A computerized adaptive test for patients with hip impairments produced valid and responsive measures of function

Upper Quadrant Edema Patient-Reported Outcome Measure Is Reliable, Valid, and Efficient for Patients With Lymphatic and Venous Disorders

OBJECTIVE

The main aims of this study were to (1) create a patient-reported outcome measure (PROM) item bank for measuring the impact of upper quadrant edema (UQE) on physical function by calibrating responses to newly developed items; and (2) assess reliability, validity, and administration efficiency of scores based on computerized adaptive test (CAT) and 10-item short-form (SF) administration modes.

METHODS

This was a retrospective study including data from patients treated in outpatient rehabilitation clinics for UQE that responded to all 27 candidate items at intake. Item response theory model assumptions of unidimensionality, local item independence, item fit, and presence of differential item functioning were evaluated. UQE-CAT- and UQE-SF-generated scores were assessed for reliability, validity, and administration efficiency.

RESULTS

The total cohort included 3486 patients (mean [SD] age = 61 [13] years; range = 14-89 years). After removing 2 items, a 25-item solution was supported for its unidimensionality and fit to the item response theory model with reliability estimates of more than 0.93 for scores based on both CAT and SF administration modes. No items demonstrated differential item functioning. Scores discriminated among multiple patient groups in clinically logical ways and were moderately responsive to change with negligible floor and acceptable ceiling effects. CAT scores were generated using an average of 5.6 items (median = 5).

CONCLUSION

Scores on the UQE PROM were reliable, valid, and efficient for assessing perceived physical function of patients with upper quadrant edema; thus, the measure is suitable for research and routine clinical administration.

IMPACT

The newly developed UQE PROM is reliable and valid and offers efficient administration modes for assessing perceived physical function of patients with UQE caused by lymphatic and venous disorders, both for research and routine clinical care in busy outpatient rehabilitation settings. As an item response theory-based measure, the UQE PROM allows administration of condition-specific functional questions with low response burden for patients. This study supports a transition to PROMs that are based on modern measurement approaches to achieve high accuracy and efficiency.

The Lower Extremity Physical Function Patient-Reported Outcome Measure Was Reliable, Valid, and Efficient for Patients With Musculoskeletal Impairments

OBJECTIVE

To calibrate the Lower Extremity Functional Scale (LEFS) items into a regional lower extremity physical function (LEPF) item bank and assess reliability, validity, and efficiency of computerized adaptive test (CAT) and short form (SF) administration modes.

DESIGN

Retrospective cohort.

SETTING

Data were collected from patients treated in outpatient rehabilitation clinics for musculoskeletal impairments of the hip, knee, foot, and ankle that responded to all 20 LEFS items at intake.

PARTICIPANTS

Patients aged 14 years or older who started an episode of care during January 2016-October 2019 and identified the lower extremity region as the source of a primary musculoskeletal complaint. Total cohort included 78,186 patients (mean age, 53±19y, range, 14-89y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Item response theory (IRT) model assumptions of unidimensionality, local item independence, item fit, and presence of differential item functioning (DIF) were studied. LEPF-CAT- and LEPF-SF-generated scores were evaluated.

RESULTS

An 18-item solution was supported for its unidimensionality and fit to the IRT model, with reliability estimates >0.9 for all administration modes. No DIF impact on LEPF scores was identified. Scores discriminated between multiple patient groups in clinically logical ways and were highly responsive to change, with negligible floor or ceiling effects. CAT scores were generated using an average of 4.9 items (median, 4).

CONCLUSIONS

The LEPF scores were reliable, valid, and efficient for assessing perceived physical function of patients with musculoskeletal impairments of the hip, knee, foot, and ankle; thus, it was found suitable for research and routine clinical administration. These findings are limited to the type of patients included in this study, with further validation needed to assess their generalizability.

Clinical Interpretation of the Neck Functional Status Computerized Adaptive Test

BACKGROUND

Clinical interpretation of patient-reported outcome measures is an essential step in patient-centered care. Interpretation of scores derived from the Neck Functional Status Computerized Adaptive Test (NFS-CAT) has not been studied.

OBJECTIVES

To (1) assess the reliability of point estimates and improvement scores, (2) determine thresholds of minimal clinically important improvement (MCII), and (3) develop a functional staging model to facilitate clinical interpretation of NFS-CAT scores.

METHODS

A secondary retrospective cohort analysis was performed using data from patients aged 14 to 89 years who started an episode of care for neck impairments during 2016-2017 and completed the NFS-CAT at admission. The reliability of point estimates and of improvement scores was derived from the NFS-CAT standard error of measurement. The MCII was estimated by combining distribution- and anchor-based approaches. A functional staging model was developed to describe clinical meaningfulness of the quantitative scores provided by the NFS-CAT.

RESULTS

Of 250 741 patients who completed the NFS-CAT at admission (mean ± SD age, 54 ± 16 years; 65% female), 169±039 (67%) also completed the NFS-CAT at discharge. The standard error of measurement was stable across the measurement continuum, ranging from 3.7 to 3.9 NFS-CAT points. Minimal detectable improvement was 6.8 points at the 90% confidence level. The estimate of the MCII was 8.1 points, with more change points needed to achieve the MCII for patients with lower baseline scores. Large rates of functional staging change during treatment were observed, demonstrating responsiveness of the functional staging model.

CONCLUSION

This study demonstrated how the NFS-CAT can be interpreted to better assist clinicians and patients with neck impairments during outpatient rehabilitation.

LEVEL OF EVIDENCE

Therapy, level 2b. J Orthop Sports Phys Ther 2019;49(12):875-886. Epub 10 Jul 2019. doi:10.2519/jospt.2019.8862.

Astym® therapy improves FOTO® outcomes for patients with musculoskeletal disorders: an observational study

Background

Current healthcare providers function in an environment where there is increased emphasis on value-based models of reimbursement; therefore, the delivery of better patient outcomes is critical. Consequently, it is necessary to identify successful treatments that improve outcomes and can be applied across a broad range of clinic settings, treatment styles and therapist expertise.

Methods

Data from 2,450 patients who received Astym therapy as component of their outpatient rehabilitation (treatment group) was matched to data from 2,450 randomly chosen patients with similar orthopedic impairments who did not receive Astym therapy during their rehabilitation (control group). Data was collected across 116 clinics in 17 U.S. states. All patients completed a standardized functional status survey at admission and at discharge. The effectiveness (discharge functional status score), efficiency (number of treatment visits, treatment duration) and utilization (unit of functional improvement per visit) was compared across two groups. Ethics approval was not required for this study as this is an observational study, with both sets of participants receiving actual (not placebo) treatment.

