Country-specific reference values for PROMIS® pain, physical function and participation measures compared to US reference values

INTRODUCTION

Patient-Reported Outcomes Measurement Information System (PROMIS^®) is commonly used across medical conditions. To facilitate interpretation of scores across countries, we calculated Dutch reference values for PROMIS Physical Function (PROMIS-PF), Pain Interference (PROMIS-PI), Pain Behavior (PROMIS-PB), Ability to Participate in Social Roles and Activities (PROMIS-APSRA), and Satisfaction with Social Roles and Activities (PROMIS-SSRA), as compared to US reference values.

PATIENTS AND METHODS

A panel completed full PROMIS-PF (n=1310), PROMIS-PI and PROMIS-PB (n=1052), and PROMIS-APSRA and PROMIS-SSRA (n=1002) item banks and reported their level of health per domain (no, mild, moderate, severe limitations). T-scores were calculated by sample and subgroups (age, gender, self-reported level of domain). Distribution-based and anchor-based thresholds for mild, moderate, and severe scores were determined.

RESULTS

Mean T-scores were close to the US mean of 50 for PROMIS-PF (49.8) and PROMIS-APSRA (50.6), lower for PROMIS-SSRA (47.5) and higher for PROMIS-PI (54.9) and PROMIS-PB (52.0). Distribution-based thresholds for mild, moderate, and severe scores were comparable to US recommended cut-off values (except for PROMIS-PI) but participants reported limitations 'earlier' than suggested thresholds.

CONCLUSION

Dutch reference values were close to US reference values for some PROMIS domains but not all. We recommend country-specific reference values to facilitate worldwide PROMIS use.KEY MESSAGESPROMIS offers universally applicable IRT-based efficient and patient-friendly measures to assess commonly relevant patient-reported outcomes across medical conditions.To support the use of PROMIS in daily clinical practice and research across the world, country-specific general population reference values should be obtained.More research is necessary to obtain reliable and valid cut-off values for what constitutes mild, moderate and severe scores from the patients' perspective.

A multidisciplinary lifestyle program for metabolic syndrome-associated osteoarthritis: the "Plants for Joints" randomized controlled trial

OBJECTIVE

To determine the effectiveness of the "Plants for Joints" multidisciplinary lifestyle program in patients with metabolic syndrome-associated osteoarthritis (MSOA).

DESIGN

Patients with hip or knee MSOA were randomized to the intervention or control group. The intervention group followed a 16-week program in addition to usual care based on a whole food plant-based diet, physical activity, and stress management. The control group received usual care. The patient-reported Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC) total score (range 0-96) was the primary outcome. Secondary outcomes included other patient-reported, anthropometric, and metabolic measures. An intention-to-treat analysis with a linear-mixed model adjusted for baseline values was used to analyze between-group differences.

RESULTS

Of the 66 people randomized, 64 completed the study. Participants (84% female) had a mean (SD) age of 63 (6) years and body mass index of 33 (5) kg/m2. After 16 weeks, the intervention group (n = 32) had a mean 11-point larger improvement in WOMAC-score (95% CI 6-16; p = 0.0001) compared to the control group. The intervention group also lost more weight (-5 kg), fat mass (-4 kg), and waist circumference (-6 cm) compared to the control group. Patient-Reported Outcomes Measurement Information System (PROMIS) fatigue, pain interference, C-reactive protein, hemoglobin A1c, fasting glucose, and low-density lipoproteins improved in the intervention versus the control group, while other PROMIS measures, blood pressure, high-density lipoproteins, and triglycerides did not differ significantly between the groups.

CONCLUSION

The "Plants for Joints" lifestyle program reduced stiffness, relieved pain, and improved physical function in people with hip or knee MSOA compared to usual care.

Suitability of the animated activity questionnaire for use as computer adaptive test: establishing the AAQ-CAT

PURPOSE

The animated activity questionnaire (AAQ) is a computer-based measure of activity limitations. To answer a question, patients choose the animation of a person performing an activity that matches their own level of limitation. The AAQ has not yet been tested for suitability to be applied as computer-adaptive test (CAT). Thus, the objective of this study was to develop and evaluate an AAQ-based CAT to facilitate the application of the AAQ in daily clinical care.

METHODS

Patients (n = 1408) with hip/knee osteoarthritis from Brazil, Denmark, France, The Netherlands, Norway, Spain, and the UK responded to all 17 AAQ items. Assumptions of item-response theory (IRT) modelling were investigated. To establish item parameters for the CAT, a graded response model was estimated. To evaluate the performance of post-hoc simulated AAQ-based CATs, precision, test length, and construct validity (correlations with well-established measures of activity limitations) were evaluated.

RESULTS

Unidimensionality (CFI = 0.95), measurement invariance (R²-change < 2%), and IRT item fit (S-X² p > .003) of the AAQ were supported. Performing simulated CATs, the mean test length was more than halved (≤ 8 items), while the range of precise measurement (standard error ≤ 0.3) was comparable to the full AAQ. The correlations between original AAQ scores and three AAQ-CAT versions were ≥ 0.95. Correlations of AAQ-CAT scores with patient-reported and performance measures of activity limitations were ≥ 0.60.

CONCLUSION

The almost non-verbal AAQ-CAT is an innovative and efficient tool in patients with hip/knee osteoarthritis from various countries, measuring activity limitations with lower respondent burden, but similar precision and construct validity compared to the full AAQ.

Psychometric properties and reference values of the Patient-Reported Outcomes Measurement Information System (PROMIS) sleep item banks in the Dutch general population

Psychometric properties of the v1.0 Patient-Reported Outcomes Measurement Information System (PROMIS®) sleep disturbance (27 items) and sleep-related impairment (SRI; 16 items) item banks, short forms derived from the item bank, and simulated computerised adaptive test (CAT), were assessed in a representative sample of 1,006 adults from the Dutch general population. For sleep disturbance all items fitted the item response theory model. Four items showed differential item functioning (i.e., lack of measurement invariance) for age and two for language but the impact on scores (expressed as T-scores) was small. Reliable scores (r > 0.90) were found for 92.2%-96.3% of respondents with the full bank, short forms with six and eight items, and CAT, but for only 25.6% with the four-item short form. For SRI two items did not fit the item response theory model. Four items showed differential item functioning for language but the impact on T-scores was small. Reliable scores were found for 82.1% with the full bank, for 47.8%-69.5% with short forms and CAT. T-scores of 49.7 and 49.3 represent the average score of the Dutch general population for sleep disturbance and SRI, respectively. In conclusion, sufficient structural validity, reliability, and cross-cultural validity was found for the full banks but short forms of four items are not reliable enough for clinical practice. For SRI we recommend the full item bank if this is the primary outcome.

Smartphone-Assisted Patient-Initiated Care Versus Usual Care in Patients With Rheumatoid Arthritis and Low Disease Activity: A Randomized Controlled Trial

OBJECTIVE

We developed a smartphone application for patients with rheumatoid arthritis (RA) that allows them to self-monitor their disease activity in between clinic visits by answering a weekly Routine Assessment of Patient Index Data 3. This study was undertaken to assess the safety (noninferiority in the Disease Activity Score in 28 joints using the erythrocyte sedimentation rate [DAS28-ESR]) and efficacy (reduction in number of visits) of patient-initiated care assisted using a smartphone app, compared to usual care.

METHODS

A 12-month, randomized, noninferiority clinical trial was conducted in RA patients with low disease activity and without treatment changes in the past 6 months. Patients were randomized 1:1 to either app-supported patient-initiated care with a scheduled follow-up consultation after a year (app intervention group) or usual care. The coprimary outcome measures were noninferiority in terms of change in DAS28-ESR score after 12 months and the ratio of the mean number of consultations with rheumatologists between the groups. The noninferiority limit was 0.5 difference in DAS28-ESR between the groups.

