Rasch analysis of 24-, 18- and 11-item versions of the Roland-Morris Disability Questionnaire

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.

Core muscle functional strength training for reducing the risk of low back pain in military recruits: An open-label randomized controlled trial

BACKGROUND

Core muscle functional strength training (CMFST) has been reported to reduce injuries to the lower extremity. However, no study has confirmed whether CMFST can reduce the risk of low back pain (LBP).

OBJECTIVE

This study identified the effects of CMFST on the incidence of LBP in military recruits.

DESIGN, SETTING, PARTICIPANTS AND INTERVENTION

We performed a prospective, open-label, randomized, controlled study in a population of young healthy male naval recruits from a Chinese basic combat training program. Participants were randomly assigned to either the core group or the control group. In additional to normal basic combat training, recruits in the core group underwent a CMFST program for 12 weeks, while recruits in the control group received no extra training.

MAIN OUTCOME MEASURES

At the beginning of the study and at the 12th week, the number of participants with LBP was counted, and lumbar muscle endurance was measured. In addition, when participants complained of LBP, they were assessed using the visual analog scale (VAS) and Roland Morris Disability Questionnaire (RMDQ).

RESULTS

A total of 588 participants were included in the final analysis (295 in the core group and 293 in the control group). The incidence of LBP in the control group was about twice that of the core group over the 12-week study (20.8% vs 10.8%, odds ratio: 2.161-2.159, P < 0.001). The core group had better lumbar muscle endurance at 12 weeks than the control group ([200.80 ± 92.98] s vs [147.00 ± 84.51] s, P < 0.01). There was no significant difference in VAS score between groups, but the core group had a significantly lower RMDQ score at week 12 than the control group (3.33 ± 0.58 vs 5.47 ± 4.41, P < 0.05).

CONCLUSION

This study demonstrated that the CMFST effectively reduced the incidence of LBP, improved lumbar muscle endurance, and relieved the dysfunction of LBP during basic military training.

Measuring the impact of chronic low back pain on everyday functioning: content validity of the Roland Morris disability questionnaire

BACKGROUND

Robust outcome measures are needed to assess and monitor the impact of chronic low back pain (CLBP) on physical functioning. The Roland Morris Disability Questionnaire (RMDQ) is a well-established measure designed to capture the impacts of back pain on everyday functioning, with a particular emphasis on physical functioning. It has documented evaluation of psychometric properties. However, there is no documented qualitative evidence to confirm the content validity of the tool, nor have changes made for electronic administration been debriefed in participants with CLBP.

METHODS

In-depth, semi-structured, concept elicitation and cognitive debriefing interviews were conducted with 23 US participants with confirmed CLBP. Interviews allowed participants to describe the impact of CLBP on their day-to-day functioning and discuss comprehension and suitability of the RMDQ. Interviews were transcribed verbatim and analyzed using thematic analysis.

RESULTS

Concept elicitation and cognitive debriefing revealed the substantial burden associated with CLBP, highlighting 15 key areas of functional impact. These were grouped into overarching themes of mobility (walking, stairs, sitting/standing, bending/kneeling, lifting, lying down), activities (chores/housework, dressing, washing, driving, work) and other (relationships/socializing, mood, sleep, appetite), which are consistent with those evaluated within the RMDQ. All participants found the RMDQ to be relevant with most reporting that the instructions, recall period, and response options were suitable. A few suggested minor changes, however, none were consistent or necessary to support content validity. Updates to the measure for electronic administration and to clarify the response options were well received.

CONCLUSION

The qualitative data from individuals with CLBP confirmed that the RMDQ has content validity and, alongside documented psychometric evidence, supports the use of the RMDQ as a reliable and valid tool to assess the impact of CLBP on physical functioning.

A systematic review highlights the need to investigate the content validity of patient-reported outcome measures for physical functioning in patients with low back pain

OBJECTIVES

To summarize the evidence on content and structural validity of 17 patient-reported outcome measures (PROMs) to measure physical functioning in patients with low back pain (LBP).

