Letting the CAT out of the bag: comparing computer adaptive tests and an 11-item short form of the Roland-Morris Disability Questionnaire

Contemporary Review: An Overview of the Utility of Patient-Reported Outcome Measurement Information System (PROMIS) in Foot and Ankle Surgery

Patient-Reported Outcome Measurement Information System (PROMIS) has favorable psychometric and administrative properties in orthopaedic clinical research. It facilitates clinically meaningful data collection while minimizing administration time and survey fatigue and improving compliance. PROMIS is a critical component of patient-centered care and shared decision making, as it provides enhanced communication and engagement between patients and providers. As a validated instrument, it may also aid in measuring value-based health care quality. The goal of the current work is to provide an overview of PROMIS metrics used in orthopaedic foot and ankle, including advantages and disadvantages compared to legacy scales and PROMIS's applicability in specific foot and ankle conditions based on psychometric properties. We provide a review of the literature regarding the utilization of PROMIS as an outcome measure for specific foot and ankle procedures and conditions.

Development of an item bank for measuring prosthetic mobility in people with lower limb amputation: The Prosthetic Limb Users Survey of Mobility (PLUS-M)

BACKGROUND

Achieving mobility with a prosthesis is a common post-amputation rehabilitation goal and primary outcome in prosthetic research studies. Patient-reported outcome measures (PROMs) available to measure prosthetic mobility have practical and psychometric limitations that inhibit their use in clinical care and research.

OBJECTIVE

To develop a brief, clinically meaningful, and psychometrically robust PROM to measure prosthetic mobility.

DESIGN

A cross-sectional study was conducted to administer previously developed candidate items to a national sample of lower limb prosthesis users. Items were calibrated to an item response theory model and two fixed-length short forms were created. Instruments were assessed for readability, effective range of measurement, agreement with the full item bank, ceiling and floor effects, convergent validity, and known groups validity.

SETTING

Participants were recruited using flyers posted in hospitals and prosthetics clinics across the United States, magazine advertisements, notices posted to consumer websites, and direct mailings.

PARTICIPANTS

Adult prosthesis users (N = 1091) with unilateral lower limb amputation due to traumatic or dysvascular causes.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Candidate items (N = 105) were administered along with the Patient Reported Outcome Measurement Information System Brief Profile, Prosthesis Evaluation Questionnaire - Mobility Subscale, and Activities-Specific Balance Confidence Scale, and questions created to characterize respondents.

RESULTS

A bank of 44 calibrated self-report items, termed the Prosthetic Limb Users Survey of Mobility (PLUS-M), was produced. Clinical and statistical criteria were used to select items for 7- and 12-item short forms. PLUS-M instruments had an 8th grade reading level, measured with precision across a wide range of respondents, exhibited little-to-no ceiling or floor effects, correlated expectedly with scores from existing PROMs, and differentiated between groups of respondents expected to have different levels of mobility.

CONCLUSION

The PLUS-M appears to be well suited to measuring prosthetic mobility in people with lower limb amputation. PLUS-M instruments are recommended for use in clinical and research settings.

Responsiveness of the UW Concerns About Pain Scale and UW Pain-Related Self-Efficacy Scale in Individuals With Chronic Low Back Pain

OBJECTIVES

The aim was to examine the responsiveness, presence of floor or ceiling effects, and minimal clinically important differences (MCIDs) for 2 new measures of pain-related catastrophizing and self-efficacy in individuals with chronic low back pain.

METHODS

A total of 183 individuals with chronic low back pain recruited from physical therapy clinics in Thailand completed the Thai versions of the 6-item University of Washington Concerns About Pain scale (T-UW-CAP6) and 6-item University of Washington Pain-Related Self-Efficacy scale (T-UW-PRSE6) at baseline and at 4 weeks follow-up. Perceived change in low back symptom was assessed at 4 weeks using a 7-point measure of Global Perceived Effect (GPE). Responsiveness of the T-UW-CAP6 and the T-UW-PRSE6 scale scores were evaluated by computing the effect sizes and standardized response means for change over time, and examining these as a function of the GPE ratings. Floor and ceiling effects were examined by evaluating the score distributions. Scale core MCIDs were estimated by computing a half a SD and SE of measurement statistics for each scale.

RESULTS

Responsiveness of the scales to pain treatment was supported by differences found in the mean change scores as a function of the treatment response categories. No significant floor or ceiling effects were found for either measure. Changes of 4.38 and 3.68 appeared to be the smallest change score perceived as clinical meaningful for the T-UW-CAP6 and T-UW-PRSE 6 scale scores, respectively.

DISCUSSION

The T-UW-CAP6 and T-UW-PRSE6 demonstrated good ability to detect perceived changes over time in patients with chronic low back pain. The MCIDs values provide a benchmark for assessing individual improvement in this clinical context.