RESULTS

Of the 103 randomized patients, 102 completed the study. After a year, noninferiority in terms of the DAS28-ESR score was established, as the 95% confidence interval (95% CI) of the mean ΔDAS28-ESR between the groups was within the noninferiority limit: -0.04 in favor of the app intervention group (95% CI -0.39, 0.30). The number of rheumatologist consultations was significantly lower in the app intervention group compared to the usual care group (mean ± SD 1.7 ± 1.8 versus 2.8 ± 1.4; visit ratio 0.62 [95% CI 0.47, 0.81]).

CONCLUSION

Patient-initiated care supported by smartphone self-monitoring was noninferior to usual care in terms of the ΔDAS28-ESR and led to a 38% reduction in rheumatologist consultations in RA patients with stable low disease activity.

Towards standardization of measuring anxiety and depression: Differential item functioning for language and Dutch reference values of PROMIS item banks

Introduction

The outcomes anxiety and depression are measured frequently by healthcare providers to assess the impact of a disease, but with numerous instruments. PROMIS item banks provide an opportunity for standardized measurement. Cross-cultural validity of measures and the availability of reference values are prerequisites for standardized measurement.

Methods

PROMIS Anxiety and Depression item banks were completed by 1002 representative Dutch persons. To evaluate cross-cultural validity, data from US participants in PROMIS wave 1 were used and differential item functioning (DIF) was investigated, using an iterative hybrid of logistic regression and item response theory. McFadden’s pseudo R²-change of 2% was the critical threshold. The impact of any DIF on full item banks and short forms was investigated. To obtain Dutch reference values, T-scores for anxiety and depression were calculated for the complete Dutch sample, and age-group and gender subpopulations. Thresholds corresponding to normal limits, mild, moderate and severe symptoms were computed.

Results

In both item banks, two items had DIF but with minimal impact on population level T-scores for full item banks and short forms. The Dutch general population had a T-score of 49.9 for anxiety and 49.6 for depression, similar to the T-scores of 50.0 of the US general population. T-scores for age-group and gender subpopulations were also similar to T-scores of the US general population. Thresholds for mild, moderate and severe anxiety and depression were set to 55, 60 and 70, identical to US thresholds.

Conclusions

The limited number of items with DIF and its minimal impact, enables the use of standard (US) item parameters and comparisons of scores between Dutch and US populations. The Dutch reference values provide an important tool for healthcare professionals and researchers to evaluate and interpret symptoms of anxiety and depression, stimulating the uptake of PROMIS measures, and contributing to standardized outcome measurement.

High-intensity versus low-intensity resistance training in patients with knee osteoarthritis: A randomized controlled trial

OBJECTIVES

To assess whether (i) high-intensity resistance training (RT) leads to increased muscle strength compared to low-intensity RT in patients with knee osteoarthritis (OA); and (ii) RT with vitamin D supplementation leads to increased muscle strength compared to placebo in a subgroup with vitamin D deficiency.

DESIGN

Randomized controlled trial.

SETTING

Outpatient rehabilitation centre.

SUBJECTS

Patients with knee OA.

INTERVENTIONS

12 weeks of RT at high-intensity RT (70-80% of 1-repetition maximum (1-RM)) or low-intensity RT (40-50% of 1-RM) and 24 weeks of vitamin D (1200 International units vitamin D3 per day) or placebo supplementation.

MAIN MEASURES

Primary outcome measure was isokinetic muscle strength. Other outcome measure for muscle strength was the estimated 1-RM. Secondary outcome measures were knee pain and physical functioning.

RESULTS

177 participants with a mean age of 67.6 ± 5.8 years were included, of whom 50 had vitamin D deficiency. Isokinetic muscle strength (in Newton metre per kilogram bodyweight) at start, end and 24 weeks after the RT was 0.98 ± 0.40, 1.11 ± 0.40, 1.09 ± 0.42 in the high-intensity group and 1.02 ± 0.41, 1.15 ± 0.42, 1.12 ± 0.40 in the low-intensity group, respectively. No differences were found between the groups, except for the estimated 1-RM in favour of the high-intensity group. In the subgroup with vitamin D deficiency, no difference on isokinetic muscle strength was found between the vitamin D and placebo group.

CONCLUSIONS

High-intensity RT did not result in greater improvements in isokinetic muscle strength, pain and physical functioning compared to low-intensity RT in knee OA, but was well tolerated. Therefore these results suggest that either intensity of resistance training could be utilised in exercise programmes for patients with knee osteoarthritis. No synergistic effect of vitamin D supplementation and RT was found, but this finding was based on underpowered data.

Association between measures of muscle strength and performance of daily activities in patients with knee osteoarthritis

Objectives

Most studies of knee osteoarthritis use isokinetic peak strength as a measure of muscle strength. However, estimated one-repetition maximum (1-RM) may have a stronger relationship than isokinetic peak strength with daily activities. The aim of this study was to test the following hypotheses: first, the estimated 1-RM is more strongly associated than isokinetic peak strength with daily activities; and secondly, the estimated 1-RM is most strongly associated with the 6-minute walk test (6MWT), followed by the Get Up and Go test (GUG test) and the stair-climb test.

Methods

Data were used for 177 patients with knee osteoarthritis from a randomized controlled trial on improving muscle strength. The patients had a mean age of 67.6 ± 5.8 years. Isokinetic peak strength was measured using a dynamometer, 1-RM was estimated with the 10-RM test, and physical performance was measured with the 6-minute walk test (6MWT), get-up and go test (GUG) test and stair-climb test, at the start and end of 12 weeks of resistance training. Linear regression analyses provided standardized betas (β) that were comparable between the different associations between measures of muscle strength and daily activities.

Results

Compared with the estimated 1-RM, isokinetic peak strength was more strongly associated with all performance-based measures. The associations between the estimated 1-RM and performance-based tests were not ranked in the order hypothesized (6MWT, GUG test, stair-climb test).

Conclusion

Contrary to the first hypothesis, isokinetic peak strength showed stronger associations with all daily activities than did estimated 1-RM. In addition, the second hypothesis regarding the activity-specific pattern for the 1-RM with regards walking, chair rising and stair climbing measurements was not confirmed.

Measurement properties of the Dutch PROMIS-29 v2.1 profile in people with and without chronic conditions

PURPOSE

To investigate the structural validity, internal consistency, measurement invariance, and construct validity of the Dutch PROMIS-29 v2.1 profile, including seven physical (e.g., pain, physical function), mental (e.g., depression, anxiety), and social (e.g., role functioning) domains of health, in a Dutch general population sample including subsamples with and without chronic diseases.

METHODS

The PROMIS-29 was completed by 63,602 participants from the Lifelines cohort study. Structural validity of the PROMIS-29, including unidimensionality of each domain and the physical and mental health summary scores, was evaluated using factor analyses (criteria: CFI ≥ 0.95, TLI ≥ 0.95, RMSEA ≤ 0.06, SRMR ≤ 0.08). Internal consistency, measurement invariance (no differential item functioning (DIF) for age, gender, administration mode, educational level, ethnicity, chronic diseases), and construct validity (hypotheses on known-groups validity and correlations between domains) were assessed per domain.

RESULTS

The factor structure of the seven domains was supported (CFI = 0.994, TLI = 0.993, RMSEA = 0.046, SRMR = 0.031) as was unidimensionality of each domain, both in the entire sample and the subsamples. Model fit of the physical and mental health summary scores reached the criteria, and scoring coefficients were obtained. Cronbach's alpha for the seven PROMIS-29 domains ranged from 0.75 to 0.96 in the complete sample. No DIF was detected. Of the predefined hypotheses, 78% could be confirmed.