STUDY DESIGN AND SETTING

MEDLINE, EMBASE, CINAHL, PsycINFO, SportDiscus, and Google Scholar were searched (February 2017). Records on development and studies assessing content validity or unidimensionality in patients with LBP were included. Two reviewers defined eligible studies and assessed their methodological quality with updated Consensus-based Standards for the Selection of Health Measurement Instruments standards. Evidence was synthesized for three separate aspects of content validity: relevance, comprehensiveness, and comprehensibility, and for unidimensionality, a modified GRADE approach was applied to evidence synthesis.

RESULTS

High-quality evidence showed that 24-item Roland Morris Disability Questionnaire (RMDQ-24) is a comprehensible but not comprehensive PROM. Low to very low quality evidence underpinned the content validity of the other PROMs. Unidimensionality was: sufficient for Brief Pain Inventory pain interference subscale (moderate quality evidence); inconsistent for RMDQ-23, Oswestry Disability Index 2.1a (ODI 2.1a), and Quebec Back Pain Disability Scale (moderate quality); insufficient for RMDQ-24, ODI 1.0, and RMDQ-18 (high quality) and Short Form 36 physical functioning subscale (SF36-PF, moderate quality).

CONCLUSION

The content validity of PROMs to measure physical functioning in patients with LBP is understudied. Structural validity of several widely used PROMs is problematic.

Development of a short scale for assessing economic environmental aspects in patients with spinal diseases using Rasch analysis

Background

Economic environmental factors represent important barriers to participation and have deleterious effects on quality of life (QOL) in persons with spinal diseases (SpD). While economic factors are anchored in the International Classification of Functioning, Disability and Health, their influence on QOL and participation from patients’ perspectives is an infrequent focus of research. The aim of the present research is to calibrate a culturally adapted Rasch-based questionnaire assessing economic QOL in patients with SpD.

Methods

The 11-items of the German economic-QOL-scale were answered by 325 patients with SpD on a four-point Likert-scale. Fit to the Rasch measurement model was investigated by testing for stochastic ordering of the items, unidimensionality, local independence, and differential item functioning (DIF).

Results

After adjusting for local dependency, fit to the Rasch model was achieved with a non-significant item-trait interaction (chi-square_df = 20 = 34.8, p = 0.021). The person separation reliability equaled 0.88, the scale was free from age- or gender-related DIF, and unidimensionality could be verified.

Conclusions

The Rasch-based German version of the economic-QOL-scale represents a suitable instrument to investigate the influences of economic factors on patients’ QOL at a group and individual level. It can be easily applied in research and practice and may be administered quickly in combination with other instruments. The short test duration implies a low test burden for patients and a minimum of time expenditure by clinicians when evaluating the results.

Item response theory analysis to evaluate reliability and minimal clinically important change of the Roland-Morris Disability Questionnaire in patients with severe disability due to back pain from vertebral compression fractures

BACKGROUND CONTEXT

The majority of validation done on the Roland-Morris Disability Questionnaire (RMDQ) has been in patients with mild or moderate disability. There is paucity of research focusing on the psychometric quality of the RMDQ in patients with severe disability.

PURPOSE

To evaluate the psychometric quality of the RMDQ in patients with severe disability.

STUDY DESIGN/SETTING

Observational clinical study.

SAMPLE

The sample consisted of 214 patients with painful vertebral compression fractures who underwent vertebroplasty or kyphoplasty.

OUTCOME MEASURES

The 23-item version of the RMDQ was completed at two time points: baseline and 30-day postintervention follow-up.

METHODS

With the two-parameter logistic unidimensional item response theory (IRT) analyses, we derived the range of scores that produced reliable measurement and investigated the minimal clinically important difference (MCID).

RESULTS

Scores for 214 (100%) patients at baseline and 108 (50%) patients at follow-up did not meet the reliability criterion of 0.90 or higher, with the majority of patients having disability due to back pain that was too severe to be reliably measured by the RMDQ. Depending on methodology, MCID estimates ranged from 2 to 8 points and the proportion of patients classified as having experienced meaningful improvement ranged from 26% to 68%. A greater change in score was needed at the extreme ends of the score scale to be classified as having achieved MCID using IRT methods.

CONCLUSIONS

Replacing items measuring moderate disability with items measuring severe disability could yield a version of the RMDQ that better targets patients with severe disability due to back pain. Improved precision in measuring disability would be valuable to clinicians who treat patients with greater functional impairments. Caution is needed when choosing criteria for interpreting meaningful change using the RMDQ.