Results

Compared to the control sample, patients who received Astym therapy as part of their rehabilitation had higher discharge functional status (FS) scores (68.5 vs. 64.5, F_1,4897 =53.1, P<0.001) and had more functional improvement per visit noted with a higher utilization index (2.0 vs. 1.9, ANCOVA F_1,4897 =5.5, P=0.019), and after risk adjustment, had the same number of visits. There was no difference in duration of treatment episode across groups (Astym, 47.8±31.1 days; control, 47.5±30.0 days) (ANCOVA F_1,4897 =1.7, P=0.199).

Conclusions

Patients with musculoskeletal disorders who received Astym therapy as part of the treatment process experienced increased treatment effectiveness as compared to those who did not receive Astym therapy. The addition of Astym therapy improved physical therapy outcomes for patients across a broad range of treatment styles, clinical settings and therapist expertise.

Calibration and validation of an item bank for measuring general physical function of patients in medical rehabilitation settings

Objective

The objective of this study was to report the item response theory (IRT) calibration of an 18-item bank to measure general physical function (GPF) in a wide range of conditions and evaluate the validity of the derived scores.

Methods

All 18 items were administered to a large sample of patients (n=2337) who responded to the items in the context of their outpatient rehabilitation care. The responses, collected 1997– 2000, were modeled using the graded response model, an IRT model appropriate for items with two or more response options. Inter-item consistency was evaluated based on Cronbach’s alpha and item to total correlations. Validity of scores was evaluated based on known-groups comparisons (age, number of health problems, symptom severity). The strength of a single, general factor was evaluated using a bi-factor model. Results were used to evaluate IRT assumption and as an indicator of construct validity. Local independence of item responses was also evaluated.

Results

Response data met the assumptions of unidimensionality and local independence. Explained common variance of a single general factor was 0.88 (omega hierarchical =0.86). Only two of the 153 pairs of item residuals were flagged for local dependence. Inter-item consistency was high (0.93) as were item to total correlations (mean =0.61). Substantial variation was found in both IRT location (difficulty) and discrimination parameters. All omnibus known-groups comparisons were statistically significant (p<0.001).

Conclusion

Item responses fit the IRT unidimensionality assumptions and were internally consistent. The usefulness of GPF scores in discriminating among patients with different levels of physical function was confirmed. Future studies should evaluate the validity of GPF scores based on an adaptive administration of items.

Considerations and recommendations for selection and utilization of upper extremity clinical outcome assessments in human spinal cord injury trials

Study design

This is a focused review article.

Objectives

This review presents important features of clinical outcomes assessments (COAs) in human spinal cord injury research. Considerations for COAs by trial phase and International Classification of Functioning, Disability and Health are presented as well as strengths and recommendations for upper extremity COAs for research. Clinical trial tools and designs to address recruitment challenges are identified.

Methods

The methods include a summary of topics discussed during a two-day workshop, conceptual discussion of upper extremity COAs and additional focused literature review.

Results

COAs must be appropriate to trial phase and particularly in mid-late-phase trials, should reflect recovery vs. compensation, as well as being clinically meaningful. The impact and extent of upper vs. lower motoneuron disease should be considered, as this may affect how an individual may respond to a given therapeutic. For trials with broad inclusion criteria, the content of COAs should cover all severities and levels of SCI. Specific measures to assess upper extremity function as well as more comprehensive COAs are under development. In addition to appropriate use of COAs, methods to increase recruitment, such as adaptive trial designs and prognostic modeling to prospectively stratify heterogeneous populations into appropriate cohorts should be considered.

Conclusions

With an increasing number of clinical trials focusing on improving upper extremity function, it is essential to consider a range of factors when choosing a COA.

Sponsors

Craig H. Neilsen Foundation, Spinal Cord Outcomes Partnership Endeavor.

Item Response Theory and Computerized Adaptive Testing for Orthopaedic Outcomes Measures

The use of patient-reported outcome measures (PROMs) to objectively and quantifiably assess patient symptomatology allows tracking of symptoms over time, measurement of the effect of healthcare interventions, and performance of cost-effectiveness analyses to assess and compare the value of treatment options. Many of the PROMs historically used had limited versatility because they were developed using classical test theory, which generates static tests that are not comparable with other measures assessing similar outcomes. Recently developed PROMs, however, were designed according to the principles of the newer item response theory (IRT), which allows for the creation of dynamic instruments deliverable in a variety of forms that are readily comparable with similar measures. IRT also enables computerized adaptive testing to decrease the burden of using PROMs by allowing rapid and complete data acquisition. IRT-based instruments are suitable for patient care and research and have been validated in a variety of populations, many of which are relevant to orthopaedic populations.

Evaluation of Computerized Adaptive Tests (CATs) for longitudinal monitoring of depression, anxiety, and stress reactions

BACKGROUND

Computerized adaptive testing (CAT) based on Item Response Theory, (IRT) offers an efficient way for accurate measurement of patient reported outcomes. The efficiency lies within a minimal response burden and a high measurement precision over a broad measurement range. The objective of the study was to evaluate and compare the responsiveness of CATs measuring anxiety, depression, and stress reaction to standard static self-assessment tools.

METHODS

Longitudinal data of n=595 psychosomatic inpatients were analyzed for evaluating retest-reliability and sensitivity to change of the CATs compared to static measures (GAD-7, PHQ-9, and PSQ) using correlational and ANOVA statistics. The study hypothesized that CATs are at least as retest-reliable and as sensitive to change as static tools.

RESULTS

The three CATs show a low burden for patients, administering on average 5-7 (±2-6SD) items with similar retest-reliability compared to the static tools applied (A-CAT: r=.78 vs. GAD-7: r=.75, D-CAT: r=.71 vs. PHQ-9: r=.75, S-CAT: r=.80 vs. PSQworries scale: r=.80). The CATs were overall as sensitive to change as the static tools (Cohen׳s d ranged between .19 and .69).

LIMITATIONS

This is a monocenter, observational, longitudinal study without external clinical criteria; thus generalization to other settings may be limited.

CONCLUSIONS

The tested CATs belong to the first generation of CATs being used in daily routine for more than a decade. They are as retest reliable and sensitive to change as static tools. Newer CATs may provide further practical advantages.

The Development and Psychometric Properties of the Patient Self-Report Neck Functional Status Questionnaire (NFSQ)

STUDY DESIGN

Retrospective analysis of cross-sectional data.