CONCLUSION

Sufficient structural validity, internal consistency and measurement invariance were found, both in the entire sample and in subsamples with and without chronic diseases. Requirements for sufficient evidence for construct validity were (almost) met for most subscales. Future studies should investigate test-retest reliability, measurement error, and responsiveness of the PROMIS-29.

Muscle weakness is associated with non-contractile muscle tissue of the vastus medialis muscle in knee osteoarthritis

BACKGROUND

Quadriceps weakness is assumed to be associated with compositional properties of the vastus medialis muscle in patients with knee osteoarthritis (OA).

METHODS

The aim was to determine the association of non-contractile muscle tissue in the vastus medialis muscle, measured with routine MRI, with muscle extensor strength in patients with knee OA. Sagittal T1-weighted 3T MRI of 94 patients with knee OA, routinely acquired in clinical practice were used for analysis. Using the MRI's, the amount of non-contractile muscle tissue in the vastus medialis muscle was measured, expressed as a percentage of (non)-contractile tissue, dichotomized into a low and a high non-contractile percentage group. Muscle strength was assessed by isokinetic measurement of knee extensors and by conduction of the Get-Up and Go (GUG) test. In regression analyses, associations of percentage of non-contractile muscle tissue with muscle strength and GUG time were determined and controlled for sex, age, BMI and radiographic severity.

RESULTS

A high percentage of non-contractile muscle tissue (> 11.2%) was associated with lower muscle strength (B = -0.25, P = 0.006) and with longer GUG time (B = 1.09, P = 0.021). These associations were specifically confounded by sex and BMI, because these two variables decreased the regression coefficient (B) with > 10%.

CONCLUSIONS

A high percentage of non-contractile muscle tissue in the vastus medialis muscle measured by clinical T1-weighted 3T MRI is associated with muscle weakness. The association is confounded by sex and BMI. Non-contractile muscle tissue seems to be an important compositional property of the vastus medialis muscle underlying quadriceps weakness.

Reducing the number of test items of the Action Research Arm Test post stroke: A decision tree analysis

Objective - The present study aimed to create a shorter version of the Action Research Arm Test (ARAT) without compromising its measurement properties. Design - Secondary analysis of stroke recovery cohorts that used the ARAT to measure upper-limb impairment. Setting - Rehabilitation centers. Participants - Patients with stroke from five different stroke recovery cohorts. Interventions - Not applicable. Main Outcome Measures - A decision tree version of the ARAT (ARAT-DT) was developed using Chi-squared Automated Interaction Detection (CHAID). In an independent validation subset, criterion validity, agreement of ARAT-DT with original ARAT scores and score categories, and construct validity with the Fugl-Meyer upper extremity (FM-UE) score were determined. Results - In total, 3738 ARAT measurements were available involving 1,425 subjects. CHAID analysis in the development subset (n=2803) revealed an optimized decision tree with a maximum of four consecutive items. In the validation dataset (n=935), the ARAT-DT differed by a mean of 0.19 points (0.3% of the total scale) from the original ARAT scores (limits of agreement: -5.67 to 6.05). The ARAT-DT demonstrated excellent criterion validity with the original ARAT scores (ICC=0.99 and ρ=0.99) and scoring categories (κ_w=0.97). The ARAT-DT showed very good construct validity with the FM-UE motor scale (ρ=0.92). Conclusion - A decision tree version of the ARAT was developed, reducing the maximum number of items necessary for ARAT administration from 19 to 4. The scores produced by the decision tree had excellent criterion validity with original ARAT scores.

Psychometric properties of the patient-reported outcomes measurement information system scale v1.2: global health (PROMIS-GH) in a Dutch general population

Purpose

To assess the psychometric properties of the Dutch-Flemish Patient-Reported Outcome Measurement Information System Scale v1.2 – Global Health (PROMIS-GH).

Methods

The PROMIS-GH (also referred to as PROMIS-10) was administered to 4370 persons from the Dutch general population. Unidimensionality (CFI ≥ 0.95; TLI ≥ 0.95; RMSEA ≤ 0.06; SRMR ≤ 0.08), local independence (residual correlations < 0.20), monotonicity (H > 0.30), model fit with the Graded Response Model (GRM, p < 0.001), internal consistency (alpha > 0.75), precision (total score information across the latent trait), measurement invariance (no Differential Item Functioning [DIF]), and cross-cultural validity (no DIF for language, Dutch vs. United States English) of its subscales, composed of four items each, Global Mental Health (GMH) and Global Physical Health (GPH), were assessed.

Results

Confirmatory factor analyses, on both subscales, revealed slight departures from unidimensionality for GMH (CFI = 0.98; TLI = 0.95, RMSEA = 0.22; SRMR = 0.04) and GPH (CFI = 0.99; TLI = 0.97; RMSEA = 0.12; SRMR = 0.03). Local independence, monotonicity, GRM model fit, internal consistency, precision and cross-cultural validity were supported. However, Global10 (emotional problems) showed misfit on the GMH subscale, while Global08 (fatigue) presented DIF for age.

Conclusion

The psychometric properties of the PROMIS-GH in the Dutch population were considered acceptable. Sufficient local independence, monotonicity, GRM fit, internal consistency, measurement invariance and cross-cultural validity were found. If future studies find similar results, structural validity of the GMH could be enhanced by improving or replacing Global10 (emotional problems).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12955-021-01855-0.

Common patient-reported outcomes across ICHOM Standard Sets: the potential contribution of PROMIS®

BACKGROUND

The International Consortium for Health Outcomes Measurement (ICHOM) develops condition-specific Standard Sets of outcomes to be measured in clinical practice for value-based healthcare evaluation. Standard Sets are developed by different working groups, which is inefficient and may lead to inconsistencies in selected PROs and PROMs. We aimed to identify common PROs across ICHOM Standard Sets and examined to what extend these PROs can be measured with a generic set of PROMs: the Patient-Reported Outcomes Measurement Information System (PROMIS®).

METHODS

We extracted all PROs and recommended PROMs from 39 ICHOM Standard Sets. Similar PROs were categorized into unique PRO concepts. We examined which of these PRO concepts can be measured with PROMIS.

RESULTS

A total of 307 PROs were identified in 39 ICHOM Standard Sets and 114 unique PROMs are recommended for measuring these PROs. The 307 PROs could be categorized into 22 unique PRO concepts. More than half (17/22) of these PRO concepts (covering about 75% of the PROs and 75% of the PROMs) can be measured with a PROMIS measure.

CONCLUSION

Considerable overlap was found in PROs across ICHOM Standard Sets, and large differences in terminology used and PROMs recommended, even for the same PROs. We recommend a more universal and standardized approach to the selection of PROs and PROMs. Such an approach, focusing on a set of core PROs for all patients, measured with a system like PROMIS, may provide more opportunities for patient-centered care and facilitate the uptake of Standard Sets in clinical practice.