Roland-Morris Disability Questionnaire and Oswestry Disability Index: Which Has Better Measurement Properties for Measuring Physical Functioning in Nonspecific Low Back Pain? Systematic Review and Meta-Analysis

BACKGROUND

Physical functioning is a core outcome domain to be measured in nonspecific low back pain (NSLBP). A panel of experts recommended the Roland-Morris Disability Questionnaire (RMDQ) and Oswestry Disability Index (ODI) to measure this domain. The original 24-item RMDQ and ODI 2.1a are recommended by their developers.

PURPOSE

The purpose of this study was to evaluate whether the 24-item RMDQ or the ODI 2.1a has better measurement properties than the other to measure physical functioning in adult patients with NSLBP.

DATA SOURCES

Bibliographic databases (MEDLINE, Embase, CINAHL, SportDiscus, PsycINFO, and Google Scholar), references of existing reviews, and citation tracking were the data sources.

STUDY SELECTION

Two reviewers selected studies performing a head-to-head comparison of measurement properties (reliability, validity, and responsiveness) of the 2 questionnaires. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist was used to assess the methodological quality of these studies.

DATA EXTRACTION

The studies' characteristics and results were extracted by 2 reviewers. A meta-analysis was conducted when there was sufficient clinical and methodological homogeneity among studies.

DATA SYNTHESIS

Nine articles were included, for a total of 11 studies assessing 5 measurement properties. All studies were classified as having poor or fair methodological quality. The ODI displayed better test-retest reliability and smaller measurement error, whereas the RMDQ presented better construct validity as a measure of physical functioning. There was conflicting evidence for both instruments regarding responsiveness and inconclusive evidence for internal consistency.

LIMITATIONS

The results of this review are not generalizable to all available versions of these questionnaires or to patients with specific causes for their LBP.

CONCLUSIONS

Based on existing head-to-head comparison studies, there are no strong reasons to prefer 1 of these 2 instruments to measure physical functioning in patients with NSLBP, but studies of higher quality are needed to confirm this conclusion. Foremost, content, structural, and cross-cultural validity of these questionnaires in patients with NSLBP should be assessed and compared.

Reconsidering the Roland-Morris Disability Questionnaire: time for a multidimensional framework?

STUDY DESIGN

Cross-sectional design.

OBJECTIVE

To explore (1) the factor structure of the Roland-Morris Disability Questionnaire (RMDQ), (2) whether there is a dominant factor, and (3) whether the potential factors are unique predictors of other aspects related to back pain.

SUMMARY OF BACKGROUND DATA

The RMDQ is one of the most recommended back-specific questionnaires assessing disability. The RMDQ is scored as a unidimensional scale summarizing answers to all 24 questions (Yes/No) regarding daily life functioning. However, there are indications that the scale is multidimensional.

METHODS

Patients (n = 457; age, 18-60 yr) with 8 to 12 weeks of back pain filled in questionnaires assessing subjective health complaints, emotional distress, instrumental and emotion-focused coping, and fear voidance behavior at baseline. A total of 371 patients (81.7%) filled in the RMDQ. Exploratory factor analysis was used to examine the factor structure of RMDQ items. Multiple regression analyses were used to assess whether the derived factors predicted relevant problems in back pain differently.

RESULTS

Exploratory factor analysis showed indices of model fit for a 3-factor solution after removing 2 items because of low prevalence (19 and 24). Two items were removed because of cross-loadings and low loadings (2 and 22). No support for a dominant factor was found as the 3 factors were only moderately correlated (r = 0.34-0.40), and the ratio between the first and second eigenvalue was 2.6, not supporting essential unidimensionality. "Symptoms" were the factor that most strongly predicted subjective health complaints, whereas "avoidance of activity and participation" predicted fear avoidance behavior, instrumental and emotional coping. "Limitation in daily activities" did not predict any of these variables.

CONCLUSION

The main findings of our study are that the RMDQ consists of 3 independent factors, and not 1 dominant factor as suggested previously. We think the time is now ripe to start treating and scoring the RMDQ as a multidimensional scale.

LEVEL OF EVIDENCE

N/A.