Patient-Reported Outcome Measurement Information System (PROMIS) in Orthopaedic Trauma Research

This review describes the development, advantages and disadvantages, and applications of the Patient-Reported Outcome Measurement Information System (PROMIS) in orthopaedic trauma. PROMIS is a useful tool for quantifying outcomes in orthopedic trauma. It allows measurement of outcomes across multiple domains while minimizing administration time. PROMIS also reliably identifies clinical, social, and psychological risk factors for poor outcomes across a variety of orthopaedic injuries and disease states. However, PROMIS lacks specificity for certain anatomic regions and validation for mental health outcomes. It also is limited by ceiling effects in certain active patient populations. Orthopaedic traumatologists should be familiar with PROMIS, as its use is increasing and it is a valuable tool that can aid in clinical decision making.

The Concerns About Pain (CAP) Scale: A Patient-Reported Outcome Measure of Pain Catastrophizing

Pain catastrophizing has been recognized as an important and consistent psychosocial predictor of nearly every key pain-related outcome. The purpose of this study was to develop a new measure of pain catastrophizing using modern psychometric methodology. People with chronic pain (N = 795) responded to thirty items. Data were analyzed using item response theory, including assessment of differential item functioning and reliability. Sensitivity to change and validity were examined using data collected from patients undergoing spinal fusion surgery (n = 184) and participating in an ongoing longitudinal aging with a disability survey study (n = 1,388). The final 24-item bank had no items with significant local dependence, misfit, or differential item functioning. Results provided strong evidence of reliability and validity. Six- and 2-item short forms were developed for use when computer adaptive testing is not feasible or desirable. The item bank was named the University of Washington Concerns About Pain scale because the term "catastrophizing" was considered stigmatizing by people with chronic pain. Guidance for score interpretation was developed with extensive feedback from individuals with chronic pain. The Concerns About Pain item bank, short forms, and user manuals are free and publicly available to all users and can be accessed online at https://uwcorr.washington.edu/measures/. PERSPECTIVE: This article presents the development of the University of Washington Concerns About Pain scale, the first item response theory-based item bank of pain catastrophizing. The measure is intended for clinicians interested in improving outcomes of patients with chronic pain and for researchers who study impact of and treatment interventions aimed at reducing pain catastrophizing.

Measuring Pain Catastrophizing and Pain-Related Self-Efficacy: Expert Panels, Focus Groups, and Cognitive Interviews

PURPOSE

Pain-related self-efficacy and pain catastrophizing are important psychosocial determinants of pain and can be therapeutic targets for chronic pain management. Advances in psychometric science have made shorter or dynamically administered instruments possible. The aim of this study was to generate and test candidate items for two new patient-reported outcome measures of pain-related self-efficacy and pain catastrophizing.

METHODS

An expert panel of pain clinicians and researchers was convened to establish construct definitions of pain-related self-efficacy and pain catastrophizing and guide item development. Two patient advisors provided guidance throughout the project. Nineteen people with chronic pain participated in focus groups about their perspectives and experiences related to pain-related self-efficacy and pain catastrophizing. Twenty-two people with chronic pain participated in cognitive interviews to test proposed candidate items.

RESULTS

Saturation was reached after three focus groups with no new subdomains identified by participants in the third focus group. Following cognitive interviews, five of the 48 initial pain-related self-efficacy candidate items were dropped and seven required substantial revision resulting in 43 pain-related self-efficacy candidate items. After two rounds of cognitive interviews, ten items were eliminated and ten substantially revised, resulting in a set of 30 from the initial 43 pain catastrophizing candidate items.

CONCLUSION

This article summarizes results of the qualitative phase of the development of new measures of pain-related self-efficacy and pain catastrophizing. Candidate items will be field tested with a large sample of people with chronic pain and the data will be used to calibrate items to an item response theory model. Resulting item banks and short forms will be made publicly available to researchers and clinicians.

A comparison of computerized adaptive testing and fixed-length short forms for the Prosthetic Limb Users Survey of Mobility (PLUS-MTM)

BACKGROUND

New health status instruments can be administered by computerized adaptive test or short forms. The Prosthetic Limb Users Survey of Mobility (PLUS-MTM) is a self-report measure of mobility for prosthesis users with lower limb loss. This study used the PLUS-M to examine advantages and disadvantages of computerized adaptive test and short forms.

OBJECTIVES

To compare scores obtained from computerized adaptive test to scores obtained from fixed-length short forms (7-item and 12-item) in order to provide guidance to researchers and clinicians on how to select the best form of administration for different uses.

STUDY DESIGN

Cross-sectional, observational study.

METHODS

Individuals with lower limb loss completed the PLUS-M by computerized adaptive test and short forms. Administration time, correlations between the scores, and standard errors were compared.

RESULTS

Scores and standard errors from the computerized adaptive test, 7-item short form, and 12-item short form were highly correlated and all forms of administration were efficient. Computerized adaptive test required less time to administer than either paper or electronic short forms; however, time savings were minimal compared to the 7-item short form.

