Investigation of bias due to loss of participants in a Dutch multicentre prospective spinal cord injury cohort study.
OBJECTIVE
To determine bias due to loss of participants (attrition bias) in a prospective cohort study.


METHODS
A multi-centre prospective cohort study.


METHODS
A total of 225 individuals with a spinal cord injury from 8 Dutch rehabilitation centres.


METHODS
Participants were considered non-participants when no information was collected at the measurement one year after discharge from inpatient rehabilitation. Using bivariate tests participants and non-participants were compared regarding personal, lesion, function and functional characteristics determined at the beginning of inpatient rehabilitation and at discharge. A logistic regression was performed to determine which characteristics predict participation at one year after discharge.


RESULTS
Of the participants at the start of the study, 31% (n = 69) did not perform the tests one year after discharge from inpatient rehabilitation. Variables associated with study participation one year after discharge were: higher level of education, higher well-being score at the start of rehabilitation, and a shorter length of stay in hospital and rehabilitation centre at discharge of inpatient rehabilitation.


CONCLUSIONS
Selective attrition in the longitudinal study might have led to an over-estimation of some of the results of the measurement one year after discharge from inpatient rehabilitation.
Rehabilitation Centre Amsterdam, Overtoom 283, Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit Amsterdam. s.de.groot@fbw.vu.nl
Sonja
S
de Groot
Janneke A
JA
Haisma
Marcel W M
MW
Post
Floris W A
FW
van Asbeck
Lucas H V
LH
van der Woude
D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000368:Aged; D015982:Bias; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010352:Patient Dropouts / Q000706:statistics & numerical data; D010358:Patient Participation / Q000706:statistics & numerical data; D011446:Prospective Studies; D013119:Spinal Cord Injuries / Q000534:rehabilitation*; D055815:Young Adult