Rasch analysis of the Italian version of fear avoidance beliefs questionnaire (FABQ-I)

PURPOSE

To perform a Rasch analysis (RA) of the Fear Avoidance Beliefs questionnaire (FABQ-I) in a sample of chronic non-specific low back pain (CLBP) patients. The RA is expected to provide information about the internal construct validity and all the single items consistency of the FABQ-I and then contributing to the knowledge about the questionnaire's clinimetric properties.

METHODS

One hundred and fifty subjects with CLBP were enrolled into the study. The FABQ-I have been studied by means of RA. The sample size needed to obtain stable person, item and rating-scale calibrations for use with the Rasch model was based on the level of error expected in the measure.

RESULTS

RA did not support the total scale as an unidimensional measure of Fear Avodiance Beliefs. Also the analysis of the Physical Activity (PA) and Word (WO) subscales as well as the attempts of manipulation failed in achieving an acceptable fit to the Rasch model.

CONCLUSION

FABQ-I may be considered to reflect a multiple psychological constructs describing scale. The raw score of the FABQ-I and changes in scores must be interpreted with caution because as a general measure of fear avoid beliefs was not supported.

Rasch analysis supports the use of the Pain Self-Efficacy Questionnaire

BACKGROUND

The Pain Self-Efficacy Questionnaire (PSEQ) is used by physical therapists in clinical practice and in research. However, current understanding of the PSEQ's measurement properties is incomplete, and investigators cannot be confident that it provides unbiased information on patient self-efficacy.

OBJECTIVE

The aims of this study were: (1) to investigate the scale properties of the PSEQ using Rasch analysis and (2) to determine whether age, sex, pain intensity, pain duration, and pain-related disability bias function of the PSEQ.

DESIGN

This was a retrospective study; data were obtained from 3 existing studies.

METHODS

Data were combined from more than 600 patients with low back pain of varying duration. Rasch analysis was used to evaluate targeting, category ordering, unidimensionality, person fit, internal consistency, and item bias.

RESULTS

There was evidence of adequate category ordering, unidimensionality, and internal consistency of the PSEQ. Importantly, there was no evidence of item bias.

LIMITATIONS

The PSEQ did not adequately target the sample; instead, it targeted people with lower self-efficacy than this population. Item 7 was hardest for participants to endorse, showing excessive positive misfit to the Rasch model. Response strings of misfitting persons revealed older participants and those reporting high levels of disability.

CONCLUSIONS

The individual items of the PSEQ can be validly summed to provide a score of self-efficacy that is robust to age, sex, pain intensity, pain duration, and disability. Although item 7 is the most problematic, it may provide important clinical information and requires further investigation before its exclusion. Although the PSEQ is commonly used with people with low back pain, of whom the sample in this study was representative, the results suggest it targets patients with lower self-efficacy than that observed in the current sample.

Derivation of an abbreviated instrument for use in emergency department low back pain research: the five-item Roland Morris Questionnaire

OBJECTIVES

Low back pain (LBP) is a common reason for emergency department (ED) visits in the United States. Pain and functional outcomes after ED visits for LBP tend to be poor. ED-based clinical LBP research is hampered by complexity of available outcome instruments, which can be time-consuming to administer. The purpose of this investigation was to determine if a shorter version of the well-validated and commonly used Roland Morris Disability Questionnaire (RMDQ) would retain the original 24-item instrument's ability to assess functional outcomes accurately in ED patients with LBP.

METHODS

The authors used deidentified data obtained from a prospective LBP cohort study, which enrolled 674 patients during index ED visits for LBP, and followed them by telephone 1 week and 3 months later. Five items were selected from the original 24 items of the RMDQ using regression techniques. Internal consistency of the abbreviated scale was measured using Cronbach's alpha. The strength of association between the five-item scale (RM5) and the parent scale was determined at baseline, 1 week, and 3 months. The association between change in the parent scale and change in the RM5 and the change in RM5 that was most closely associated with a minimum clinically significant difference on the RMDQ were also determined.