CONCLUSION

Results indicate that the PLUS-M computerized adaptive test is most efficient, and differences in scores between administration methods are minimal. The main advantage of the computerized adaptive test was more reliable scores at higher levels of mobility compared to short forms. Clinical relevance Health-related item banks, like the Prosthetic Limb Users Survey of Mobility (PLUS-MTM), can be administered by computerized adaptive testing (CAT) or as fixed-length short forms (SFs). Results of this study will help clinicians and researchers decide whether they should invest in a CAT administration system or whether SFs are more appropriate.

The use of computer adaptive tests in outcome assessments following upper limb trauma: a systematic review

Aims

Outcome measures quantifying aspects of health in a precise, efficient, and user-friendly manner are in demand. Computer adaptive tests (CATs) may overcome the limitations of established fixed scales and be more adept at measuring outcomes in trauma. The primary objective of this review was to gain a comprehensive understanding of the psychometric properties of CATs compared with fixed-length scales in the assessment of outcome in patients who have suffered trauma of the upper limb. Study designs, outcome measures and methodological quality are defined, along with trends in investigation.

Materials and Methods

A search of multiple electronic databases was undertaken on 1 January 2017 with terms related to "CATs", "orthopaedics", "trauma", and "anatomical regions". Studies involving adults suffering trauma to the upper limb, and undergoing any intervention, were eligible. Those involving the measurement of outcome with any CATs were included. Identification, screening, and eligibility were undertaken, followed by the extraction of data and quality assessment using the Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) criteria. The review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria and reg istered (PROSPERO: CRD42016053886).

Results

A total of 31 studies reported trauma conditions alone, or in combination with non-traumatic conditions using CATs. Most were cross-sectional with varying level of evidence, number of patients, type of study, range of conditions and methodological quality. CATs correlated well with fixed scales and had minimal or no floor-ceiling effects. They required significantly fewer questions and/or less time for completion. Patient-Reported Outcomes Measurement Information System (PROMIS) CATs were the most frequently used, and the use of CATs is increasing.

Conclusion

Early studies show valid and reliable outcome measurement with CATs performing as well as, if not better than, established fixed scales. Superior properties such as floor-ceiling effects and ease of use support their use in the assessment of outcome after trauma. As CATs are being increasingly used in patient outcomes research, further psychometric evaluation, especially involving longitudinal studies and groups of patients with specific injuries are required to inform clinical practice using these contemporary measures. Cite this article: Bone Joint J 2018;100-B:693-702.

Focused Evidence Review: Psychometric Properties of Patient-Reported Outcome Measures for Chronic Musculoskeletal Pain

BACKGROUND

Developing successful interventions for chronic musculoskeletal pain requires valid, responsive, and reliable outcome measures. The Minneapolis VA Evidence-based Synthesis Program completed a focused evidence review on key psychometric properties of 17 self-report measures of pain severity and pain-related functional impairment suitable for clinical research on chronic musculoskeletal pain.

METHODS

Pain experts of the VA Pain Measurement Outcomes Workgroup identified 17 pain measures to undergo systematic review. In addition to a MEDLINE search on these 17 measures (1/2000-1/2017), we hand-searched (without publication date limits) the reference lists of all included studies, prior systematic reviews, and-when available-Web sites dedicated to each measure (PROSPERO registration CRD42017056610). Our primary outcome was the measure's minimal important difference (MID). Secondary outcomes included responsiveness, validity, and test-retest reliability. Outcomes were synthesized through evidence mapping and qualitative comparison.

RESULTS

Of 1635 abstracts identified, 331 articles underwent full-text review, and 43 met inclusion criteria. Five measures (Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RMDQ), SF-36 Bodily Pain Scale (SF-36 BPS), Numeric Rating Scale (NRS), and Visual Analog Scale (VAS)) had data reported on MID, responsiveness, validity, and test-retest reliability. Seven measures had data reported on three of the four psychometric outcomes. Eight measures had reported MIDs, though estimation methods differed substantially and often were not clinically anchored.

CONCLUSIONS

In this focused evidence review, the most evidence on key psychometric properties in chronic musculoskeletal pain populations was found for the ODI, RMDQ, SF-36 BPS, NRS, and VAS. Key limitations in the field include substantial variation in methods of estimating psychometric properties, defining chronic musculoskeletal pain, and reporting patient demographics.

TRIAL REGISTRATION

Registered in the PROSPERO database: CRD42017056610.

Correlation of PROMIS Physical Function Upper Extremity Computer Adaptive Test with American Shoulder and Elbow Surgeons shoulder assessment form and Simple Shoulder Test in patients with shoulder arthritis

BACKGROUND

The purpose of this study was to evaluate the Patient-Reported Outcomes Measurement Informative System Physical Function Upper Extremity Computer Adaptive Test (PROMIS PFUE CAT) measurement tool against the already validated American Shoulder and Elbow Surgeons (ASES) shoulder assessment form and the Simple Shoulder Test (SST) in patients with shoulder arthritis.