OBJECTIVE

To describe the development of a new self-report Neck Functional Status Questionnaire (NFSQ) and to assess its psychometric properties and practical application. The NFSQ was designed to assess functional status in patients with cervical (spine) disorders who seek outpatient therapy.

BACKGROUND

Many patients seek outpatient therapy due to cervical disorders. Currently, no patient-reported outcome measures exist that capture the ability to perform functional activity in a manner that reflects the experience of this patient population.

METHODS

Four hundred thirty-nine patients who were being treated for cervical disorders responded to a set of survey questions to assess activity-related functional outcomes associated with cervical disorders. Using item response theory, we assessed candidate items for unidimensionality and local independence, item fit, person separation, precision, targeting, and differential item functioning. We also compared discriminant validity of functional status measures estimated by the item response theory model (NFSQ fixed) and measures generated using a simulated computerized adaptive test (NFSQ computerized adaptive test).

RESULTS

Based on expert opinion and subsequent processing and analyses, a final set of 28 items was used to develop the NFSQ. Unidimensionality and local independence were supported. The mean ± SD sample ability level of 57.6 ± 14.3 (scale range, 0-100) matched well with the mean item difficulty of the NFSQ of 51.3 ± 7.4. Differential item functioning was negligible for levels of age group, sex, and symptom acuity. The NFSQ computerized adaptive test measures were as precise as the NFSQ fixed measures.

CONCLUSION

Study results supported the preliminary validity of the 28-item NFSQ for use in assessing patients with different levels of functional status related to their cervical disorders in outpatient rehabilitation settings.

Benchmarking Outpatient Rehabilitation Clinics Using Functional Status Outcomes

OBJECTIVE

To utilize functional status (FS) outcomes to benchmark outpatient therapy clinics.

DATA SOURCES

Outpatient therapy data from clinics using Focus on Therapeutic Outcomes (FOTO) assessments.

STUDY DESIGN

Retrospective analysis of 538 clinics, involving 2,040 therapists and 90,392 patients admitted July 2006-June 2008. FS at discharge was modeled using hierarchical regression methods with patients nested within therapists within clinics. Separate models were estimated for all patients, for those with lumbar, and for those with shoulder impairments. All models risk-adjusted for intake FS, age, gender, onset, surgery count, functional comorbidity index, fear-avoidance level, and payer type. Inverse probability weighting adjusted for censoring.

DATA COLLECTION METHODS

Functional status was captured using computer adaptive testing at intake and at discharge.

PRINCIPAL FINDINGS

Clinic and therapist effects explained 11.6 percent of variation in FS. Clinics ranked in the lowest quartile had significantly different outcomes than those in the highest quartile (p < .01). Clinics ranked similarly in lumbar and shoulder impairments (correlation = 0.54), but some clinics ranked in the highest quintile for one condition and in the lowest for the other.

CONCLUSIONS

Benchmarking models based on validated FS measures clearly separated high-quality from low-quality clinics, and they could be used to inform value-based-payment policies.

The impact of physical therapy residency or fellowship education on clinical outcomes for patients with musculoskeletal conditions

STUDY DESIGN

A retrospective cohort design was conducted using data from an electronic survey and an existing commercial outcomes database.

OBJECTIVE

To compare the clinical outcomes of patients with musculoskeletal conditions treated by physical therapists who had completed residency or fellowship programs versus those who had not.

BACKGROUND

There is an increasing focus on specialization through postprofessional education in physical therapy residency and fellowship programs. Scant evidence exists that evaluates the influence of postprofessional clinical education on actual patient outcomes.

METHODS

Physical therapists using a national outcomes database were surveyed to determine their level of postprofessional education. Survey responders were categorized into 1 of 3 groups that included no residency or fellowship training, residency trained, or fellowship trained. Outcomes for 25 843 patients with musculoskeletal conditions treated by 363 therapists from June 2012 to June 2013 were extracted from the database. These data were analyzed to identify any differences in functional status change and efficiency achieved between the 3 groups. Potentially confounding variables were controlled for statistically.

RESULTS

The fellowship-trained group of physical therapists achieved functional status changes and efficiency that were greater than those of the other groups. No difference in functional status change was observed between the residency group and the therapists without residency or fellowship training. The group without residency or fellowship training was more efficient than the residency-trained group. Fellowship-trained therapists were more likely to achieve greater treatment effect sizes than therapists without residency or fellowship training. Residency-trained therapists were less likely to achieve greater treatment effect sizes than the therapists without residency or fellowship training.

CONCLUSION

These data demonstrate that fellowship training may contribute to statistically greater patient outcomes. Residency training did not appear to contribute to improved patient functional status change or efficiency. It is unknown whether the statistical differences observed would be clinically meaningful for patients.

Global ratings of change do not accurately reflect functional change over time in clinical practice

STUDY DESIGN

Retrospective longitudinal cohort study.

OBJECTIVES

To determine whether the global rating of change (GROC) is valid for assessing functional change over time in the clinical setting, and whether validity decreases as length of recall increases.

BACKGROUND

The validity of GROC instruments for representing change over time has been questioned. Our previous study showed that GROC did not adequately represent functional change over time in patients with knee disorders. This was a validation study in patients with hip or ankle/foot disorders.

METHODS

We obtained complete data from the Focus On Therapeutic Outcomes clinical database on episodes of care for 7341 patients with hip or ankle/foot disorders. Functional status (FS) was assessed at the intake and discharge physical therapy visits via computerized adaptive testing. Each patient's GROC was assessed at the discharge visit. We assessed the extent to which GROC was associated with intake, discharge, and change in FS using correlation and linear regression analyses, stratified by recall period and anatomical location.

RESULTS

Correlations of GROC with hip and ankle FS change scores were modest for recall less than 30 days and deteriorated further as the recall period lengthened. Prediction of GROC from discharge and change in FS scores by linear regression modeling demonstrated a decline of standardized beta coefficients and R2 values as the recall period lengthened. Regression analyses indicated that GROC was biased toward discharge FS, with little or no influence of intake FS.

CONCLUSION

These results confirm that GROC does not adequately or consistently correlate with functional change across varying lengths of time, and is therefore not recommended as a substitute for change scores on valid functional outcome measures for use in routine clinical practice.

Implications of practice setting on clinical outcomes and efficiency of care in the delivery of physical therapy services

STUDY DESIGN

Retrospective analysis of episodes of care.

OBJECTIVE

To assess the implications of practice setting (hospital outpatient settings versus private practice) on clinical outcomes and efficiency of care in the delivery of physical therapy services.