RESULTS

The Cronbach's alpha for the RM5 was 0.88 (95% confidence interval [CI] = 0.87 to 0.89) at baseline, 0.96 (95% CI = 0.96 to 0.96) at 7 days, and 0.97 (95% CI = 0.97 to 0.97) at 3 months. The Pearson correlation coefficient for the RM5 versus the parent scale was 0.93 (R(2)  = 0.86) at baseline, 0.98 (R(2)  = 0.96) at 1 week, and 0.98 (R(2)  = 0.96) at 3 months. The correlations between change from baseline in the abbreviated scale and the parent scale were 0.95 (R(2)  = 0.90) and 0.96 (R(2)  = 0.92) at 7 days and 3 months, respectively. A one-point change in the RM5 has a sensitivity of 96% (95% CI = 93% to 98%) and a specificity of 92% (95% CI = 89% to 94%) for the minimum clinically significant change on the RMDQ.

CONCLUSIONS

An abbreviated five-item version of the RMDQ was developed. Pending independent validation, this shortened instrument should streamline ED-based low back pain research.

Detecting insomnia in patients with low back pain: accuracy of four self-report sleep measures

Background

Although insomnia is common in patients with low back pain (LBP), it is unknown whether commonly used self-report sleep measures are sufficiently accurate to screen for insomnia in the LBP population. This study investigated the discriminatory properties of the Pittsburgh Sleep Quality Index (Pittsburgh questionnaire), Insomnia Severity Index (Insomnia index), Epworth Sleepiness Scale (Epworth scale) and the sleep item of the Roland and Morris Disability Questionnaire (Roland item) to detect insomnia in patients with LBP by comparing their accuracy to detect insomnia to a sleep diary. The study also aimed to determine the clinical optimal cut-off scores of the questionnaires to detect insomnia in the LBP population.

Methods

Seventy nine patients with LBP completed the four self-reported questionnaires and a sleep diary for 7 consecutive nights. The accuracy of the questionnaires was evaluated using Receiver Operator Characteristic (ROC) curves with the Area Under the Curve (AUC) used to examine each test’s accuracy to discriminate participants with insomnia from those without insomnia.

Results

The Pittsburgh questionnaire and Insomnia index had moderate accuracy to detect insomnia (AUC = 0.79, 95% CI = 0.68 to 0.87 and AUC = 0.78, 95% CI = 0.67 to 0.86 respectively), whereas the Epworth scale and the Roland item were not found to be accurate discriminators (AUC = 0.53, 95% CI = 0. 41 to 0.64 and AUC = 0.64, 95% CI = 0.53 to 0.75 respectively). The cut-off score of > 6 for the Pittsburgh questionnaire and the cut-off point of > 14 for the Insomnia index provided optimal sensitivity and specificity for the detection of insomnia.

Conclusions

The Pittsburgh questionnaire and Insomnia index had similar ability to screen for insomnia in patients with low back pain.

Does a patient's physical activity predict recovery from an episode of acute low back pain? A prospective cohort study

Background

Advice to remain active and normalisation of activity are commonly prescribed in the management of low back pain (LBP). However, no research has assessed whether objective measurements of physical activity predict outcome and recovery in acute low back pain.

Method

The aims of this study were to assess the predictive relationship between activity and disability at 3 months in a sub-acute LBP population. This prospective cohort study recruited 101 consenting patients with sub-acute LBP (< 6 weeks) who completed the Roland Morris Disability Questionnaire (RMDQ), the Visual Analogue Scale, and resumption of full ‘normal’ activity question (Y/N), at baseline and 3 months. Physical activity was measured for 7 days at both baseline and at 3 months with an RT3 accelerometer and a recall questionnaire.

Results

Observed and self-reported measures of physical activity at baseline and change in activity from baseline to 3 months were not independent predictors of RMDQ (p > 0.05) or RMDQ change (p > 0.05) over 3 months. A self-report of a return to full ‘normal’ activities was significantly associated with greater RMDQ change score at 3 months (p < 0.001). Paired t-tests found no significant change in activity levels measured with the RT3 (p = 0.57) or the recall questionnaire (p = 0.38) from baseline to 3 months.

Conclusions

These results question the predictive role of physical activity in LBP recovery, and the assumption that activity levels change as LBP symptoms resolve. The importance of a patient’s perception of activity limitation in recovery from acute LBP was also highlighted.

