Advance telephone notification of follow-up in the healthlines study: a nested study of patients with depression

Abstract

Background: Advance notification may increase response to follow‐up questionnaires among trial participants, but the benefit of this resourceintensive activity remains uncertain. This study investigated the effectiveness of pre‐calling participants with depression ahead of followup in The Healthlines Study, a trial of a telehealth intervention. Methods: Participants in one of the three study centres were alternately allocated to either be telephoned 2‐7 days before sending an 8‐month follow‐up questionnaire by post or email, or to be sent the questionnaire without pre‐calling. All participants received up to five questionnaire completion reminders. The primary outcome was completion of the PHQ‐9 outcome. Secondary outcomes were number of reminders and time to questionnaire completion. Results: 201 participants were included in the nested study (100 to precalling), of a total of 609 in the Healthlines depression trial. Outcome completion was ≥90% in both arms (OR 0.82, 95% CI 0.31 to 2.19). Participants in the pre‐calling arm were less likely to require a reminder (47% vs 62%, OR 0.46, 0.25 to 0.84), required fewer reminders (difference in means ‐0.6, ‐1.1 to ‐0.2), and completed follow‐up quicker (median 8 vs 15 days, HR 1.24, 0.92 to 1.66) than participants who received no precalling. Conclusion: Outcome completion rate at 8‐months follow‐up was high. There was no evidence that pre‐calling participants achieved better completion rates, nor reduced overall net effort required to achieve follow‐up after taking into account pre‐contacting these participants. Precalling may be helpful when timing of outcome completion is important.