METHODS

Fifty-two patients with the primary diagnosis of shoulder arthritis were asked to fill out the ASES, SST, and PROMIS PFUE CAT. The time for completion of each survey was measured to determine responder burden, and correlation between the 3 instruments was defined as excellent (>0.7), strong-moderate (0.61-0.7), moderate (0.31-0.6), and poor (0.2-0.3).

RESULTS

The PROMIS PFUE CAT showed a strong-moderate correlation with the SST (r = 0.64; P < .001) and a moderate correlation with the ASES (r = 0.57; P < .001). The average times to complete the SST, ASES, and PROMIS PFUE CAT were determined to be 96.9 ± 25.1 seconds, 160.6 ± 51.5 seconds, and 62.6 ± 22.8 seconds, respectively. The time to complete the PROMIS PFUE CAT was significantly less than the time to complete the SST (P < .001) and the ASES (P < .001).

CONCLUSION

In patients with shoulder arthritis, The PROMIS PFUE CAT demonstrated strong-moderate correlation with the SST and moderate correlation with the ASES. The time savings of the PROMIS PFUE CAT were small compared with the ASES and SST but demonstrate that moving forward, using the PROMIS PFUE CAT would not place any additional burden on the patient filling out the survey. These findings indicate that the PROMIS PFUE CAT is an appropriate measurement tool for patients with shoulder arthritis.

Validity and Responsiveness of the Pain Self-Efficacy Questionnaire in Patients With Neck Pain Disorders

Study Design Longitudinal clinimetric study. Background Pain self-efficacy predicts poor recovery and mediates the relationship between pain and disability in patients with neck pain disorders (NPDs). The Pain Self-Efficacy Questionnaire (PSEQ) is a frequently used instrument to measure pain self-efficacy; however, its measurement properties have never been evaluated in a group of patients with NPDs. Objectives This study aimed to assess validity and responsiveness of the PSEQ in patients with NPDs. Methods Patients with NPDs (n = 161) were included. Confirmatory and exploratory factor analysis was used to assess structural validity. Twelve hypotheses on expected correlations with other instruments were formulated a priori to assess construct validity. Responsiveness was evaluated in 146 patients with NPDs who underwent multimodal rehabilitation by testing 12 hypotheses on expected effect sizes, area under the curve, and correlations with change in other instruments. Results Factor analyses showed that the PSEQ is a unidimensional instrument with moderate construct validity and responsiveness (50% to 75% of hypotheses met). Validity was consistent when analyzed separately for patients with whiplash-associated disorders and idiopathic neck pain, and responsiveness was better in patients with idiopathic neck pain. Conclusion The PSEQ is a unidimensional measure of pain self-efficacy in patients with NPDs, as found by previous studies in other populations. Nevertheless, in contrast with previous studies, its construct validity and responsiveness were found to be suboptimal in NPDs, suggesting that the content validity of the PSEQ and of the comparator instruments used in this study should be better assessed. J Orthop Sports Phys Ther 2018;48(3):204-216. Epub 19 Dec 2017. doi:10.2519/jospt.2018.7605.

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.

Patient Reported Outcomes Measurement Information System (PROMIS) in the upper extremity: the future of outcomes reporting?

Patient reported outcomes (PROs) serve an integral role in clinical research by helping to determine the impact of clinical care as experienced by the patient. With recent initiatives in health care policy and pay for performance, outcome reporting is now recognized as a policy-driven requirement in addition to a clinical research tool. For outcome measures to satisfy these regulatory requirements and provide value in understanding disease outcomes, they must be responsive and efficient. Recent research has uncovered certain concerns regarding traditional PROs in patients with upper extremity disability and injury. These include lack of consensus regarding selection of PROs for a given diagnoses, inconsistent techniques of administration of the same PROs, and the administrative burden to patients and providers of completing these forms. To address these limitations, emphasis has been placed on streamlining the outcomes reporting process, and, as a result, the National Institutes of Health (NIH) created the Patient Reported Outcomes Measurement Information System (PROMIS). PROMIS forms were created to comprehensively and efficiently measure outcomes across multiple disease states, including orthopedics. These tools exist in computer adaptive testing and short forms with the intention of more efficiently measuring outcomes compared with legacy PROs. The goals of this review are to highlight the main components of PROMIS reporting tools and identify recent use of the scores in the upper extremity literature. The review will also highlight the research and health policy potentials and limitations of implementing PROMIS into everyday orthopedic practice.

The Accuracy of Computerized Adaptive Testing in Heterogeneous Populations: A Mixture Item-Response Theory Analysis

BACKGROUND

Computerized adaptive testing (CAT) utilizes latent variable measurement model parameters that are typically assumed to be equivalently applicable to all people. Biased latent variable scores may be obtained in samples that are heterogeneous with respect to a specified measurement model. We examined the implications of sample heterogeneity with respect to CAT-predicted patient-reported outcomes (PRO) scores for the measurement of pain.