Construct validity, responsiveness, and utility of change indicators of the Dutch-Flemish PROMIS item banks for depression and anxiety administered as computerized adaptive test (CAT): A comparison with the Brief Symptom Inventory (BSI)

We evaluated construct validity, responsiveness, and utility of change indicators of the Dutch-Flemish PROMIS adult v1.0 item banks for Depression and Anxiety administered as computerized adaptive test (CAT). Specifically, the CATs were compared to the Brief Symptom Inventory (BSI) using pre- and re-test data of adult patients treated for common mental disorders (N = 400; median pre-to-re-test interval = 215 days). Construct validity was evaluated with Pearson's correlations and Cohen's ds; responsiveness with Pearson's correlations and pre-post effect sizes (ES); utility of change indicators with kappa coefficients and percentages of (dis)agreement. The results showed that the PROMIS CATs measure similar constructs as matching BSI scales. Under the assumption of measuring similar constructs, the CAT and BSI Depression scales were similarly responsive. For the Anxiety scales, we found a higher responsiveness for CAT (ES = 0.64) compared to the BSI (ES = 0.50). Finally, both CATs categorized the change scores of more patients as changed compared to matching BSI scales, indicating that the PROMIS CATs may be more able to detect actual change than the BSI. Based on these findings, the PROMIS CATs may be considered a modest improvement over matching BSI scales as tools for reviewing treatment progress with patients. We discuss several additional differences between the PROMIS CATs and the BSI to help test users choose instruments. These differences include the adopted measurement theory (Item Response Theory vs. Classical Test Theory), the mode of administration (CAT vs. fixed items), and the area of application (universal vs. predominantly clinical). (PsycInfo Database Record (c) 2021 APA, all rights reserved).

From statistics to clinics: the visual feedback of PROMIS® CATs

Background

To reduce the burden of completing Patient-Reported Outcome Measures (PROMs), PROMIS® Computerized Adaptive Tests (CATs) are being implemented in pediatric clinical practice. We aimed to develop recommendations for visual feedback options for PROMIS CATs on individual item and domain score level as an evidence-based feedback recommendation for PROMIS CATs is lacking.

Methods

Focus groups were held with clinicians who use the KLIK PROM portal. Literature-based feedback options were provided to initiate group discussion. Data was analyzed using thematic coding method. Additionally, a questionnaire was sent out to assess patients’ (12-18y) and parents’ (child 0-18y) preference for individual item feedback. Data was analyzed using descriptive statistics.

Results

Six focus groups were held (N = 28 clinicians). Regarding individual item feedback, showing the complete item bank, with only responses to administered items in traffic light colors was preferred. For domain scores, line graphs were preferred, including numerical (T-)scores, reference and cut-off lines, and traffic light colors. Separate graphs per domain, ranked in order of importance and harmonization of directionality (‘higher = better’) were considered important. Questionnaire results (N = 31 patients/N = 131 parents) showed that viewing their own item responses was preferred above receiving no item feedback by 58.1% of the patients and 77.1% of the parents.

Conclusions

Based on the outcomes and after discussion with the Dutch-Flemish PROMIS National Center, recommendations for PROMIS CAT feedback options were developed. PROMIS CATs can now be used in clinical practice to help clinicians monitor patient outcomes, while reducing the burden of completing PROMs for patients significantly.

A Patient-Reported Outcomes Measurement Information System Short Form for Measuring Physical Function During Geriatric Rehabilitation: Test-Retest Reliability, Construct Validity, Responsiveness, and Interpretability

OBJECTIVES

To study the test-retest reliability and measurement error, construct validity, responsiveness, interpretability, and floor/ceiling effects of a Patient-Reported Outcomes Measurement Information System (PROMIS) short form designed to measure physical function in geriatric rehabilitation patients (PROMIS-PF-GR).

DESIGN

Prospective cohort.

SETTING AND PARTICIPANTS

Inpatient geriatric rehabilitation patients.

METHODS

We evaluated the test-retest reliability by re-administering PROMIS-PF-GR 3 to 5 days after the admission measurement. The intraclass correlation coefficient (ICC) was calculated to determine test-retest reliability; an ICC of ≥0.70 was considered sufficient. Measurement error was established by calculating the standard error of measurement and smallest detectable change. Construct validity and responsiveness were determined by testing a priori formulated hypotheses (criterion: ≥75% hypothesis not rejected). Interpretability was evaluated by calculating the minimal important change using predictive modeling and a global rating as criterion for change. Floor/ceiling effects were established by calculating the percentage patients with the minimum/maximum raw score (criterion: ≤15%) at admission and discharge.

RESULTS

A total of 207 patients participated in the study [mean ± standard deviation age (80 ± 8.3 years), 58% female]. More than one-half of patients (56%) reported to be improved during rehabilitation. The ICC was 0.79 (95% confidence interval 0.70-0.84), the standardized error of measurement was 3.8, and the smallest detectable change 10.6. None of the 4 hypotheses for construct validity were rejected; 2 out of 5 hypotheses for responsiveness were rejected. The minimal important change was 8.0 (95% confidence interval 4.1-12.5). No floor/ceiling effects were found.

CONCLUSIONS AND IMPLICATIONS

The PROMIS-PG-GR showed sufficient test-retest reliability, measurement error, and construct validity. We did not find sufficient evidence for responsiveness, which may be due to the unexplained weak correlation between the PROMIS change score and the Global Rating Scale. We still recommend the use the PROMIS-PG-GR for measuring self-reported physical function in geriatric rehabilitation.

International application of PROMIS computerized adaptive tests: US versus country-specific item parameters can be consequential for individual patient scores

OBJECTIVE

PROMIS offers computerized adaptive tests (CAT) of patient-reported outcomes, using a single set of US-based IRT item parameters across populations and language-versions. The use of country-specific item parameters has local appeal, but also disadvantages. We illustrate the effects of choosing US or country-specific item parameters on PROMIS CAT T-scores.

STUDY DESIGN AND SETTING

Simulations were performed on response data from Dutch chronic pain patients (n = 1110) who completed the PROMIS Pain Behavior item bank. We compared CAT T-scores obtained with (1) US parameters; (2) Dutch item parameters; (3) US item parameters for DIF-free items and Dutch item parameters (rescaled to the US metric) for DIF items; (4) Dutch item parameters for all items (rescaled to the US metric).

RESULTS

Without anchoring to a common metric, CAT T-scores cannot be compared. When scores were rescaled to the US metric, mean differences in CAT T-scores based on US vs. Dutch item parameters were negligible. However, 0.9%-4.3% of the T-score differences were larger than 5 points (0.5 SD).

CONCLUSION

The choice of item parameters can be consequential for individual patient scores. We recommend more studies of translated CATs to examine if strategies that allow for country-specific item parameters should be further investigated.

Psychometric Properties of the Pediatric Patient-Reported Outcomes Measurement Information System Item Banks in a Dutch Clinical Sample of Children With Juvenile Idiopathic Arthritis

Objective

To assess the psychometric properties of 8 pediatric Patient‐Reported Outcomes Measurement Information System (PROMIS) item banks in a clinical sample of children with juvenile idiopathic arthritis (JIA).

Methods

A total of 154 Dutch children (mean ± SD age 14.4 ± 3.0 years; range 8–18 years) with JIA completed 8 pediatric version 1.0 PROMIS item banks (anger, anxiety, depressive symptoms, fatigue, pain interference, peer relationships, physical function mobility, physical function upper extremity) twice and the Pediatric Quality of Life Inventory (PedsQL) and the Childhood Health Assessment Questionnaire (C‐HAQ) once. Structural validity of the item banks was assessed by fitting a graded response model (GRM) and inspecting GRM fit (comparative fit index [CFI], Tucker‐Lewis index [TLI], and root mean square error of approximation [RMSEA]) and item fit (S‐X² statistic). Convergent validity (with PedsQL/C‐HAQ subdomains) and discriminative validity (active/inactive disease) were assessed. Reliability of the item banks, short forms, and computerized adaptive testing (CAT) was expressed as the SE of theta (SE[θ]). Test–retest reliability was assessed using intraclass correlation coefficients (ICCs) and smallest detectable change.

Results

All item banks had sufficient overall GRM fit (CFI >0.95, TLI >0.95, RMSEA <0.08) and no item misfit (all S‐X²P > 0.001). High correlations (>0.70) were found between most PROMIS T scores and hypothesized PedsQL/C‐HAQ (sub)domains. Mobility, pain interference, and upper extremity item banks were able to discriminate between patients with active and inactive disease. Regarding reliability, PROMIS item banks outperformed legacy instruments. Post hoc CAT simulations outperformed short forms. Test–retest reliability was strong (ICC >0.70) for all full‐length item banks and short forms, except for the peer relationships item bank.

