to anxiety and satisfaction with information.
Blinding (performance bias and detection bias) Objective outcomes	Unclear risk	Comment: unclear if trial personnel were blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote: "Eight additional patients were excluded because they were discharged before their predischarge data could be collected." Comment: not clear if these 8 participants were undergoing hip replacement for the first time (and thus would have been included in the analysis). There were missing data for all outcomes (in addition to the 8 participants mentioned above) ranging from 2 to 12 participants (length of stay). The reasons for drop‐outs are not stated.
Selective reporting (reporting bias)	Unclear risk	Comment: outcomes stated in the methods were reported in the results. Outcome data for satisfaction were not reported in sufficient detail in the paper but were provided by the study author on request. Without the trial protocol, it is unclear whether any other outcomes were measured but not reported based on the results.
Other bias	Low risk	Comment: no other sources of bias identified.