METHODS

A latent variable mixture modeling (LVMM) analysis was conducted using data collected from a heterogeneous sample of people in British Columbia, Canada, who were administered the 36 pain domain items of the CAT-5D-QOL. The fitted LVMM was then used to produce data for a simulation analysis. We evaluated bias by comparing the referent PRO scores of the LVMM with PRO scores predicted by a "conventional" CAT (ignoring heterogeneity) and a LVMM-based "mixture" CAT (accommodating heterogeneity).

RESULTS

The LVMM analysis indicated support for three latent classes with class proportions of 0.25, 0.30 and 0.45, which suggests that the sample was heterogeneous. The simulation analyses revealed differences between the referent PRO scores and the PRO scores produced by the "conventional" CAT. The "mixture" CAT produced PRO scores that were nearly equivalent to the referent scores.

CONCLUSION

Bias in PRO scores based on latent variable models may result when population heterogeneity is ignored. Improved accuracy could be obtained by using CATs that are parameterized using LVMM.

Report of the NIH Task Force on Research Standards for Chronic Low Back Pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific, and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. The NIH Pain Consortium therefore charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimal data set to describe research participants (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The RTF believes these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. We expect the RTF recommendations will become a dynamic document, and undergo continual improvement.

PERSPECTIVE

A Task Force was convened by the NIH Pain Consortium, with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimal dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Health-related profiles of people with lower limb loss

OBJECTIVES

To construct profiles of self-reported health indicators to examine differences and similarities between people with lower limb loss and a normative sample (hereafter called the norm) and to compare health indicators between subgroups based on level and etiology of limb loss.

DESIGN

Survey.

SETTING

General community.

PARTICIPANTS

Adults with unilateral lower limb loss (N=1091) participated in this study. Eligibility criteria included lower limb loss due to trauma or dysvascular complications and regular use of a prosthesis.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The Patient-Reported Outcomes Measurement Information System 29-item Health Profile version 1.0 measures physical function, pain interference, fatigue, sleep disturbance, anxiety, depression, and satisfaction with participation in social roles. The norm includes 5239 individuals representative of the U.S. general population in sex, age, race, ethnicity, and education.

RESULTS

People with lower limb loss reported statistically significantly worse physical function, pain interference, and satisfaction with participation in social roles and significantly less fatigue than did the norm. People with transfemoral (ie, above-knee) amputation significantly differed in physical function from people with transtibial (ie, below-knee) amputation. Similarly, people with amputation due to trauma and dysvascular etiology significantly differed in physical function and satisfaction with social roles after adjusting for relevant clinical characteristics.

CONCLUSIONS

People with lower limb loss generally report worse physical function, pain interference, and satisfaction with social roles than do the norm. People with dysvascular amputation reported worse physical function and satisfaction with social roles than did people with traumatic amputation. Health indicator profiles are an efficient way of providing clinically meaningful information about numerous aspects of self-reported health in people with lower limb loss.

Report of the NIH Task Force on research standards for chronic low back pain

OBJECTIVE

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific, and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus.

DESIGN

Expert panel and preliminary evaluation of key recommendations.

METHODS

The NIH Pain Consortium charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel developed a 3-stage process, each with a 2-day meeting.

RESULTS

The panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimal data set to describe research subjects (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals.

CONCLUSION

The RTF believes these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes. We expect the RTF recommendations will become a dynamic document, and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimum dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

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.

Report of the NIH Task Force on research standards for chronic low back pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. Therefore, NIH Pain Consortium charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimum dataset to describe research participants (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. We expect that the RTF recommendations will become a dynamic document and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimum dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Focus article: report of the NIH Task Force on Research Standards for Chronic Low Back Pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. Therefore, NIH Pain Consortium charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimum dataset to describe research participants (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. We expect that the RTF recommendations will become a dynamic document and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimum dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Physical therapists' level of McKenzie education, functional outcomes, and utilization in patients with low back pain

STUDY DESIGN

Longitudinal, prospective, observational cohort.

OBJECTIVE

To examine associations between McKenzie training, functional status (FS) at discharge, and number of physical therapy visits (utilization) in patients receiving physical therapy for low back pain.

BACKGROUND

The McKenzie method is commonly used in treating patients with low back pain.

METHODS

A McKenzie postgraduate educational program was initiated in a large outpatient physical therapy service. Functional status data were collected at intake and at discharge. Separate hierarchical linear mixed models were used to examine associations between physical therapists' McKenzie training level (none; Parts A, B, C, and D; and credentialed), FS score at discharge, and utilization, controlling for patient risk factors.

RESULTS

The final data set included 20 882 patients (mean ± SD age, 51 ± 16 years; 57% women) who completed FS surveys at both admission and discharge. Patients treated by physical therapists with any McKenzie training had better outcomes (additional 0.7 to 1.3 FS points; P<.05 to <.001) and fewer visits (0.6 to 0.9, P<.001) compared to patients treated by physical therapists with no training. For patients treated by therapists with no versus some McKenzie education, 65% versus 70% achieved at least the minimal clinically important improvement, respectively. There were no significant differences in outcomes or utilization by level of McKenzie training.

