Mixed-mode versus paper surveys for patient-reported outcomes after critical illness: A randomised controlled trial.

Objective: The aim of the study was to determine the response rate to a mixed-mode survey using email compared with that to a paper survey in survivors of critical illness.
Design: This is a prospective randomised controlled trial.
Setting: The study was conducted at a single-centre quaternary intensive care unit (ICU) in Adelaide, Australia.
Participants: Study participants were patients admitted to the ICU for ≥48 h and discharged from the hospital.
Interventions: The participants were randomised to receive a survey by paper (via mail) or via online (via email, or if a non-email user, via a letter with a website address). Patients who did not respond to the initial survey received a reminder paper survey after 14 days. The survey included quality of life (EuroQol-5D-5L), anxiety and depression (Hospital Anxiety and Depression Scale), and post-traumatic symptom (Impact of Event Scale-Revised) assessment.
Main Outcome Measures: Survey response rate, extent of survey completion, clinical outcomes at different time points after discharge, and survey cost analysis were the main outcome measures. Outcomes were stratified based on follow-up time after ICU discharge (3, 6, and 12 months).
Results: A total of 239 patients were randomised. The response rate was similar between the groups (mixed-mode: 78% [92/118 patients] vs. paper: 80% [97/121 patients], p = 0.751) and did not differ between time points of follow-up. Incomplete surveys were more prevalent in the paper group (10% vs 18%). The median EuroQol-5D-5L index value was 0.83 [0.71-0.92]. Depressive symptoms were reported by 25% of patients (46/187), anxiety symptoms were reported by 27% (50/187), and probable post-traumatic stress disorder was reported by 14% (25/184). Patient outcomes did not differ between the groups or time points of follow-up. The cost per reply was AU$ 16.60 (mixed-mode) vs AU$ 19.78 (paper).
Conclusion: The response rate of a mixed-mode survey is similar to that of a paper survey and may provide modest cost savings.
Competing Interests: Conflict of interest None.
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