BACKGROUND

Many patients with musculoskeletal conditions benefit from care provided by physical therapists. The majority of physical therapists deliver services in either a private practice setting or in a hospital outpatient setting. There have not been any recent studies comparing whether clinical outcomes or efficiency of care differ based on practice setting.

METHODS

Practices that use the Focus On Therapeutic Outcomes, Inc system were surveyed to determine the specific type of setting in which outcomes were collected in patients with musculoskeletal impairments. Patient outcome data over 12 months (2011-2012) were extracted from the database and analyzed to identify differences in the functional status achieved and the efficiency of the care delivery process between private practices and hospital outpatient settings.

RESULTS

The data suggest that patients experience more efficient care when receiving physical therapy in hospital outpatient settings compared to private practice settings, as demonstrated by 3.1 points of greater improvement in functional status over 2.9 fewer physical therapy visits. However, the difference in improvement between settings is less than the minimum clinically important difference of 9 points in functional status outcome score.

CONCLUSION

In this cohort, our data suggest that more efficient care was delivered in the hospital outpatient setting compared to the private practice setting. However, we cannot conclude that care delivered in the hospital setting is more cost-effective, because it is possible that any difference in efficiency of care favoring the hospital outpatient setting is more than offset by higher costs of care.

Patient global ratings of change did not adequately reflect change over time: a clinical cohort study

BACKGROUND

Global ratings of change (GROCs) are commonly used in research and clinical practice to determine which patients respond to therapy, but their validity as a criterion for change has not been firmly established. One factor related to their validity is the length of the recall period.

OBJECTIVE

The study objective was to examine the influence of the length of the recall period on the validity of a GROC for determining true change over time in the clinical setting.

DESIGN

This was a longitudinal, single-cohort observational study.

METHODS

Data from the Focus on Therapeutic Outcomes clinical database were collected for 8,955 patients reporting for physical therapy treatment of a knee disorder. Computerized adaptive testing was used to assess knee functional status (FS) at the initial and final (discharge) physical therapy visits. Each patient's GROC was obtained at discharge. Correlation and linear regression analyses of knee FS and GROC, stratified by length of time between intake and discharge, were conducted.

RESULTS

Correlations of GROC with knee FS change scores were modest even for the shortest period of recall (0-30 days) and were slightly lower for longer recall periods. Regression analyses using knee FS to predict GROC scores revealed similar findings. Correlations of GROC with intake and discharge scores indicated a strong bias toward discharge status, with little or no influence of baseline status. Standardized regression coefficients fitted the pattern expected for a valid measure of change but confirmed the strong bias toward discharge status.

LIMITATIONS

One version of the GROC administered serially in a cohort of patients seen in clinical practice was examined.

CONCLUSIONS

These results call into question the validity of GROCs for measuring change over time in routine clinical practice.

The self-report fecal incontinence and constipation questionnaire in patients with pelvic-floor dysfunction seeking outpatient rehabilitation

BACKGROUND

Fecal incontinence and constipation affect men and women of all ages.

OBJECTIVE

The purpose of this study was to psychometrically analyze the Fecal Incontinence and Constipation Questionnaire (FICQ) in patients seeking outpatient rehabilitation services due to pelvic-floor dysfunction (PFD).

DESIGN

This was a retrospective analysis of cross-sectional data from 644 patients (mean age=52 years, SD=16, range=18-91) being treated for PFD in 64 outpatient rehabilitation clinics in 20 states (United States).

METHODS

We assessed the 20-item FICQ for unidimensionality and local independence, differential item functioning (DIF), item fit, item hierarchical structure, and test precision using an item response theory model.

RESULTS

Factor analyses supported the 2-factor subscales as originally defined; items related to severity of leakage or constipation. Removal of 2 leakage items improved unidimensionality and local independence of the leakage scale. Among the remaining items, 2 items were suggestive of adjustment for DIF by age group and by number of PFD comorbid conditions. Item difficulties were suitable for patients with PFD with no ceiling or floor effect. Mean item difficulty parameters for leakage and constipation subscales ranged from 38.8 to 62.3 and 28.1 to 63.3 (0-100 scale), respectively. Endorsed leakage items representing highest difficulty levels were related to delay defecation and confidence to control bowel leakage. Endorsed constipation items representing highest difficulty levels were related to the need to strain during a bowel movement and the frequency of bowel movements.

LIMITATIONS

A limitation of this study was the lack of medical diagnostic criteria to classify patients.

CONCLUSIONS

After removing 2 items and adjusting for DIF, the results supported sound psychometric properties of the FICQ items and its initial use for patients with PFD in outpatient rehabilitation services.

Characteristics of patients seeking outpatient rehabilitation for pelvic-floor dysfunction

BACKGROUND

Pelvic-floor dysfunction (PFD) affects a substantial proportion of individuals, especially women.

OBJECTIVE

The purposes of this study were: (1) to describe the characteristics of individuals with disorders associated with PFD who were seeking outpatient physical therapy services and (2) to identify the prevalence of specific pelvic-floor disorders in the group.

DESIGN

This was a prospective, longitudinal, cohort study of 2,452 patients (mean age=50 years, SD=16, range=18-91) being treated in 109 outpatient physical therapy clinics in 26 states (United States) for their PFD.

METHODS

This study examined patient demographic variables and summarized patient self-reported responses to questions related to urinary and bowel functioning at admission prior to receiving the therapy for their PFD disorders.

RESULTS

Patients primarily were female (92%), were under 65 years of age (39%: 18 to <45 years; 39%: 45 to <65 years; 21%: 65 years or older), and had chronic symptoms (74%). Overall, 67% of the patients reported that they had urinary problems, 27% reported bowel problems, and 39% had pelvic pain. Among those who had urinary or bowel disorders, 32% and 54% reported leakage and constipation, respectively, as their only problem. Among patients who had pelvic pain, most (56%) reported that the pain was in the abdominal area. Combinations of urinary, bowel, or pelvic-floor pain disorders occurred in 31% of the patients.

LIMITATIONS

Because this study was a secondary analysis of data collected prospectively, the researchers were not in control of the data collection procedure. Missing data were common.

CONCLUSIONS

Data suggested most patients with PFD receiving outpatient physical therapy services were female, younger than 65 years, and had disorders lasting for more than 90 days. Combinations of urinary, bowel, or pelvic-floor pain disorders were not uncommon.

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.

Computerized adaptive testing--ready for ambulatory monitoring?

BACKGROUND

Computerized adaptive tests (CATs) have abundant theoretical advantages over established static instruments, which could improve ambulatory monitoring of patient-reported outcomes (PROs). However, an empirical demonstration of their practical benefits is warranted.