CONCLUSION

There was a slightly greater improvement of 0.7 to 1.3 points in FS at discharge in patients receiving physical therapy for low back pain by physical therapists who underwent McKenzie training. This difference was clinically important for an additional 5% of patients who achieved the minimal clinically important improvement when treated by therapists with some McKenzie training. Reduction in physical therapy utilization was 0.6 to 0.9 visits, with the fewest visits utilized by patients of physical therapists at the McKenzie Part D and credentialed levels. Together, these findings suggest improved cost-effectiveness at advanced McKenzie training levels. Ways to improve ongoing education and patient outcomes were proposed.

Report of the National Institutes of Health task force on research standards for chronic low back pain

OBJECTIVES

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed nonspecific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. The purpose of this article is to disseminate the report of the National Institutes of Health (NIH) task force on research standards for cLBP.

METHODS

The NIH Pain Consortium charged a research task force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel developed a 3-stage process, each with a 2-day meeting.

RESULTS

The panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimal data set to describe research subjects (drawing heavily on the Patient Reported Outcomes Measurement Information System methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved these recommendations, which investigators should incorporate into NIH grant proposals.

CONCLUSIONS

The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of cLBP. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes. We expect the RTF recommendations will become a dynamic document and undergo continual improvement.

Report of the NIH Task Force on Research Standards for Chronic Low Back Pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. Therefore, NIH Pain Consortium charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimum dataset to describe research participants (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. We expect that the RTF recommendations will become a dynamic document and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimum dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Report of the NIH task force on research standards for chronic low back pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed nonspecific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. Therefore, NIH Pain Consortium charged a research task force to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimum data set to describe research participants (drawing heavily on the Patient Reported Outcomes Measurement Information System methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The research task force believes that these recommendations will advance the field, help resolve controversies, and facilitate future research addressing the genomic, neurological, and other mechanistic substrates of cLBP. We expect that the research task force recommendations will become a dynamic document and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for cLBP. The results included recommendations for definitions, a minimum data set, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Report of the NIH Task Force on research standards for chronic low back pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. Therefore, NIH Pain Consortium charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimum dataset to describe research participants (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. We expect that the RTF recommendations will become a dynamic document and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimum dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Telephone interviews and online questionnaires can be used to improve neurodevelopmental follow-up rates

Background

Maximising response rates to neurodevelopmental follow-up is a key challenge for paediatric researchers. We have investigated the use of telephone interviews and online questionnaires to improve response rates, reduce non-response bias, maintain data completeness and produce unbiased outcomes compared with postal questionnaires when assessing neurodevelopmental outcomes at 2 years.

Methods

A prospective cohort study of babies born ≥32 weeks gestation. Neurodevelopmental outcomes were assessed at 2 years of age using a parent questionnaire completed via post, telephone or online. Relative Risks with 95% confidence intervals (RR; 95% CI) were calculated to identify participant characteristics associated with non-response and questionnaire response mode (postal vs. telephone/online). The proportion of missing data and prevalence of adverse outcomes was compared between response modes using generalized linear models.

Results

Offering telephone/online questionnaires increased the study response rate from 55% to 60%. Telephone/online responders were more likely to be non-white (RR 1.6; [95% CI 1.1, 2.4]), non-English speaking (1.6; [1.0, 2.6]) or have a multiple birth (1.6; [1.1, 2.3]) than postal responders. There were no significant differences in the prevalence of adverse neurodevelopmental outcomes between those who responded via post vs. telephone/online (1.1; [0.9, 1.4]). Where parents attempted all questionnaire sections, there were no significant differences in the proportion of missing data between response modes.

Conclusions

Where there is sufficient technology and resources, offering telephone interviews and online questionnaires can enhance response rates and improve sample representation to neurodevelopmental follow-up, whilst maintaining data completeness and unbiased outcomes.

Lumbar computerized adaptive test and Modified Oswestry Low Back Pain Disability Questionnaire: relative validity and important change

STUDY DESIGN

Retrospective analysis of longitudinal, observational cohort data.

OBJECTIVES

To compare discriminating ability and minimal clinically important improvement (MCII) calculated using functional status (FS) measures estimated from the lumbar computerized adaptive test (LCAT) and Modified Oswestry Low Back Pain Disability Questionnaire (ODQ).

BACKGROUND

The LCAT and ODQ are commonly used to estimate FS in patients seeking outpatient therapy but have not been compared directly.

METHODS

Data from 8198 adult patients who completed the LCAT and ODQ at intake were analyzed, 3379 (41%) of whom completed both surveys at discharge. Global ratings of change data were available for 980 patients. Discriminating ability of FS estimates from the LCAT and ODQ was estimated using relative validity, calculated by dividing F values from LCAT and ODQ analyses of covariance for important risk-adjustment variables. MCII was estimated using receiver-operating-characteristic analyses by quartiles of intake FS values, and areas under the curves were compared.