Conclusion

The pediatric PROMIS item banks displayed sufficient psychometric properties for Dutch children with JIA. PROMIS item banks are ready for use in clinical research and practice for children with JIA.

First Validation of the Full PROMIS Pain Interference and Pain Behavior Item Banks in Patients With Rheumatoid Arthritis

OBJECTIVE

Pain interference and pain behavior are highly relevant outcomes in patients with rheumatoid arthritis (RA). The Patient-Reported Outcomes Measurement Information System (PROMIS) is a universally applicable set of item banks measuring patient-reported health, and if applied as computerized adaptive tests (CATs), more efficiently and precisely than current instruments. The objective was to study the psychometric properties of the Dutch-Flemish PROMIS pain interference (PROMIS-PI) and the PROMIS pain behavior (PROMIS-PB) item banks in patients with RA.

METHODS

A total of 2,029 patients with RA completed the full PROMIS-PI (version 1.1, 40 items), and 1,554 patients completed the full PROMIS-PB (version 1.1, 39 items). The following psychometric properties were studied: unidimensionality, local dependence, monotonicity and graded response model (GRM) fit, cross-cultural validity (differential item functioning [DIF] for language [Dutch versus Flemish]), other forms of measurement invariance, construct validity, reliability, and floor and ceiling effects.

RESULTS

The PROMIS-PI and PROMIS-PB banks were sufficiently unidimensional (Omega-hierarchical [Omega-H] 0.99, 0.95, and explained common variance 0.95, 0.78, respectively), had negligible local dependence (0.3-1.4% of item pairs), good monotonicity (H 0.75, 0.46), and a good GRM model fit (no misfitting items). Furthermore, both item banks showed good cross-cultural validity (no DIF for language), measurement invariance (no DIF for age, sex, administration mode, and disease activity), good construct validity (all hypotheses met), high reliability (>0.90 in the range of patients with RA), and an absence of floor and ceiling effects (0% minimum or maximum score, respectively).

CONCLUSION

Both PROMIS-PI and PROMIS-PB banks showed good psychometric properties in patients with RA and can be used as CATs in research and clinical practice.

Changes in the ability to participate in and satisfaction with social roles and activities in patients in outpatient rehabilitation

Background

One of the main aims of rehabilitation is to improve participation. Patient-Reported Outcomes Measurement Information System (PROMIS®) item banks ‘Ability to Participate in Social roles and Activities, (PROMIS-APS) and ‘Satisfaction with Social Roles and Activities’ (PROMIS-SPS) are promising options to measure participation, but the literature on PROMIS measures of (satisfaction with) participation across diagnoses in rehabilitation is limited. Therefore, the objective of this study was to describe levels of and changes in participation, as assessed with the PROMIS-APS and the PROMIS-SPS short forms, of patients in outpatient rehabilitation.

Methods

This study had quantitative, observational design with assessments at admission and discharge. Consecutive patients treated between April and August 2018 receiving outpatient multidisciplinary rehabilitation were the population of this study. The following diagnosis categories were included: brain injury (e.g. stroke), spinal cord and nerve injury, neuromuscular disorder (e.g. lateral sclerosis), amputation, musculoskeletal condition (e.g. osteoarthritis) or heart or lung disease (e.g. myocardial infarction, chronic obstructive pulmonary disease). The main patient-reported outcomes (PRO) of this study were the short form of the PROMIS-APS (8 items, Dutch general population reference score 50.6 [SD 9.5]), and PROMIS-SPS (8 items, Dutch general population reference score 47.5 [SD 8.3].

Results

Of the 1279 patients invited, 777 (61%) completed the online forms at admission. Of those, 329 patients were invited at discharge, with 209 (64%) completing the forms. The mean (SD) T-scores of the PROMIS-APS and PROMIS-SPS were lower at admission (42.7 [SD 7.4]; (41.4 [SD 7.7]) and discharge (43.6 [SD 7.2]; (43.7 [SD 7.8]) than the Dutch general population. The change scores of the PROMIS-APS and PROMIS-SPS were 1.2 (95% CI 0.4–1.9; p = 0.004; effect size 0.16), and 2.4 (95% CI 1.6–3.2; p < 0.0001; effect size 0.31), respectively. In all diagnostic subgroups with > 30 paired measurements statistically significant improvements of PROMIS-APS, PROMIS-SPS or both were seen.

Conclusions

Patients undergoing outpatient rehabilitation had, both at admission and discharge, considerably lower PROMIS-APS and PROMIS-SPS T-scores short forms than the general Dutch population, and showed small T-score improvements at discharge.

Outcomes and potential mechanism of a protocol to optimize foot orthoses in patients with rheumatoid arthritis

Background

Foot problems are highly prevalent in patients with rheumatoid arthritis. Treatment of foot problems related to rheumatoid arthritis often consists of custom made foot orthoses. One of the assumed working mechanisms of foot orthoses is redistribution of plantar pressure by creating a larger weight bearing area. Overall, the reported treatment effect of foot orthoses on foot pain in rheumatoid arthritis is small to medium. Therefore, we developed a foot orthoses optimization protocol for evaluation and adaptation of foot orthoses by using the feedback of in-shoe plantar pressure measurements. The objectives of the present study were: 1) to evaluate the 3-months outcomes of foot orthoses developed according to the protocol on pain, physical functioning and forefoot plantar pressure in patients with foot problems related to rheumatoid arthritis, and 2) to determine the relationship between change in forefoot plantar pressure and change in pain and physical functioning.

Methods

Forty-five patients with foot problems related to rheumatoid arthritis were included and received foot orthoses developed according to the protocol. Outcome measures were assessed at baseline and after three months of wearing foot orthoses in 38 patients. Change scores and effect sizes (ES) were calculated for pain, physical functioning and plantar pressure. In a subgroup of patients with combined forefoot pain and high plantar pressure, the relationship between change in plantar pressure and change in pain and physical functioning was analyzed.

Results

In the total group of 38 patients, statistically significant changes in pain (ES 0.69), physical functioning (ES 0.82) and forefoot plantar pressure (ES 0.35) were found. In the subgroup (n = 23) no statistically significant relationships were found between change in plantar pressure and change in pain or physical functioning.

Conclusion

Foot orthoses developed according to a protocol for improving the plantar pressure redistribution properties lead to medium to large improvements in pain and physical functioning. The hypothesis that more pressure reduction would lead to better clinical outcomes could not be proven.

Development of a Patient-Reported Outcomes Measurement Information System (PROMIS®) short form for measuring physical function in geriatric rehabilitation patients

Purpose

To develop and test the validity of a Patient-Reported Outcomes Measurement Information System (PROMIS®) short form for measuring physical function of geriatric rehabilitation patients.

Methods

Experts selected items from the Dutch-Flemish PROMIS v1.2 Physical Function (PROMIS-PF) item bank and proposed new items to develop the PROMIS-PF short form for geriatric rehabilitation (PROMIS-PF-GR). Patients evaluated its content validity. Structural validity was assessed by evaluating unidimensionality (confirmatory, exploratory, and bi-factor analyses [criterion: Omega H > 0.80 and ECV > 0.60]), local independence (criterion: residual correlation < 0.20) ,and monotonicity (criterion: H_i-coefficient ≥ 0.30). Measurement invariance was assessed by evaluating Differential Item Functioning (DIF) between geriatric rehabilitation patients and people from the general population using ordinal logistic regression. Internal consistency was assessed by calculating Cronbach’s alpha (criterion: alpha ≥ 0.70).

