The internal structure of Brazilian versions of disability questionnaires in patients with chronic low back pain: A cross-sectional study

The best structure of the Tampa Scale for Kinesiophobia for patients with chronic low back pain has two domains and nine items

PURPOSE

To identify the best internal structure of the Tampa Scale for Kinesiophobia in chronic low back pain patients.

DESIGN

Questionnaire validation study was designed for this study.

SETTING

This study was conducted in physical therapy facility.

SUBJECTS

Respondents reporting chronic low back pain (≥3 points on the 11-point Numerical Pain Rating Scale).

MAIN MEASURES

We included participants of both sexes, with a self-report of low back pain ≥3 months and with pain intensity ≥3 on the 11-point Numerical Pain Rating Scale; participants also answered the Roland-Morris Disability Questionnaire and the Pain-Related Catastrophizing Thoughts Scale for low back pain disability and catastrophizing, respectively. The dimensionality and number of items of the Tampa Scale for Kinesiophobia were evaluated using the confirmatory factor analysis. Criterion validity was assessed using Spearman's correlation coefficient using the original version of the 17-item Tampa Scale for Kinesiophobia as the gold standard.

RESULTS

A total of 122 participants were included, with mean values of low back pain duration ≥48 months, pain intensity >5 and disability >8. Tampa Scale for Kinesiophobia structure with two domains and nine items was the most suitable, with adequate values in all fit indices (Chi-square/degree of freedom <3, Comparative Fit Index and Tucker-Lewis Index >0.90, and root mean square error of approximation <0.08) and lower Akaike information criterion and Bayesian information criterion values. We observed a high correlation between the 17-item Tampa Scale for Kinesiophobia and the activity avoidance domain (rho = 0.850, P < 0.001) and somatic focus domain (rho = 0.792, P < 0.001) of the nine-item Tampa Scale for Kinesiophobia.

CONCLUSION

Tampa Scale for Kinesiophobia structure with two domains (activity avoidance and somatic focus) and nine items is the most suitable for patients with chronic low back pain.

15-item Roland-Morris Disability Questionnaire (RMDQ-15): structural and criterion validity on patients with chronic low back pain

Background

The Roland-Morris Disability Questionnaire (RMDQ) is one of the most used instruments to measure self-reported disability in patients with low back pain, however, the uncertainty on which version to use may lead to inadequate disability measurement and consequently, improper management of patients with chronic low back pain.

Objective

To propose a short version of the RMDQ, compare it with the other short versions presented by the specialized literature, and identify the best internal structure of the RMDQ for the Brazilian population.

Methods

This is a cross-sectional study in which we used confirmatory factor analysis to identify the best structure of the RMDQ. We assessed 545 participants, most of which were women, aged ≥ 30 years old, single, with mean low back pain intensity ~ 5 points, and mean pain chronicity ~ 72 months. We used lavaan and semPlot packages, with implementation of a tetrachoric matrix and the robust diagonally weighted least squares extraction method. We also used fit indices chi-square/degree of freedom, comparative fit index, Tucker-Lewis index, root mean square error of approximation, and standardized root mean squared residual. For the comparison between models, we considered the structure with the lowest values of the Akaike information criterion and Bayesian information criterion. In addition, we assessed criterion validity via Spearman’s correlation coefficient to correlate the long and short versions. In this study, the 15-item structure was created through the use of modification indices to identify redundant items (9 items were excluded).

Results

RMDQ structure with one domain and 15 items and the structure with two domains and 16 items showed all fit indices with adequate values, but the one-dimensional version showed the lowest Akaike information criterion and Bayesian information criterion values. Regarding criterion validity, correlation between the RMDQ with 24 items and 15 items is adequate (rho = 0.954, p < 0.001).

Conclusion

The RMDQ-15 is a short version of the RMDQ instrument with the most adequate internal structure and satisfactorily correlated with the long version of the instrument.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05953-y.