Trial registration

Clinical Trial Registration Number, ACTRN12609000282280

The development of the MACE work-family enrichment instrument

Orientation: An instrument based on a theoretical model is necessary to measure the positive side of the work-family interface.Research purpose: To develop items for measurement of work-family enrichment based on the elements contained within a theoretical model and to evaluate the latent trait functioning of these items.Motivation for the study: Major limitations exist regarding the conceptualisation and scale development of the positive side of the work-family interface.Research design, approach, and method: A quantitative research approach using scale development procedures was employed to develop the 95-item instrument. A cross-sectional survey design was used to collect data randomly from selected employees; data were processed using Rasch analysis.Main findings: The five-category scale works well for the most part, although a four-category scale could be considered. Thirty-five items either over-fitted or under-fitted the work-family enrichment model. Person ability was measured in the low to middle ranges of work-family enrichment. Participants’ experience of work-family enrichment could be represented accurately. Sub-scale items displayed misfit, bias or both.Practical/managerial implications: The developed instrument can be investigated further to identify work-family enrichment factors that can measure workers’ experience of enrichment in their work and family domains.Contribution/value-add: This study furthers theory building and empirical research in industrial psychology, by developing a new theory-based measuring instrument for the positive side of the work-family interface in the South African context. This study expanded on the model proposed by Greenhaus and Powell, by including all five categories of resources gains. Furthermore, the total of the resources was diversified, since some of the content of these resources encompasses multiple meanings.

Translation and validation of the Dutch version of the Effective Consumer Scale (EC-17)

PURPOSE

The Effective Consumer Scale (EC-17) measures the skills of musculoskeletal patients in managing their own healthcare. The objectives of this study were to translate the EC-17 into Dutch and to further evaluate its psychometric properties.

METHODS

The EC-17 was translated and cognitively pretested following cross-cultural adaptation guidelines. Two hundred and thirty-eight outpatients (52 % response rate) with osteoarthritis or fibromyalgia completed the EC-17 along with other validated measures. Three weeks later, 101 patients completed the EC-17 again.

RESULTS

Confirmatory factor analysis supported the unidimensional structure of the scale. The items adequately fit the Rasch model and only one item demonstrated differential item functioning. Person reliability was high (0.92), but item difficulty levels tended to cluster around the middle of the scale, and measurement precision was highest for moderate and lower levels of skills. The scale demonstrated adequate test-retest reliability (ICC = 0.71), and correlations with other measures were largely as expected.

CONCLUSION

The results supported the validity and reliability of the Dutch version of the EC-17, but suggest that the scale is best targeted at patients with relatively low levels of skills. Future studies should further examine its sensitivity to change in a clinical trial specifically aimed at improving effective consumer skills.

Reliability and validity of simplified Chinese version of Roland-Morris questionnaire in evaluating rural and urban patients with low back pain

Objective

The causes of low back pain in China and Western countries are extremely different. We attempted to analyze the risk factors of low back pain in urban and rural patients under the dual economy with the simplified Chinese version of Roland-Morris disability questionnaire (SC-RMDQ) to demonstrate that SC-RMDQ could evaluate patients with low back pain arising from different causes.

Methods

Roland-Morris disability questionnaire was translated into SCRMDQ according to international guidelines for questionnaire adaptation. In this study, causes of low back pain of 187 outpatients and inpatients (99 urban patients and 88 rural patients) were analyzed. All patients underwent simplified Chinese version of Roland-Morris disability questionnaire (SC-RMDQ), simplified Chinese Oswestry disability index (SCODI) and visual analogue scale (VAS). Reliability was tested using reproducibility (intraclass coefficient of correlation – ICC) and internal consistency (Cronbach's alpha). Validity was tested using Pearson correlation analysis.

Results

The leading causes for low back pain were sedentariness (38.4%) and vibration (18.1%) in urban patients and waist bending (48.9%) and spraining (25%) in rural patients. Although causes of low back pain in the two groups of population were completely different, SCRMDQ had high internal consistency (Cronbach's α value of 0.874 in urban patients and 0.883 in rural patients) and good reproducibility (ICC value of .952 in urban patients and 0.949 in rural patients, P<0.01). SCRMDQ also showed significant correlation with Simplified Chinese version of Oswestry disability index (SCODI) and visual analogue scale (VAS) in rural areas (SCRMDQ-SCODI r = 0.841; SCRMDQ -VAS: r = 0.685, P<0.01) and in urban areas (SCRMDQ-SCODI: r = 0.818, P<0.01; SCRMDQ –VAS: r = 0.666, P<0.01).