Results

Experts selected 24 items from the PROMIS-PF item bank and proposed one new item which was not included in the short form. Patients considered the 24 items relevant and containing essential information. The PROMIS-PF-GR’s psychometric properties were evaluated in 207 patients (mean age ± SD, 80.0 ± 8.3 year; 58% female). The 24 items were found to be sufficiently unidimensional (Omega H = 0.82, ECV = 0.70), locally independent (98.7% item pairs), and monotone (all ≥ 0.32). Five items were flagged for DIF, but their impact on the total score was negligible. Cronbach’s alpha was 0.94.

Conclusion

The PROMIS-PF-GR was developed from the PROMIS-PF and has good content validity, structural validity, measurement invariance, and internal consistency in Dutch geriatric rehabilitation patients. We recommend to confirm the content validity of the PROMIS-PF-GR in other countries.

Graded response model fit, measurement invariance and (comparative) precision of the Dutch-Flemish PROMIS® Upper Extremity V2.0 item bank in patients with upper extremity disorders

BACKGROUND

The Dutch-Flemish PROMIS® Upper Extremity (DF-PROMIS-UE) V2.0 item bank was recently developed using Item Response Theory (IRT). Unknown for this bank are: (1) if it is legitimate to calculate IRT-based scores for short forms and Computerized Adaptive Tests (CATs), which requires that the items meet the assumptions of and fit the IRT-model (Graded Response Model [GRM]);(2) if it is legitimate to compare (sub) groups of patients using this measure, which requires measurement invariance; and (3) the precision of the estimated patients' scores for patients with different levels of functioning and compared to legacy measures. Aims were to evaluate (1) the assumptions of and fit to the GRM, (2) measurement invariance and (3) (comparative) precision of the DF-PROMIS-UE v2.0.

METHODS

Cross-sectional data were collected in Dutch patients with upper extremity disorders. Assessed were IRT-assumptions (unidimensionality [bi-factor analysis], local independence [residual correlations], monotonicity [coefficient H]), GRM item fit, measurement invariance (absence of Differential Item Functioning [DIF] due to age, gender, center, duration, and location of complaints) and precision (standard error of IRT-based scores across levels of functioning). To study measurement invariance for language [Dutch vs. English], additional US data were used. Legacy instruments were the Disability of the Arm, Shoulder and Hand (DASH), the QuickDASH and the Michigan Hand Questionnaire (MHQ).

RESULTS

In total 521 Dutch (mean age ± SD = 51 ± 17 years, 49% female) and 246 US patients (mean age ± SD = 48 ± 14 years, 69% female) participated. The DF-PROMIS-UE v2.0 item bank was sufficiently unidimensional (Omega-H = 0.80, Explained Common Variance = 0.68), had negligible local dependence (four out of 1035 correlations > 0.20), good monotonicity (H = 0.63), good GRM fit (no misfitting items) and demonstrated sufficient measurement invariance. Precise estimates (Standard Error < 3.2) were obtained for most patients (7-item short form, 88.5%; standard CAT, 91.3%; and, fixed 7-item CAT, 87.6%). The DASH displayed better reliability than the DF-PROMIS-UE short form and standard CAT, the QuickDASH displayed comparable reliability. The MHQ-ADL displayed better reliability than the DF-PROMIS-UE short form and standard CAT for T-scores between 28 and 50. For patients with low function, the DF-PROMIS-UE measures performed better.

CONCLUSIONS

The DF-PROMIS-UE v2.0 item bank showed sufficient psychometric properties in Dutch patients with UE disorders.

Higher body mass index is associated with lower foot health in patients with rheumatoid arthritis: baseline results of the Amsterdam-Foot cohort

Objective: Obesity is highly prevalent in patients with rheumatoid arthritis (RA), with likely impact on weight-bearing foot joints. We explored the associations between body mass index (BMI) and measures of foot health in patients with RA and foot complaints.Method: We examined patients with RA presenting for their first custom-made therapeutic footwear or foot orthoses. Domains of foot health comprised: foot pain, foot-related activity limitations, forefoot plantar pressure, foot synovitis, and foot deformity. In regression analyses, BMI was the independent variable and foot health domains were the dependent variables.Results: The cohort at baseline comprised 230 patients [mean ± sd age 58 ± 13 years, 80% female, mean ± sd disease duration 10 ± 9 years, and median (interquartile range) BMI 26.7 (23.5-30.1) kg/m²]. Small to modest statistically significant associations were found in the majority of the measures studied between a higher BMI and more foot pain, more foot-related activity limitations, higher in-shoe measured forefoot plantar pressure, and the presence of foot synovitis. No relationships were found between BMI and barefoot measured forefoot plantar pressure or foot deformity.Conclusion: BMI is negatively associated with foot health in patients with RA. Although the clinical relevance of our findings for an individual patient is not immediately obvious, future research should consider BMI as a potential therapeutic target to improve foot health.

A Smartphone App for Self-Monitoring of Rheumatoid Arthritis Disease Activity to Assist Patient-Initiated Care: Protocol for a Randomized Controlled Trial

Background

Telemedicine based on self-measurement of disease activity could be one of the key components to create the health care system of the future. Previous publications in various medical fields have shown that it is possible to safely telemonitor patients while reducing the number of outpatient clinic visits. For this purpose, we developed a mobile phone app for patients with rheumatoid arthritis (RA), which allows them to self-monitor their disease.

Objective

The objective of this study is to assess the safety and efficacy of self-initiated care assisted by a smartphone app in patients with RA.

Methods

This is a randomized controlled trial that will be performed for 1 year. A total of 176 patients with RA will be randomized to either self-initiated care with only one scheduled follow-up consultation assisted by our app or usual care. The coprimary outcome measures are the number of outpatient clinic consultations with a rheumatologist taking place during the trial period and the mean disease activity score as measured by the disease activity score 28 (DAS28) at 12 months. The secondary outcomes are patient satisfaction, adherence, patient empowerment, and cost evaluation of health care assisted by the app.

Results

Recruitment started in May 2019, and up to 18 months will be required for completion of recruitment. Thus far, 78 patients have been randomized, and thus far, experiences with the app have been positive. The study results are expected to be published by the end of 2021.

Conclusions

The completion of this study will provide important data regarding the following: (1) safety of self-initiated care supported by a smartphone app in terms of DAS28 and (2) efficacy of lowering health care usage with this new strategy of providing health care.

Trial Registration

Netherlands Trial Register NL7715; https://www.trialregister.nl/trial/7715

International Registered Report Identifier (IRRID)

DERR1-10.2196/15105

Factors Associated With Sleep Quality in Patients With Chronic Widespread Pain Attending Multidisciplinary Treatment

PURPOSE

(1) To investigate the prevalence of poor sleep quality and (2) to explore the associations between clinical, cognitive, and emotional factors and quality of sleep in patients with chronic widespread pain (CWP) receiving multidisciplinary treatment.

METHOD

Baseline data were used from 163 patients with CWP referred for multidisciplinary treatment. Linear regression models were used to assess the relationship of clinical (pain, fatigue, pain interference, and disability), emotional (anxiety, depression, and psychological distress), and cognitive factors (catastrophizing, acceptance, self-efficacy, kinesiophobia and illness beliefs) with sleep quality, as measured using the Pittsburgh Sleep Quality Index.

RESULTS

Poor sleep quality was found in 92% of the patients. The multivariable model showed that a higher level of fatigue (b = 1.77, standard error [SE] = 0.62, β = 0.21, t = 2.87, P < 0.01), psychological distress (b = 0.02, SE = 0.01, β = 0.27, t = 3.50, P < 0.01), and more concerns about the illness (b = 0.46, SE = 0.18, β = 0.20, t = 2.57, P = 0.01) were independently associated with poorer quality of sleep. The overall linear regression model explains 27.9% of sleep quality.

