title: Increasing follow-up questionnaire response rates in a randomized controlled trial of telehealth for depression: three embedded controlled studies.
abstract: BACKGROUND
  Attrition is problematic in trials, and may be exacerbated in longer studies, telehealth trials and participants with depression - three features of The Healthlines Study. Advance notification, including a photograph and using action-oriented email subject lines might increase response rates, but require further investigation. We examined the effectiveness of these interventions in three embedded Healthlines studies.
  
  
  METHODS
  Based in different trial sites, participants with depression were alternately allocated to be pre-called or not ahead of the 8-month follow-up questionnaire (Study 1), randomized to receive a research team photograph or not with their 12-month questionnaire (Study 2), and randomized to receive an action-oriented ('ACTION REQUIRED') or standard ('Questionnaire reminder') 12-month email reminder (Study 3). Participants could complete online or postal questionnaires, and received up to five questionnaire reminders. The primary outcome was completion of the Patient Health Questionnaire (PHQ-9). Secondary outcome measures were the number of reminders and time to questionnaire completion.
  
  
  RESULTS
  Of a total of 609 Healthlines depression participants, 190, 251 and 231 participants were included in Studies 1-3 (intervention: 95, 126 and 115), respectively. Outcome completion was ≥90 % across studies, with no differences between trial arms (Study 1: OR 0.38, 95 % CI 0.07-2.10; Study 2: OR 0.84, 95 % CI 0.26-2.66; Study 3: OR 0.53 95 % CI 0.19-1.49). Pre-called participants were less likely to require a reminder (48.4 % vs 62.1 %, OR 0.41, 95 % CI 0.21-0.78), required fewer reminders (adjusted difference in means -0.67, 95 % CI -1.13 to -0.20), and completed follow-up quicker (median 8 vs 15 days, HR 1.35, 95 % CI 1.00-1.82) than control subjects. There were no significant between-group differences in Studies 2 or 3.
  
  
  CONCLUSIONS
  Eventual response rates in this trial were high, with no further improvement from these interventions. While the photograph and email interventions were ineffective, pre-calling participants reduced time to completion. This strategy might be helpful when the timing of study completion is important. Researchers perceived a substantial benefit from the reduction in reminders with pre-calling, despite no overall decrease in net effort after accounting for pre-notification.
  
  
  BACKGROUND
  Current Clinical Trials ISRCTN14172341.
authors.affiliation: Centre for Academic Primary Care, School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. louisa.edwards@bristol.ac.uk.
authors.forename: Louisa
authors.initials: L
authors.lastname: Edwards
authors.affiliation: Centre for Academic Primary Care, School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. c.salisbury@bristol.ac.uk.
authors.forename: Chris
authors.initials: C
authors.lastname: Salisbury
authors.affiliation: School of Health and Related Research (ScHARR), University of Sheffield, Regent Court, 30 Regent Street, Sheffield, S1 4DA, UK. k.horspool@sheffield.ac.uk.
authors.forename: Kimberley
authors.initials: K
authors.lastname: Horspool
authors.affiliation: School of Health and Related Research (ScHARR), University of Sheffield, Regent Court, 30 Regent Street, Sheffield, S1 4DA, UK. alexis.foster@sheffield.ac.uk.
authors.forename: Alexis
authors.initials: A
authors.lastname: Foster
authors.affiliation: Centre for Academic Primary Care, School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. katy.garner@bristol.ac.uk.
authors.forename: Katy
authors.initials: K
authors.lastname: Garner
authors.affiliation: Nottingham Clinical Trials Unit, The University of Nottingham, C Floor, South Block, Queen's Medical Centre, Nottingham, NG7 2UH, UK. alan.montgomery@nottingham.ac.uk.
authors.forename: Alan A
authors.initials: AA
authors.lastname: Montgomery
mesh_terms: D000328:Adult; D003863:Depression / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D034742:Electronic Mail; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D010352:Patient Dropouts; D010781:Photography; D011177:Postal Service; D017010:Reminder Systems; D035842:Research Subjects / Q000523:psychology*; D011795:Surveys and Questionnaires; D017216:Telemedicine / Q000379:methods*; D013689:Telephone; D013997:Time Factors; D016896:Treatment Outcome; D006113:United Kingdom