METHODS

We reviewed the literature and evaluated existing data to discuss the potential of CATs for use in ambulatory monitoring outside clinical facilities.

RESULTS

Computerized adaptive tests are not being used for ambulatory monitoring, but initial results from their use in health care research allow for discussion of some issues relevant to ambulatory care. Evidence shows that CATs can capture the most relevant health outcomes as well as established static tools, with substantially decreased respondent burden. They can be more precise than static tools of similar length and can reduce floor and ceiling effects. Computerized adaptive tests can reliably measure a construct over time with different items, which yields the potential of introducing item exposure control in ambulatory monitoring. Studies have shown that CATs can be at least as valid as well-designed static tools in group comparisons, but further investigation is needed to determine whether psychometric advantages lead to increased responsiveness of CATs.

CONCLUSIONS

Ambulatory monitoring of PROs demands short, yet very precise measurements, which can be repeated up to many times a day. Computerized adaptive tests may address several present shortcomings in ambulatory monitoring of PROs efficiently. However, most CAT developments have primarily focused on psychometric improvements. To use the full potential of CATs for ambulatory monitoring purposes, content must also be carefully considered.

Using intake and change in multiple psychosocial measures to predict functional status outcomes in people with lumbar spine syndromes: a preliminary analysis

BACKGROUND

Managing patients with lumbar spine syndromes who are seeking outpatient physical therapy represents a complex problem where psychosocial constructs such as fear-avoidance beliefs regarding physical activities or work activities, somatization, and depressive symptoms may affect functional status (FS) outcomes.

OBJECTIVE

The purpose of this study was to determine whether intake or changes in fear-avoidance beliefs regarding physical or work activities, somatization, and depressive symptoms assessed simultaneously affect FS outcomes prediction.

DESIGN

This study was a secondary analysis of prospectively collected, longitudinal, observational cohort data.

METHODS

Data analyzed were from adult patients (n=323) with lumbar syndromes classified as elevated versus not elevated on single-item screening instruments for fear-avoidance beliefs regarding physical or work activities, somatization, and depressive symptoms at intake and discharge. Prediction of minimal clinically important difference in FS was assessed separately for intake and change from intake to discharge classifications using logistic regression models controlling for important variables.

RESULTS

Intake and change models were strong (McFadden rho-squared values=.31 and .49, respectively). Patients classified as not elevated in fear-avoidance beliefs regarding physical activities but elevated in fear-avoidance beliefs regarding work activities, somatization, and depressive symptoms at intake were 5 out of 100 times less likely to report clinically important outcomes compared with being elevated in each measure. Patients not elevated in fear-avoidance beliefs regarding work activities and somatization at intake and discharge were 8 to 14 times more likely to report clinically important outcomes compared with being elevated in each measure.

LIMITATIONS

Sample size was limited. Data analyses were retrospective with no control of missing data.

CONCLUSIONS

Combinations of multiple psychosocial constructs were important predictors of FS outcomes and may assist patient management by: (1) identifying patients with elevated psychosocial constructs at intake and (2) tracking change in psychosocial variables for improved outcomes prediction. This model may prove helpful for future clinical and research applications to determine optimal psychosocial screening methods.

Total number and severity of comorbidities do not differ based on anatomical region of musculoskeletal pain

STUDY DESIGN

Secondary analysis, cross-sectional study.

OBJECTIVES

To (1) compare differences in individual comorbidity rates among patients with cervical, lumbar, and extremity pain complaints and (2) compare rates based on total number and severity in these same patient groups.

BACKGROUND

Comorbidities can impact recovery, prognosis, and potentially hinder participation in rehabilitation. Few studies have compared comorbidity rates among patients with different anatomical region of pain, to determine whether specific screening is warranted in physical therapy settings.

METHODS

Included in the analyses were 2375 patients who reported complete demographic, clinical, and comorbidity information using Patient Inquiry software. Comorbidity data were collected from the Functional Comorbidity Index (18 items) and 6 additional comorbidities, to assess the presence of medical disease across multiple body systems. Comorbidities were further classified as "nonsevere" or "severe," based on inclusion in the Charlson Comorbidity Index. Chi-square analyses investigated differences in the rates of total number and severe comorbidities. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated on rates with statistically significant differences (P<.001), using the lumbar spine as the reference group.

RESULTS

Of the 24 comorbid conditions included in this analysis, 3 nonsevere medical conditions (degenerative disc disease, obesity, and headache) had different rates among anatomical region. A lower rate for degenerative disc disease was associated with the extremity conditions (χ2 = 66.3; OR = 0.40; 95% CI: 0.32, 0.50). Higher rate of headache (χ2 = 115.3; OR = 3.01; 95% CI: 2.45, 3.70) and lower rate of obesity (χ2 = 16.2; OR = 0.64; 95% CI: 0.51, 0.80) were associated with cervical conditions. There were no differences among the 3 anatomical regions for total number or severe comorbidities.

CONCLUSION

Focused screening for degenerative disc disease, obesity, and headache may be warranted. However, the same strategy was not supported for total number or severe comorbidities, at least when considering comparative rates from this cohort. Physical therapists should consider the potential influence of total number and severe comorbidities equally for all anatomical regions of musculoskeletal pain.

LEVEL OF EVIDENCE

Differential diagnosis/symptom prevalence, level 3b.

Baseline dependency of minimal clinically important improvement

BACKGROUND

Minimal clinically important improvement (MCII) is the smallest outcome measure change important to patients. Research suggests that MCII is dependent on patients' baseline functional status measures.

OBJECTIVE

The purposes of this study were: (1) to confirm whether MCII is dependent on patients' admission scores and (2) to test whether MCII is dependent on selected demographic characteristics.

STUDY DESIGN AND SETTING

This was a prospective, longitudinal, observational cohort study of 6,651 patients with orthopedic knee impairments treated in 332 outpatient rehabilitation clinics in 27 states in the United States.

OUTCOME MEASURES

Patient self-reports of functional status (FS) from the Lower Extremity Functional Scale were assessed using a computerized adaptive testing application (0-100 scale).

METHODS

An anchored-based longitudinal method, with a 15-point Likert-type scale (-7 to +7), was used to provide a global rating of change (GROC). The MCII threshold for the GROC was defined at a cut-score of +3 or greater and was determined using nonparametric receiver operating characteristic curve analysis for each of the following variables: sex, symptom acuity, age group, and quartile of baseline FS scores.