Conclusions

Although causes of low back pain are completely different in rural and urban patients, SCRMDQ has a good reliability and validity, which is a reliable clinical method to evaluate disability of rural and urban patients.

Internal construct validity of the Swiss Spinal Stenosis questionnaire: Rasch analysis of a disease-specific outcome measure for lumbar spinal stenosis

STUDY DESIGN

Rasch analysis of an outcome tool using data from questionnaires completed by patients with lumbar spinal stenosis.

OBJECTIVE

To evaluate the psychometric properties of the Swiss Spinal Stenosis questionnaire using the Rasch measurement model.

SUMMARY OF BACKGROUND DATA

Lumbar spinal stenosis (LSS) is a common cause of low back pain and leg symptoms in older patients. The SSS questionnaire was devised as a condition-specific outcome measure for patients with LSS. It comprises two subscales; one to measure symptom severity and another to measure physical functioning. The SSS is commonly used in trials for patients with LSS but has not, to our knowledge, been subjected to rigorous modern psychometric analysis methods.

METHODS

Data from a total of 190 SSS assessments in 98 people with LSS were fitted to the Rasch measurement model. This method was used to examine the validity of the item scoring functions, the presence of item bias or differential item functioning and the fit of data to model expectations. In addition, the analysis was used to assess whether or not the item set in each scale formed a unidimensional scale to provide a valid summed score.

RESULTS

The symptom severity scale and the physical function scale of the SSS were found to be reliable and well targeted to the study population. However, the symptom severity scale was found to be multidimensional; three items focused on pain and four items on neuroischemic symptoms. The physical function scale performed well as a unidimensional scale, but needed to be modified by excluding one item in order for it to fit the Rasch model.

CONCLUSION

Development of a more robust measurement tool for this patient group may be warranted. A new tool may need to include three scales to measure the separate domains of pain severity, neuroischemic symptom severity, and physical function.

Rasch analysis of the Patient and Observer Scar Assessment Scale (POSAS) in burn scars

PURPOSE

The Patient and Observer Scar Assessment Scale (POSAS) is a questionnaire that was developed to assess scar quality. It consists of two separate six-item scales (Observer Scale and Patient Scale), both of which are scored on a 10-point rating scale. After many years of experience with this scale in burn scar assessment, it is appropriate to examine its psychometric properties using Rasch analysis.

METHODS

Cross-sectional data collection from seven clinical trials resulted in a data set of 1,629 observer scores and 1,427 patient scores of burn scars. We examined the person-item map, item fit statistics, reliability, response category ordering, and dimensionality of the POSAS.

RESULTS

The POSAS showed an adequate fit to the Rasch model, except for the item surface area. Person reliability of the Observer Scale and Patient Scale was 0.82 and 0.77, respectively. Dimensionality analysis revealed that the unexplained variance by the first contrast of both scales was 1.7 units. Spearman correlation between the Observer Scale Rasch measure and the overall opinion of the clinician was 0.75.

CONCLUSION

The Rasch model demonstrated that the POSAS is a reliable and valid scale that measures the single-construct scar quality.

Responsiveness of the 24-, 18- and 11-item versions of the Roland Morris Disability Questionnaire

Several versions of the 24-item Roland Morris Disability Questionnaire (RMDQ) have been proposed; however, their responsiveness has not been extensively explored. The objective of this study was to compare the responsiveness of four versions of the RMDQ. Perceived disability was measured using the 24-item, two 18-item and an 11-item RMDQ on 1,069 low back pain patients from six randomised controlled trials. Responsiveness was calculated using effect size, Guyatt's responsiveness index (GRI) and receiver operating characteristics (ROC) curves. Effect size analyses showed that both 18-item versions of the RMDQ were superior to the 24- and 11-item versions of the RMDQ. GRI showed that the 24- and 18-item versions of the RMDQ were similar but more responsive than the 11-item. ROC curves revealed that the 11-item was less responsive than the other three versions, which had similar responsiveness. The results of this study demonstrate that the 24-item and both 18-item versions of the RMDQ have similar responsiveness with all having superior responsiveness to the 11-item.