RESULTS

Relative validity ratios favored the LCAT for age (3.7; 95% confidence interval [CI]: 2.0, 8.9), acuity (1.3; 95% CI: 1.1, 1.6), comorbidities (1.8; 95% CI: 1.3, 2.6), and surgical history (1.8; 95% CI: 1.2, 2.9). MCII cut scores per quartile favored the LCAT. Receiver-operating-characteristic areas under the curves were not different.

CONCLUSION

FS measures estimated by both questionnaires had similar psychometric characteristics. The LCAT FS estimates tended to be more discriminating than ODQ FS estimates. MCII cut scores by quartile of intake FS favored the LCAT. Given the need to be efficient and precise in estimating measures of FS, particularly in older patients, results favor the LCAT in busy, automated outpatient therapy clinics, which are increasingly serving an aging population.

Neuro-QOL: brief measures of health-related quality of life for clinical research in neurology

OBJECTIVE

To address the need for brief, reliable, valid, and standardized quality of life (QOL) assessment applicable across neurologic conditions.

METHODS

Drawing from larger calibrated item banks, we developed short measures (8-9 items each) of 13 different QOL domains across physical, mental, and social health and evaluated their validity and reliability. Three samples were utilized during short form development: general population (Internet-based, n = 2,113); clinical panel (Internet-based, n = 553); and clinical outpatient (clinic-based, n = 581). All short forms are expressed as T scores with a mean of 50 and SD of 10.

RESULTS

Internal consistency (Cronbach α) of the 13 short forms ranged from 0.85 to 0.97. Correlations between short form and full-length item bank scores ranged from 0.88 to 0.99 (0.82-0.96 after removing common items from banks). Online respondents were asked whether they had any of 19 different chronic health conditions, and whether or not those reported conditions interfered with ability to function normally. All short forms, across physical, mental, and social health, were able to separate people who reported no health condition from those who reported 1-2 or 3 or more. In addition, scores on all 13 domains were worse for people who acknowledged being limited by the health conditions they reported, compared to those who reported conditions but were not limited by them.

CONCLUSION

These 13 brief measures of self-reported QOL are reliable and show preliminary evidence of concurrent validity inasmuch as they differentiate people based upon number of reported health conditions and whether those reported conditions impede normal function.

Managing missing scores on the Roland Morris Disability Questionnaire

STUDY DESIGN

Analysis of Roland Morris Disability Questionnaire (RMDQ) and Oswestry Disability Index (Oswestry) responses.

OBJECTIVE

To determine the prevalence of unanswered questions on the RMDQ23 (23-item RMDQ version) and Oswestry questionnaires. To determine whether managing RMDQ23 missing data using proportional recalculation is more accurate than simply ignoring missing data.

SUMMARY OF BACKGROUND DATA

It is likely that the most common method for calculating an RMDQ sum score is to simply ignore any unanswered questions. In contrast, the raw sum score on the Oswestry is converted to a 0 to 100 scale, with the advantage of allowing missing data to be accommodated by proportional recalculation.

METHODS

The prevalence of unanswered RMDQ23 questions was measured in a research project and a routine care setting. The accuracy of the RMDQ23 proportional recalculation method was measured using 311 fully completed RMDQ23 and matching Oswestry questionnaire sets. Raw sum scores were calculated, and questions systematically dropped. At each stage, sum scores were converted to a score on a 0 to 100 scale and the error calculated. Wilcoxon Tests were used to compare the magnitude of the error scores.

RESULTS

The prevalence of people who did not answer one or more questions was 29.5% (RMDQ23) in routine care, and 13.9% (Oswestry) and 20.3% (RMDQ23) in a research project. Proportional recalculation was a more accurate method to calculate RMDQ sum scores than simply ignoring missing data, when two or more questions were unanswered.

CONCLUSION

Because of less error when missing data are present, the most accurate method for expressing RMDQ sum scores collected using Yes/No answers is conversion to a 0 to 100 scale. This conversion method is (a) if all questions are answered or only one question is unanswered, multiply the raw sum score by 100 divided by the total number of questions, and (b) if two or more questions are unanswered, multiply the raw sum score by 100 divided by the number of answered questions.

Telephone interviews can be used to collect follow-up data subsequent to no response to postal questionnaires in clinical trials

OBJECTIVE

Follow-up data were collected using postal questionnaires and if participants did not respond, then data was collected using telephone interviews. The objectives of this study were to examine, for the two methods, how respondents differed in characteristics and whether the observed treatment difference varied.

STUDY DESIGN AND SETTING

A large clinical trial of lower back pain.

RESULTS

About 60% (98/163) of the nonresponders to postal questionnaire provided data by telephone, which increased the overall response rate by 14% (from 71% to 85%). A consistent treatment difference was found across the methods for the outcome measures at 12 months, implying that the observed treatment effect had not been modified. There were some differences between the participants: responders of postal questionnaire were older, likely to be female, white (ethnic origin), not working, with less disability of back pain, compared with those who responded by a telephone interview. At 12 months, there was greater improvement in back pain, disability, and general health for those who responded by postal questionnaires.