CONCLUSIONS

The high prevalence of poor sleep quality in patients with CWP referred for multidisciplinary treatment emphasizes the need to target sleep during treatment. Further research is needed to disentangle the cause-effect relationship between fatigue, psychological distress, and concerns about the illness and poor sleep (note: this abstract has been published before [Ann Rheum Dis. 2018;77:A1788]).

Evaluation of an educational course for primary care physiotherapists on comorbidity-adapted exercise therapy in knee osteoarthritis: an observational study

Objective

The objectives of the present study were to: (1) evaluate the effect of an educational course on competence (knowledge and clinical reasoning) of primary care physical therapists (PTs) in treating patients with knee osteoarthritis (KOA) and comorbidity according to the developed strategy; and (2) identify facilitators and barriers for usage.

Method

The present research was an observational study with a pretest‐posttest design using mixed methods. PTs were offered a postgraduate course consisting of e‐learning and two workshops (blended education) on the application of a strategy for exercise prescription in patients with KOA and comorbidity. Competences were measured by questionnaire on knowledge (administered before and 2 weeks after the course), and a patient vignette to measure clinical reasoning (administered before the course and after a 6 month period of treating patients). Facilitators and barriers for using the strategy were assessed by a questionnaire and semi‐structured interviews.

Results

Thirty‐four PTs were included. Competence (knowledge and clinical reasoning) improved significantly (p < 0.01). Fourteen out of 34 PTs had actually treated patients with KOA and comorbidity, during a 6‐month period. The strategy was found to be feasible in daily practice. The main barriers included the limited number of (self‐) referrals of patients, limited number of reimbursed treatment sessions by insurance companies and a suboptimal collaboration with (referring) physicians.

Conclusion

A blended course on exercise therapy for patients with KOA and comorbidity seems to improve PTs' competence through increasing knowledge and clinical reasoning skills. Identified barriers should be solved before large‐scale implementation of exercise therapy can take place in these complex patients.

Systematic review on the comparative effectiveness of foot orthoses in patients with rheumatoid arthritis

Background

Foot orthoses (FOs) are prescribed as an important conservative treatment option in patients with foot problems related to rheumatoid arthritis. However, a broad variation in FOs is used, both in clinical practice and in research. To date, there is no overview on the outcomes of the treatment with different kinds of FOs in patients with rheumatoid arthritis and a specific foot problem. The objectives of the present study were to summarize the comparative effectiveness of FOs in the treatment of various foot problems in patients with rheumatoid arthritis, on the primary outcomes foot function and foot pain, and the secondary outcomes physical functioning, health related quality of life, compliance, adverse events, the costs of FOs and patient satisfaction.

Methods

Studies comparing different kinds of FOs, with a presumed therapeutic effect, in the treatment of foot problems related to rheumatoid arthritis were included. A literature search was conducted in The Cochrane Central Registry for Controlled Trials (CENTRAL), PubMed, EMBASE and PEDro up to May 18th, 2018. Data was meta-analyzed, when this was not possible qualitative data analysis was performed.

Results

Ten studies were identified, with a total number of 235 patients. These studies made a comparison between different materials used (soft versus semi-rigid), types of FOs (custom-made versus ready-made; total-contact versus non-total contact), or modifications applied (metatarsal bars versus domes). Also, different techniques to construct custom-made FOs were compared (standard custom-molding techniques versus more sophisticated techniques). A medium effect for (immediate) reduction of forefoot plantar pressure was found in favor of treatment with soft FOs compared to semi-rigid FOs (SMD 0.60, 95% CI 0.07-1.14; P = 0.03; 28 participants). Other comparisons between FOs resulted in non-significant effects or inconclusive evidence for one kind of FOs over the other.

Conclusions

Foot orthoses made of soft materials may lead to more (immediate) forefoot plantar pressure reduction compared to foot orthoses constructed of semi-rigid materials. Definitive high quality RCTs, with adequate sample sizes and long-term follow-up, are needed to investigate the comparative (cost-) effectiveness of different kinds of foot orthoses for the treatment of foot problems related to rheumatoid arthritis.

Psychometric properties of the Dutch-Flemish Patient-Reported Outcomes Measurement Information System Pain Behavior item bank in patients with musculoskeletal complaints

We studied the psychometric properties of the 39-item v1.1 Dutch-Flemish Patient-Reported Outcomes Measurement Information System Pain Behavior item bank in a sample of 1,602 patients with musculoskeletal complaints. We evaluated the assumptions of the underlying item response theory (IRT) model (unidimensionality and local dependency with confirmatory factor analyses), and monotonicity with scalability coefficients). We studied the IRT model fit of all items and estimated the item parameters of the IRT model. Differential item functioning (DIF) was studied for age and gender, and DIF for language was studied as a measure of cross-cultural validity. Confirmatory factor analyses showed suboptimal fit of a unidimensional model, but a bifactor model showed low risk of bias when a unidimensional model was assumed (Omega H = .92, explained common variance of .70). Fifteen item pairs (2%) were locally dependent. Five items showed poor scalability. All items fitted the IRT model; slope parameters ranged from .60 to 2.00, and threshold parameters from -2.05 to 6.80. One item showed DIF for age, 1 item DIF for gender, and 5 items showed DIF for language, but the impact on total scores was low. Our study shows limitations of the Dutch-Flemish Patient-Reported Outcomes Measurement Information System Pain Behavior item bank when used in a primary care population with musculoskeletal complaints. PERSPECTIVE: We studied the psychometric properties of the Dutch-Flemish Patient-Reported Outcomes Measurement Information System Pain Behavior item bank in a large primary care population of patients with musculoskeletal complaints. It showed that the Pain Behavior item bank has limitations when used in this population.

Test-retest reliability of the special interest group on amputation medicine/Dutch working group on amputations and prosthetics mobility scale, in persons wearing a prosthesis after a lower-limb amputation

Purpose: To assess the test-retest reliability of the Special Interest Group on Amputation Medicine Mobility Scale/Dutch Working Group on Amputations and Prosthetics, better known as SIGAM/WAP mobility scale, in persons with a lower-limb amputation.Method: Longitudinal study at the outpatient departments of a rehabilitation center and a university medical center. Persons with a lower-limb amputation, wearing a prosthesis, were assessed at the end of their multidisciplinary rehabilitation treatment twice, with a 3-week interval, by the same practitioner. Test-retest reliability was quantified using the intraclass correlation coefficient for agreement.Results: Eighty persons participated (mean age ± SD, 61 ± 15 years; 61% men; 76% vascular cause of amputation; 70% able to walk >50m). Fifty-one of them rated themselves to be stable with respect to their mobility and their intraclass correlation coefficient was 0.90 (95% confidence intervals 0.84-0.94).Conclusions: The Special Interest Group on Amputation Medicine Mobility Scale/Dutch Working Group on Amputations and Prosthetics had, at the outpatient departments of a rehabilitation center and a university medical center, excellent test-retest reliability in persons wearing a prosthesis after a lower-limb amputation.Implications for rehabilitationThe Special Interest Group on Amputation Medicine/Dutch Working Group on Amputations and Prosthetics Mobility Scale was developed to classify mobility after a lower-limb amputation and wearing a prosthesis.The Dutch translation of this mobility scale has excellent test-retest reliability.

Forefoot pathology in relation to plantar pressure distribution in patients with rheumatoid arthritis: A cross-sectional study in the Amsterdam Foot cohort

BACKGROUND

In patients with rheumatoid arthritis (RA), both high and low forefoot plantar pressures have been reported. Better understanding of pathology in the forefoot associated with altered pressure distribution in patients with RA could help to better formulate and specify goals for treatment with foot orthoses or therapeutic footwear.