RESULTS

The results showed that MCII was dependent on patient baseline and demographic characteristics. Patients who were male, were younger, had more-acute symptoms, or had lower FS scores at admission required more FS change to report meaningful change.

LIMITATIONS

As this study was a secondary analysis, how the length of treatment mediated the relationship between the independent and dependent variables was unclear.

CONCLUSIONS

Although a single MCII index may provide a standard cut-score defining the smallest FS change that is meaningful to patients, researchers and clinicians should be aware that MCII is context specific and not a fixed attribute. Current results may help researchers, clinicians, and policy makers to interpret FS change related to the importance of the change to the patient.

Effect of fear-avoidance beliefs of physical activities on a model that predicts risk-adjusted functional status outcomes in patients treated for a lumbar spine dysfunction

STUDY DESIGN

Retrospective analysis of a prospective, longitudinal cohort study of 30 858 patients being treated for a lumbar spine dysfunction in outpatient physical therapy.

OBJECTIVES

To determine effect of adding a single-item screening variable classifying patients with elevated versus not-elevated scores of fear-avoidance beliefs of physical activities at intake, on a model predicting risk-adjusted functional status (FS) outcomes.

BACKGROUND

Outcomes must be risk-adjusted before making meaningful interpretations. Elevated fear-avoidance beliefs scores have been predictive of poor outcomes. But the importance of elevated fear-avoidance scores in a multivariable model predicting FS outcomes needs further study.

METHODS

Using retrospective analyses, predictive ability (R2) of multivariable linear regression models of discharge FS with and without classification by elevated versus not-elevated fear-avoidance scores were compared, while controlling for intake FS, age, symptom acuity, surgical history, gender, number of comorbidities, and payer. Percent variance controlled and beta coefficients (95% confidence intervals) of each variable in both models were compared. A split-half design was used for model cross-validation. Predictive ratios (predicted FS, divided by actual discharge FS) were assessed.

RESULTS

Adding fear-avoidance beliefs classification to the discharge FS model improved (P<.001) model predictive ability but only slightly (R2 without, and with, fear-avoidance classification, 0.2997 and 0.3010, respectively). Variables impacted models similarly (95% confidence intervals not different). Fear-avoidance classification added 0.2% data variance control to the existing model. Cross-validation was supported. Predictive ratios were 1.09 and 1.10, without and with fear-avoidance, respectively.

CONCLUSION

Although screening for elevated fear-avoidance beliefs of physical activities significantly improves the FS outcomes predictive model, the amount of additional meaningful interpretation of FS outcomes was minimal. Exploration of other clinically relevant variables designed to improve outcomes prediction is warranted.

LEVEL OF EVIDENCE

Prognosis, level 2c.

Depressive symptoms, anatomical region, and clinical outcomes for patients seeking outpatient physical therapy for musculoskeletal pain

BACKGROUND

Clinical guidelines advocate the routine identification of depressive symptoms for patients with pain in the lumbar or cervical spine, but not for other anatomical regions.

OBJECTIVE

The purpose of this study was to investigate the prevalence and impact of depressive symptoms for patients with musculoskeletal pain across different anatomical regions. Design This was a prospective, associational study.

METHODS

Demographic, clinical, depressive symptom (Symptom Checklist 90-Revised), and outcome data were collected by self-report from a convenience sample of 8,304 patients. Frequency of severe depressive symptoms was assessed by chi-square analysis for demographic and clinical variables. An analysis of variance examined the influence of depressive symptoms and anatomical region on intake pain intensity and functional status. Separate hierarchical multiple regression models by anatomical region examined the influence of depressive symptoms on clinical outcomes.

RESULTS

Prevalence of severe depression was higher in women, in industrial and pain clinics, and in patients who reported chronic pain or prior surgery. Lower prevalence rates were found in patients older than 65 years and those who had upper- or lower-extremity pain. Depressive symptoms had a moderate to large effect on pain ratings (Cohen d=0.55-0.87) and a small to large effect on functional status (Cohen d=0.28-0.95). In multivariate analysis, depressive symptoms contributed additional variance to pain intensity and functional status for all anatomical locations, except for discharge values for the cervical region.

CONCLUSIONS

Rates of depressive symptoms varied slightly based on anatomical region of musculoskeletal pain. Depressive symptoms had a consistent detrimental influence on outcomes, except on discharge scores for the cervical anatomical region. Expanding screening recommendations for depressive symptoms to include more anatomical regions may be indicated in physical therapy settings.

Translating shoulder computerized adaptive testing generated outcome measures into clinical practice

STUDY DESIGN

Prospective longitudinal cohort study.

INTRODUCTION

Increased use of computerized adaptive tests (CATs) to generate outcome measures during rehabilitation has stimulated questions concerning score interpretation.

PURPOSE OF THE STUDY

The purpose of the study was to describe meaningful interpretations of scores from patient self-report shoulder functional status (FS) outcome measures estimated using a shoulder CAT (score range=0-100).

METHODS

We applied four approaches to the clinical interpretation of outcomes data from 30,987 patients with shoulder impairments receiving outpatient rehabilitation in 518 clinics in 30 states (United States) between August 2007 and July 2009. First, we used standard error of estimates to construct 95% confidence intervals for each CAT estimated score. Second, we estimated the percentile rank (PR) of FS scores. Third, we used two threshold approaches to define individual patient-level change: statistically reliable change (i.e., minimal detectable change or MDC) and clinically important change. Fourth, we developed and applied a functional staging model, the Shoulder Function Classification System (SFCS).

RESULTS

Precision of a single score was estimated by FS score ±4. Based on score distribution, 25th, 50th, and 75th PRs corresponded to intake FS scores of 43, 52, and 59 and discharge FS scores of 59, 68, and 80, respectively. MDC calculations indicated that changes in FS scores of 11 or more units represented statistically reliable change. FS score increments of eight or more units were estimated to represent minimal clinically important improvement based on receiver operating characteristic. The five-level SFCS was judged to be clinically logical and provide insight for clinical interpretation of patient progress.

CONCLUSIONS

Results may improve clinical interpretation of CAT-generated outcome measures and assist clinicians using patient-reported outcomes during clinical practice.

LEVEL OF EVIDENCE

Therapy level 2c.

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.

Clinical interpretation of outcome measures generated from a lumbar computerized adaptive test

BACKGROUND

A computerized adaptive test (CAT) provides a way of efficiently estimating functional status in people with specific impairments.

