Psychometric characteristics of the Brazilian-Portuguese versions of the Functional Rating Index and the Roland Morris Disability Questionnaire.
METHODS
Translation, cross-cultural adaptation and psychometric testing of self-report outcome measurements.


OBJECTIVE
The aims of this study were to adapt the Functional Rating Index (FRI) to Brazilian-Portuguese and to test the psychometric properties of this new questionnaire and the Brazilian-Roland Morris Disability Questionnaire (RMDQ).


BACKGROUND
Self-report measures are commonly used in clinical practice and in research studies. Most existing questionnaires were developed in English and there is only 1 Brazilian-Portuguese cross-cultural adaptation of a spine outcome measure.


METHODS
The FRI was translated and adapted into Brazilian-Portuguese according to the Guidelines for the process of cross-cultural adaptation of self report measures. The Brazilian-Portuguese FRI and RMDQ were tested for internal consistency, reliability, ceiling and floor effects, construct validity, and responsiveness in 140 low back pain (LBP) patients.


RESULTS
A very high level of internal consistency (Cronbach's alpha = 0.92) and reliability [ICC = 0.95 (95% confidence interval, 0.93-0.97)] was shown for both instruments. The FRI and RMDQ were highly correlated (r = 0.80), while both the FRI and RMDQ were moderately correlated with pain at baseline (r = 0.67 and 0.55, respectively). No ceiling or floor effects were detected; however, the responsiveness of both questionnaires was quite small (RMDQ ES = 0.10 [84% confidence interval, 0.04-0.16] and FRI ES = 0.18 [84% confidence interval, 0.11-0.24]).


CONCLUSIONS
The results of this study indicate that the Brazilian-Portuguese versions of the FRI and RMDQ are reliable and valid instruments for the measurement of disability in Brazilian-Portuguese-speaking patients with LBP presenting for physiotherapy treatment. Both instruments are suitable for use in clinical practice and research studies.
Costa
Leonardo Oliveira Pena
LO
Back Pain Research Group, School of Physiotherapy, University of Sydney, Lidcombe NSW, Australia. lcos3060@usyd.edu.au
Maher
Chris G
CG
Latimer
Jane
J
Ferreira
Paulo Henrique
PH
Pozzi
Giovanni Campos
GC
Ribeiro
Rodrigo Nogueira
RN
D000328:Adult; D001938:Brazil; D032882:Comprehension; D003431:Cross-Cultural Comparison; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007802:Language; D017116:Low Back Pain / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D026741:Physical Therapy Modalities; D011174:Portugal; D011594:Psychometrics; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires