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.
de Groot
Sonja
S
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
Haisma
Janneke A
JA
Post
Marcel W M
MW
van Asbeck
Floris W A
FW
van der Woude
Lucas H V
LH
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