OBJECTIVE

The purpose of this study was to describe meaningful interpretations of functional status (FS) estimated using a lumbar CAT developed using items from the Back Pain Functional Scale (BPFS) and selected physical functioning items. Design and Setting This was a prospective longitudinal cohort study of 17,439 patients with lumbar spine impairments in 377 outpatient rehabilitation clinics in 30 states. Outcome Measures Patient self-reports of functional status were assessed using a lumbar CAT (0-100 scale).

METHODS

Outcome data were interpreted using 4 methods. First, the standard error of the estimate was used to construct a 95% confidence interval for each CAT estimated score. Second, percentile ranks of FS scores were presented. Third, 2 threshold approaches were used to define individual patient-level change: minimal detectable change (MDC) and clinically important change. Fourth, a functional staging model, the Back Pain Function Classification System (BPFCS), was developed and applied.

RESULTS

On average, precision of a single score was estimated by FS score+/-4. Based on score distribution, 25th, 50th and 75th percentile ranks corresponded to intake FS scores of 44, 51, and 59, and discharge FS scores of 54, 62, and 74, respectively. An MDC(95) value of 8 or more represented statistically reliable change. Receiver operating characteristic analyses supported that changes in FS scores of 5 or more represented minimal clinically important improvement. The BPFCS appeared clinically logical and provided insight for clinical interpretation of patient progress.

LIMITATIONS

The BPFCS should be assessed for validity using prospective designs.

CONCLUSIONS

Results may improve clinical interpretation of CAT-generated outcome measures and assist clinicians using patient-reported outcomes during physical therapist practice.

Weighted index explained more variance in physical function than an additively scored functional comorbidity scale

OBJECTIVE

1) examine association between the Functional Comorbidity Index (FCI) and discharge functional status (FS); 2) examine impact of FCI on FS when added to comprehensive models; and 3) compare additive FCI with weighted FCI and list of condition variables (list).

STUDY DESIGN AND SETTING

Patients were drawn from Focus On Therapeutic Outcomes, Inc. (FOTO) database (1/1/06-12/31/07). FS collected using computer adaptive tests. Linear regression examined association between FCI and FS. Three methods of including functional comorbidities (FC) were compared.

RESULTS

Relationship between FCI and FS varied by group (range, 0.02-0.9). Models with weighted index or list had similar R². Weighted FCI or list increased R² of crude models by <0.01 for cervical, shoulder, and lumbar; by 0.01 for wrist/hand, knee, and foot/ankle; by 0.02 for hip; by 0.03 for elbow; and by 0.08 for neurological. Addition of FCI to comprehensive models added <0.01 to R² (all groups). Weighted FCI increased R² by <0.01 for cervical, lumbar, and shoulder; by 0.01 for wrist/hand, hip, knee, and foot/ankle; by 0.02 for elbow; and by 0.04 for neurological; whereas list increased R² by <0.01 for cervical, shoulder, and lumbar; by 0.01 for knee and foot/ankle; by 0.02 for elbow, wrist/hand, and hip; and by 0.05 for neurological.

CONCLUSION

List of comorbidities or weighted FCI is preferable to using additive FCI.

A computerized adaptive test for patients with shoulder impairments produced responsive measures of function

BACKGROUND

Computerized adaptive tests (CATs) promise efficient outcomes data collection with little loss of measurement precision. The shoulder CAT has not been assessed for administrative efficiency, nor have prospective studies been completed to evaluate the sensitivity to change or the responsiveness of CAT-based functional status (CAT-FS) measures.

OBJECTIVE

The purpose of this study was to evaluate the efficiency and responsiveness of the shoulder CAT.

DESIGN

This was a secondary analysis of prospectively collected data.

METHODS

Data were analyzed from patients with shoulder impairments who received outpatient rehabilitation in 518 clinics in 30 US states. Over the testing time, 30,987 patients completed the shoulder CAT at intake, and of these, 13,805 completed the CAT at discharge (45% completion rate). The efficiency of routine CAT administration was evaluated, and the sensitivity to change and responsiveness of CAT-FS measures were assessed.

RESULTS

On average, patients took about 1.5 minutes (SD <2 minutes) to answer 6 CAT items (SD=2), which produced precise estimates of CAT-FS measures that adequately covered the content range and had negligible floor and minimal ceiling effects. Ninety-four percent of the patients had CAT-FS scores between 20 and 80, where upper-level 95% confidence interval (CI) standard errors were between 3.2 and 4.6 (out of 100). Of patients with both intake and discharge data, 79% had CAT-FS change scores greater than minimal detectable change, and 76% had changes greater than minimal clinically important improvement.

LIMITATIONS

Because this study was a secondary analysis, the results may have been affected by patient selection bias. Future studies would benefit from more complete data.

CONCLUSIONS

The results indicate the shoulder CAT was efficient and support the precision, sensitivity, and responsiveness of CAT-FS measures.

Clinical interpretation of computerized adaptive test outcome measures in patients with foot/ankle impairments

STUDY DESIGN

Prospective cohort study of 10 287 patients with foot/ankle impairments receiving outpatient physical therapy.

OBJECTIVES

To describe meaningful interpretations of functional status (FS) outcomes measures, estimated using a body-part-specific computerized adaptive test (CAT).

BACKGROUND

Increased use of CATs to generate outcome measures in rehabilitation has stimulated questions concerning score interpretation. Identifying meaningful intra-individual change and reporting clinical interpretation of those generated outcomes are essential to advance the quality of rehabilitation practice.

METHODS

We performed 4 approaches to clinically interpret outcomes data. First, we used the standard error of the estimate to construct a 90% confidence interval for each CAT estimated score. Second, we presented the percentile rank of FS scores. Third, we used 2 threshold approaches to define individual-patient-level change: statistically reliable change and clinically important change. Last, we illustrated a functional staging method.

RESULTS

Precision of a single score was estimated by an FS score of +/-4. Based on score distribution, percentile ranks at 25th, 50th, and 75th percentiles corresponded to intake FS scores of 38, 47, and 57, and discharge FS scores of 52, 64, and 77, respectively. Minimal detectable change supported 7 or more FS change units out of 100 represented statistically reliable change, and ROC analyses supported 8 or more FS change units represented minimal clinically important improvement. Using a functional staging system, we established 5 hierarchical functional status levels.

CONCLUSION

CAT-generated outcome measures can be interpreted to improve clinical interpretation and to assist clinicians in using patient-reported outcomes during therapy practice.

Associations between treatment processes, patient characteristics, and outcomes in outpatient physical therapy practice

OBJECTIVE

To identify how treatment processes are related to functional outcomes for patients seeking treatment for musculoskeletal impairments while controlling for demographic and health characteristics at intake.

