Reliability, validity, interpretability and responsiveness of the DEMMI mobility index for Brazilian older hospitalized patients.

Aim To translate and adapt cross-culturally the De Morton Mobility Index from English to Brazilian Portuguese. Furthermore, to test the content validity, reliability, construct validity, interpretability and responsiveness for older hospitalized patients. Methods After we carried out the translation and the cross-cultural adaptation of the De Morton Mobility Index and its administration instructions according to international guidelines, the content validity of De Morton Mobility Index was tested by experienced physiotherapists. In the sequence, the reliability, construct validity, interpretability and responsiveness were tested in a test-retest design with 93 older patients hospitalized in ward for clinical reasons. The reliability was tested by Cronbach's alpha coefficient (internal consistency), standard error measurement (agreement), and interclass correlation coefficients (intra and inter-examiner reliability). The construct validity was tested by Pearson's correlation between the De Morton Mobility Index score and the number of steps. Interpretability was analyzed by determining the minimum detectable change and the floor and ceiling effects (frequency of maximum and minimum scoring). Responsiveness was analyzed by effect size. Results The Brazilian version of the De Morton Mobility Index was made and adapted. The internal consistency (α = 0.89), reliability intra-(ICC = 0.94) and inter-examiners (ICC = 0.82), agreement were all adequate. The De Morton Mobility Index is validity when correlated with number of steps (r = 0.46). Floor or ceiling effects (<15%) were not observed and the responsiveness was high (ES = 3.65). Conclusion The De Morton Mobility Index has shown adequate reliability, validity, interpretability and responsiveness for the evaluation of the mobility of older hospitalized patients.