CONCLUSION

Researchers should consider the use of more than one method of collecting data as this increases response rate, participant representativeness, and enhances precision of effect estimates.

Cross-cultural differences in knee functional status outcomes in a polyglot society represented true disparities not biased by differential item functioning

BACKGROUND

Comparative effectiveness research across cultures requires unbiased measures that accurately detect clinical differences between patient groups.

OBJECTIVE

The purpose of this study was to assess the presence and impact of differential item functioning (DIF) in knee functional status (FS) items administered using computerized adaptive testing (CAT) as a possible cause for observed differences in outcomes between 2 cultural patient groups in a polyglot society.

DESIGN

This study was a secondary analysis of prospectively collected data.

METHODS

We evaluated data from 9,134 patients with knee impairments from outpatient physical therapy clinics in Israel. Items were analyzed for DIF related to sex, age, symptom acuity, surgical history, exercise history, and language used to complete the functional survey (Hebrew versus Russian).

RESULTS

Several items exhibited DIF, but unadjusted FS estimates and FS estimates that accounted for DIF were essentially equal (intraclass correlation coefficient [2,1]>.999). No individual patient had a difference between unadjusted and adjusted FS estimates as large as the median standard error of the unadjusted estimates. Differences between groups defined by any of the covariates considered were essentially unchanged when using adjusted instead of unadjusted FS estimates. The greatest group-level impact was <0.3% of 1 standard deviation of the unadjusted FS estimates.

LIMITATIONS

Complete data where patients answered all items in the scale would have been preferred for DIF analysis, but only CAT data were available.

CONCLUSIONS

Differences in FS outcomes between groups of patients with knee impairments who answered the knee CAT in Hebrew or Russian in Israel most likely reflected true differences that may reflect societal disparities in this health outcome.

Computerized adaptive test for patients with lumbar spine impairments produced valid and responsive measures of function

STUDY DESIGN

Outcomes instrument validation study.

OBJECTIVE

We evaluated administrative efficiency and psychometric adequacy of a computerized adaptive test (CAT) for patients with lumbar spine impairments seeking rehabilitation in outpatient therapy clinics.

SUMMARY OF BACKGROUND DATA

CATs promise efficient outcomes data collection in clinical applications with little loss of measurement precision compared to paper and pencil surveys. The lumbar CAT has been developed and simulated and is currently used routinely in therapy clinics. The CAT has not been assessed for administrative efficiency, and the outcomes measures estimated using the CAT have not been assessed using prospective data collection for validity, sensitivity to change, or responsiveness.

METHODS

Data from 17,439 patients with lumbar spine impairments receiving outpatient rehabilitation in 377 clinics in 30 states (United States) were analyzed. We evaluated efficiency of routine CAT administration and assessed construct validity, sensitivity to change, and responsiveness of CAT measures of lumbar functional status (FS).

RESULTS

On average, patients took less than 2 minutes (standard deviation <1 minute) to answer 7 CAT items (standard deviation, 3), which produced precise estimates of FS that adequately covered the content range with negligible floor and ceiling effects. Patients who were older had more chronic symptoms, had more surgeries, had more comorbidities, and did not exercise before receiving rehabilitation reported worse discharge FS. A total of 66% of patients obtained statistically significant change (95% confidence interval minimal detectable change) at discharge. Change of 5 FS units (scale, 0-100) represented minimal clinically important improvement, which 70% of patients obtained. Minimal detectable change and minimal clinically important improvement were associated with intake FS.

CONCLUSION

We concluded the lumbar CAT administration was efficient, and CAT FS measures were precise, valid, sensitive, and responsive, supporting lumbar CAT use in clinical and research applications.

Differential item functioning was negligible in an adaptive test of functional status for patients with knee impairments who spoke English or Hebrew

OBJECTIVE

We examined the presence and impact of differential item functioning (DIF) in a set of knee-specific functional status (FS) items administered using computerized adaptive testing (CAT) among English (United States) and Hebrew (Israel) speaking patients receiving therapy for knee impairments. DIF occurs in an item if probabilities of endorsing responses differ across groups after controlling for the FS measured.

METHODS

We analyzed data from 28,320 patients (14,160 U.S., 14,160 Israel) who completed the knee-specific CAT. Items were assessed for DIF by gender, age, symptom acuity, surgical history, exercise history, and language spoken using a hybrid technique that combines multiple ordinal logistic regression and item response theory FS estimates.

RESULTS

Several items had non-uniform DIF for covariates including language, but unadjusted and DIF-adjusted functional status estimates were in strong concordance [ICC(2,1) values >/=0.97], and differences between unadjusted and adjusted FS scores represented <0.4% of the unadjusted FS standard deviation.

CONCLUSIONS

Statistically significant DIF was identified in some items but represented negligible clinical impact. Results suggested no need to adjust items for DIF when assessing FS outcomes across groups of patients with knee impairments who answer the knee CAT items in English in the United States or Hebrew in Israel. These findings suggest negligible differences in cultural perceptions between English and Hebrew wording of these knee-specific CAT FS items.