Reproducibility and validity of the Dutch translation of the de Morton Mobility Index (DEMMI) used by physiotherapists in older patients with knee or hip osteoarthritis.
OBJECTIVE
To examine the reproducibility, construct validity, and unidimensionality of the Dutch translation of the de Morton Mobility Index (DEMMI), a performance-based measure of mobility for older patients.


METHODS
Cross-sectional study.


METHODS
Rehabilitation center (reproducibility study) and hospital (validity study).


METHODS
Patients (N=28; age >65y) after orthopedic surgery (reproducibility study) and patients (N=219; age >65y) waiting for total hip or total knee arthroplasty (validity study).


METHODS
Not applicable.


METHODS
Not applicable.


RESULTS
The intraclass correlation coefficient for interrater reliability was high (.85; 95% confidence interval, 71-.93), and minimal detectable change with 90% confidence was 7 on the 100-point DEMMI scale. Rasch analysis identified that the Dutch translation of the DEMMI is a unidimensional measure of mobility in this population. DEMMI scores showed high correlations with scores on other performance-based measures of mobility (Timed Up and Go test, Spearman r=-.73; Chair Rise Time, r=-.69; walking test, r=.74). A lower correlation of .44 was identified with the self-report measure Western Ontario and McMaster Universities Osteoarthritis Index.


CONCLUSIONS
The Dutch translation of the DEMMI is a reproducible and valid performance-based measure for assessing mobility in older patients with knee or hip osteoarthritis.
TNO Healthy Living, Leiden, The Netherlands. marielle.jans@hu.nl
Marielle P
MP
Jans
Vera C
VC
Slootweg
Cecile R
CR
Boot
Natalie A
NA
de Morton
Geert
G
van der Sluis
Nico L
NL
van Meeteren
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands; D015588:Observer Variation; D015207:Osteoarthritis, Hip / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D026741:Physical Therapy Modalities; D015203:Reproducibility of Results; D014175:Translating