Review of retention strategies in longitudinal studies and application to follow-up of ICU survivors.
OBJECTIVE
To review the literature on retention strategies in follow-up studies and their relevance to critical care and to comment on the Toronto experience with the acute respiratory distress syndrome (ARDS) and severe acute respiratory syndrome (SARS) follow-up studies.


METHODS
Literature review and two cohort studies in a tertiary care hospital in Toronto, Canada.


METHODS
ARDS and SARS patients.


RESULTS
Review articles from the social sciences and medicine are summarized and our own experience with two longitudinal studies is drawn upon to elucidate strategies that can be successfully used to attenuate participant drop-out from longitudinal studies. Three key areas for retention of subjects are identified from the literature: (a) respect for patients: respect for their ideas and their time commitment to the research project; (b) tracking: collect information on many patient contacts at the initiation of the study and outline tracking procedures for subjects lost to follow-up; and (c) study personnel: interpersonal skills must be reinforced, flexible working hours mandated, and support offered. Our 5-year ARDS and 1-year SARS study retention rates were 86% and 91%, respectively, using these methods.


CONCLUSIONS
Strategies to reduce patient attrition are time consuming but necessary to preserve internal and external validity. When the follow-up system is working effectively, researchers can acquire the necessary data to advance knowledge in their field and patients are satisfied that they have an important role to play in the research project.
Tansey
Catherine M
CM
Department of Medicine, Toronto General Hospital, University Health Network, 585 University Ave, ON M5G 2N2, Toronto, Canada. catherine.tansey@utoronto.ca
Matté
Andrea L
AL
Needham
Dale
D
Herridge
Margaret S
MS
D006801:Humans; D007362:Intensive Care Units; D008137:Longitudinal Studies; D009864:Ontario; D010352:Patient Dropouts; D010358:Patient Participation; D017741:Survivors
J Nurs Scholarsh. 2002;34(1):47-53
11901967
N Engl J Med. 2003 Feb 20;348(8):683-93
12594312
Control Clin Trials. 1997 Oct;18(5):383-96
9315423
Am J Respir Crit Care Med. 2006 Sep 1;174(5):538-44
16763220
Crit Care Med. 2004 May;32(5 Suppl):S209-13
15118519
Can J Nurs Res. 2004 Sep;36(3):82-98
15551664
Int J Epidemiol. 2004 Jun;33(3):493-8
15131086
Drug Alcohol Depend. 1996 Jul;41(3):209-17
8842633
J Adolesc. 2003 Jun;26(3):363-73
12770532
Arch Intern Med. 2007 Jun 25;167(12):1312-20
17592106
Subst Use Misuse. 1998 Nov;33(13):2665-85
9818993
Epidemiol Rev. 1998;20(1):57-70
9762509
Health Technol Assess. 2000;4(24):1-111
11074394
J Subst Abuse Treat. 1995 Mar-Apr;12(2):95-102
7623396