DESIGN

Prospective, observational cohort study. Treatment processes were not altered. Data were collected continuously from June 2005 to January 2008. Descriptive statistics were applied to compare patient characteristics, interventions, and outcomes between impairment categories. Ordinary least-squares multiple regressions were used to examine associations between patient characteristics at intake, treatment processes, and functional outcomes.

SETTING

Fifty-four community-based outpatient physical therapy clinics of Maccabi Healthcare Services, a public health plan in Israel.

PARTICIPANTS

A consecutive sample of 22,019 adult patients (mean age 51.2 y, standard deviation=15.7, range 18-96, 58% women) seeking treatment due to lumbar spine, knee, cervical spine, or shoulder impairments with functional measurements at intake and discharge.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Functional status at discharge.

RESULTS

Explanatory power ranged from 30% to 39%. Better outcomes were associated with patient compliance with self-exercise and therapy attendance, application of therapeutic exercise and manual therapy, and completion of 3 or more functional surveys during the episode of care. Worse outcomes were associated with women, electrotherapy for pain management, and therapeutic ultrasound for shoulder impairments. Mixed results were found for group exercise programs.

CONCLUSIONS

The study of associations between treatment processes, patient characteristics, and outcomes helps to describe practice and can be used to suggest ways to improve outcomes in outpatient physical therapy practice.

Clinical interpretation of a lower-extremity functional scale-derived computerized adaptive test

BACKGROUND

The increasing use of computerized adaptive tests (CATs) to generate outcome measures during rehabilitation has prompted questions concerning score interpretation.

OBJECTIVE

The purpose of this study was to describe meaningful interpretations of functional status (FS) outcome measures estimated with a body part-specific CAT developed from the Lower-Extremity Functional Scale (LEFS).

DESIGN

This investigation was a prospective cohort study of 8,714 people who had hip impairments and were receiving physical therapy in 257 outpatient clinics in 31 states (United States) between January 2005 and June 2007.

METHODS

Four approaches were used to clinically interpret outcome data. First, the standard error of the estimate was used to construct the 90% confidence interval for each CAT-generated score estimate. Second, percentile ranks were applied to FS scores. Third, 2 threshold approaches were used to define individual subject-level change: statistically reliable change and clinically important change. The fourth approach was a functional staging method.

RESULTS

The precision of a single score was estimated from the FS score +/-4. On the basis of the score distribution, 25th, 50th, and 75th percentile ranks corresponded to intake FS scores of 40, 48, and 59 and discharge FS scores of 50, 61, and 75, respectively. The reliable change index supported the conclusion that changes in FS scores of 7 or more units represented statistically reliable change, and receiver operating characteristic analyses supported the conclusion that changes in FS scores of 6 or more units represented minimal clinically important improvement. Participants were classified into 5 hierarchical levels of FS using a functional staging method.

LIMITATIONS

Because this study was a secondary analysis of prospectively collected data via a proprietary database management company, generalizability of results may be limited to participating clinics.

CONCLUSIONS

The results demonstrated how outcome measures generated from the hip LEFS CAT can be interpreted to improve clinical meaning. This finding might facilitate the use of patient-reported outcomes by clinicians during rehabilitation services.

Screening for elevated levels of fear-avoidance beliefs regarding work or physical activities in people receiving outpatient therapy

BACKGROUND

Screening people for elevated levels of fear-avoidance beliefs is uncommon, but elevated levels of fear could worsen outcomes. Developing short screening tools might reduce the data collection burden and facilitate screening, which could prompt further testing or management strategy modifications to improve outcomes.

OBJECTIVE

The purpose of this study was to develop efficient yet accurate screening methods for identifying elevated levels of fear-avoidance beliefs regarding work or physical activities in people receiving outpatient rehabilitation.

DESIGN

A secondary analysis of data collected prospectively from people with a variety of common neuromusculoskeletal diagnoses was conducted.

METHODS

Intake Fear-Avoidance Beliefs Questionnaire (FABQ) data were collected from 17,804 people who had common neuromusculoskeletal conditions and were receiving outpatient rehabilitation in 121 clinics in 26 states (in the United States). Item response theory (IRT) methods were used to analyze the FABQ data, with particular emphasis on differential item functioning among clinically logical groups of subjects, and to identify screening items. The accuracy of screening items for identifying subjects with elevated levels of fear was assessed with receiver operating characteristic analyses.

RESULTS

Three items for fear of physical activities and 10 items for fear of work activities represented unidimensional scales with adequate IRT model fit. Differential item functioning was negligible for variables known to affect functional status outcomes: sex, age, symptom acuity, surgical history, pain intensity, condition severity, and impairment. Items that provided maximum information at the median for the FABQ scales were selected as screening items to dichotomize subjects by high versus low levels of fear. The accuracy of the screening items was supported for both scales.

LIMITATIONS

This study represents a retrospective analysis, which should be replicated using prospective designs. Future prospective studies should assess the reliability and validity of using one FABQ item to screen people for high levels of fear-avoidance beliefs.

CONCLUSIONS

The lack of differential item functioning in the FABQ scales in the sample tested in this study suggested that FABQ screening could be useful in routine clinical practice and allowed the development of single-item screening for fear-avoidance beliefs that accurately identified subjects with elevated levels of fear. Because screening was accurate and efficient, single IRT-based FABQ screening items are recommended to facilitate improved evaluation and care of heterogeneous populations of people receiving outpatient rehabilitation.

Computerized adaptive test for patients with foot or ankle impairments produced valid and responsive measures of function

OBJECTIVE

We tested the item response theory (IRT) model assumptions of the original item bank, and evaluated the practical and psychometric adequacy, of a computerized adaptive test (CAT) for patients with foot or ankle impairments seeking rehabilitation in outpatient therapy clinics.

METHODS

Data from 10,287 patients with foot or ankle impairments receiving outpatient physical therapy were analyzed. We first examined the unidimensionality, fit, and invariance IRT assumptions of the CAT item bank. Then we evaluated the efficiency of the CAT administration and construct validity and sensitivity of change of the foot/ankle CAT measure of lower-extremity functional status (FS).

RESULTS

Results supported unidimensionality, model fit, and invariance of item parameters and patient ability estimates. On average, the CAT used seven items to produce 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 prior to receiving rehabilitation reported worse discharge FS. Seventy-one percent of patients obtained statistically significant change at follow-up. Change of 8 FS units (scale 0-100) represented minimal clinically important improvement.

CONCLUSIONS

We concluded that the foot/ankle item bank met IRT assumptions and that the CAT FS measure was precise, valid, and responsive, supporting its use in routine clinical application.