Psychometric properties of the Fatigue Severity Scale in polio survivors

The objective of this study was to evaluate by means of classical test theory and Rasch analysis the scaling characteristics and psychometric properties of the Fatigue Severity Scale (FSS) in polio survivors. A questionnaire,consisting of five general questions (sex, age, age at time of acute polio, sequelae of polio, and new symptoms), the FSS, and three questions from the Visual Analog Scale questions on fatigue was sent to all 196 polio survivors at the Institute for Rehabilitation in Ljubljana. Responses were assessed in terms of Cronbach's a, item-to-total correlation, factor analysis, and Rasch analysis. Of the128 (65.3%) valid questionnaires returned, those presenting no missing values were used for subsequent analyses (n = 117). The FSS showed good internal consistency: Cronbach's a was greater than 0.95,item-to-total correlation ranged from 0.68 to 0.88. A reduction from seven to three rating categories was necessary to comply with criteria for correct category function. Item difficulty estimates spanned from – 0.91to + 1.09 logits. No item bias was found for sex and age.The internal consistency of FSS was high and its item separation reliability good, indicating a satisfactory replicability of item placement in other samples. In conclusion, Rasch analysis enabled us to confirm the validity of FSS (in its 8-item version, without item 1) as a measure of the severity and impact of physical symptoms of fatigue in polio survivors, so providing a useful starting point for further studies aimed at examining additional psychometric aspects and confirming the appropriateness of the simplification of its rating categories.

A modified Roland-Morris disability scale for the assessment of sciatica

BACKGROUND

The Roland-Morris disability scale (RMS) for disability secondary to low back pain is a validated and popular instrument in clinical practice and research. We have made a simple modification to the questionnaire to increase sensitivity to sciatica (RMS-L) and validated this in patients with lumbar disc prolapse and radiculopathy.

METHODS

The original RMS and modified RMS-L were prospectively administered to 203 patients presenting with lumbar radiculopathy and intervertebral disc prolapse demonstrated on MRI. Scores at pre-operative assessment and follow-up at 3 months and 12-24 months were compared against visual analogue scores (VAS) and Short Form 36 generic health domains.

FINDINGS

Correlation between RMS-L and VAS leg pain was significantly greater than between original RMS and VAS leg pain pre-operatively (r = 0.57 vs. 0.17, p < 0.001) and at 3 months follow-up (r = 0.78 vs. 0.49, p < 0.001). Conversely, correlation between RMS and VAS back pain was significantly higher (r = 0.58 vs. 0.15, p < 0.001). Compared with RMS, at pre-operative assessment, RMS-L showed greater correlation with SF-36 physical function (PF; r = -0.57 vs. -0.32, p < 0.001) and bodily pain (r = -0.58 vs. -0.35, p < 0.001). Similarly, the change in PF to 3 months follow-up showed significantly higher correlation with change in RMS-L compared with the change in RMS (r = -0.60 vs. -0.37, p < 0.001). Effect sizes were good for RMS-L (1.19-1.24) but only moderate for RMS (0.69-0.79).

CONCLUSIONS

The original and modified RMS can discriminate disability due to low back pain and sciatica, respectively. Separate assessment of these symptoms and their contribution to functional impairment is useful in assessing suitability for surgery and predicting outcome.

Using psychometric techniques to improve the Balance Evaluation Systems Test: the mini-BESTest

OBJECTIVE

To improve, with the aid of psychometric analysis, the Balance Evaluation Systems Test (BESTest), a tool designed to analyse several postural control systems that may contribute to poor functional balance in adults.

METHODS

Performance of the BESTest was examined in a convenience sample of 115 consecutive adult patients with diverse neurological diagnoses and disease severity, referred to rehabilitation for balance disorders. Factor (both explorative and confirmatory) and Rasch analysis were used to process the data in order to produce a new, reduced and coherent balance measurement tool.

RESULTS

Factor analysis selected 24 out of the 36 original BESTest items likely to represent the unidimensional construct of "dynamic balance". Rasch analysis was then used to: (i) improve the rating categories, and (ii) delete 10 items (misfitting or showing local dependency). The model consisting of the remaining 14 tasks was verified with confirmatory factor analysis to meet the stringent requirements of modern measurement.

CONCLUSION

The new 14-item scale (dubbed mini-BESTest) focuses on dynamic balance, can be conducted in 10-15 min, and contains items belonging evenly to 4 of the 6 sections from the original BESTest. Further studies are needed to confirm the usefulness of the mini-BESTest in clinical settings.