OBJECTIVES

To investigate the association of plantar pressure with disease activity and deformity in the forefoot in patients with rheumatoid arthritis and forefoot symptoms.

METHODS

A cross sectional study, using data of 172 patients with rheumatoid arthritis and forefoot symptoms, was conducted. Peak pressure (PP) and pressure time integral (PTI) in the forefoot were measured with a pressure platform. Forefoot deformity was assessed using the Platto score. Forefoot disease activity was defined as swelling and/or pain assessed by palpation of the metatarsophalangeal joints. The forefoot was divided in a medial, central and lateral region, in which the following conditions could be present: 1) no pathology, 2) disease activity, 3) deformity or 4) disease activity and deformity. A multilevel analysis was performed using condition per forefoot region as independent variable and PP or PTI in the corresponding region as dependent variable.

RESULTS

Statistically significant higher plantar pressures were found in forefoot regions with deformities (RR 1.2, CI 1.1-1.3, P<0.0001), compared to forefoot regions without forefoot pathology. No significant differences in plantar pressures were found when solely forefoot disease activity was present in forefoot regions.

SIGNIFICANCE

Forefoot deformities are related to higher plantar pressures measured in the corresponding forefoot regions. The absence of an association between local disease activity and plantar pressure might be explained by the low prevalence of metatarsophalangeal joint pain or swelling. Future research with sensitive imaging measures to detect disease activity is recommended to reveal the effect of forefoot disease activity on plantar pressure.

Is a model of stratified exercise therapy by physical therapists in primary care feasible in patients with knee osteoarthritis? : a mixed methods study

OBJECTIVES

To explore the feasibility of a newly developed model of stratified exercise therapy in primary care for patients with knee osteoarthritis (OA).

DESIGN

Mixed method design (process, outcome and qualitative evaluation).

SETTING

Six physical therapy practices in primary care around Amsterdam.

PARTICIPANTS

Fifty eligible patients with knee OA, visiting one of the participating physical therapists (PTs).

INTERVENTION

Patients were allocated to a subgroup based on a simple stratification tool and received subgroup-specific, protocolized, 4-month, exercise therapy.

MAIN OUTCOME MEASURES

Feasibility of this model of stratified exercise therapy was explored by multiple process parameters, outcome measures (physical functioning and knee pain; at baseline and 4-months follow-up) and experiences from patients and PTs.

RESULTS

From 97 potentially eligible patients, fifty patients were included and allocated to the 'high muscle strength subgroup' (n=17), 'depression subgroup' (n=4), 'obesity subgroup' (n=6) or 'low muscle strength subgroup' (n=23). Three patients dropped out during the study period. PTs provided relatively low numbers of sessions (on average 10 sessions), although exceedance of the recommended maximum number of sessions did occur frequently. We found clinically relevant improvements on physical functioning and knee pain (P<0.001 for both) for the total group. In general, the model of stratified exercise therapy was considered to be easily applicable and of added value for daily practice.

CONCLUSIONS

Our model of stratified exercise therapy seems to be feasible in primary care, although a number of limitations were reported. Future research should determine the (cost-)effectiveness of an adapted model, compared to usual, non-stratified exercise therapy.

Validation of two PROMIS item banks for measuring social participation in the Dutch general population

BACKGROUND

The Patient-Reported Outcomes Measurement Information System (PROMIS) item banks 'Ability to Participate in Social Roles and Activities' (35 items) and 'Satisfaction with Social Roles and Activities' (44 items) were developed to measure (satisfaction with) participation more efficiently and precisely than current instruments, by using Computerized Adaptive Testing (CAT). We validated these item banks in a Dutch general population.

METHODS

Participants in an internet panel completed both item banks. Unidimensionality, local dependence, monotonicity, Graded Response Model item fit, Differential Item Functioning (DIF) for age, gender, education, region, ethnicity, and language (Dutch compared to US Social Supplement), and reliability were assessed.

RESULTS

A representative Dutch sample of 1002 people participated. We found for the Ability to Participate and Satisfaction with Participation item banks, respectively, sufficient unidimensionality (CFI: 0.971, 0.960; TLI: 0.970, 0.958; RMSEA: 0.108, 0.108), no local dependence, sufficient monotonicity (H: 0.75, 0.73), good item fit (2 out of 35 items, 1 out of 44 items with S-X2p-value < 0.001). No DIF was found. We found a reliability of at least 0.90 with simulated CATs in 86% and 94% of the participants with on average 4.7 (range 2-12) and 4.3 (range 3-12) items, respectively.

DISCUSSION

The PROMIS participation item banks showed sufficient psychometric properties in a general Dutch population and can be used as CAT. PROMIS CATs allow reliable and valid measurement of participation in an efficient and user-friendly way with limited administration time.

The immediate effect of a soft knee brace on dynamic knee instability in persons with knee osteoarthritis

Objectives

Wearing a soft knee brace has been shown to reduce self-reported knee instability in persons with knee OA. There is a need to assess whether a soft knee brace has a beneficial effect on objectively assessed dynamic knee instability as well. The aims of the study were to evaluate the effect of a soft knee brace on objectively assessed dynamic knee instability and to assess the difference in effect between a non-tight and a tight soft knee brace in persons with knee OA.

Methods

Thirty-eight persons with knee OA and self-reported knee instability participated in a laboratory study. A within-subject design was used comparing no brace vs brace and comparing a non-tight vs a tight brace. The primary outcome measure was dynamic knee instability, expressed by the perturbation response (PR). The PR reflects deviation in the mean knee varus-valgus angle during level walking after a controlled mechanical perturbation. Linear mixed-effect model analysis was used to evaluate the effect of a brace on dynamic knee instability.

Results

Wearing a brace significantly reduced the PR compared with not wearing a brace (B = -0.16, P = 0.01). There was no difference between a non-tight and a tight brace (B = -0.03, P = 0.60).

Conclusion

This study is the first to report that wearing a soft knee brace reduces objectively assessed dynamic knee instability in persons with knee OA. Wearing a soft brace results in an objective improvement of knee instability beyond subjectively reported improvement.

Trial registration

Nederlands Trial register (trialregister.nl) NTR6363.

Decreased Pain and Improved Dynamic Knee Instability Mediate the Beneficial Effect of Wearing a Soft Knee Brace on Activity Limitations in Patients With Knee Osteoarthritis

OBJECTIVE

To evaluate whether improvement of proprioception, pain, or dynamic knee instability mediates the effect of wearing a soft knee brace on activity limitations in patients with knee osteoarthritis (OA).

METHODS

We conducted an analysis of data for 44 patients with knee OA who were enrolled in a laboratory-based trial evaluating the effect of wearing a commercially available soft knee brace. Activity limitations were assessed with the 10-meter walk test and the Get Up and Go test. Knee joint proprioception was assessed by an active joint position sense test; pain was assessed on a numeric rating scale (NRS) (range 0-10); pressure pain threshold (PPT) was assessed with a hand-held pressure algometer; dynamic knee instability was expressed by the perturbation response, i.e., a measure reflecting a deviation in mean knee varus-valgus angle after a controlled mechanical perturbation on a treadmill, with respect to level walking. Mediation analysis was conducted using the product of coefficients approach. Confidence intervals were calculated with a bootstrap procedure.

RESULTS

A decrease in pain (scored on an NRS) and a decrease in dynamic knee instability mediated the effect of wearing a soft knee brace on the reduction of activity limitations (P < 0.05), while changes in proprioception and PPT did not mediate this effect (P > 0.05).

CONCLUSION

This study shows that decreased pain and reduced dynamic knee instability are pathways by which wearing a soft knee brace decreases activity limitations in patients with knee OA.

Evaluation of the wear-and-tear scale for therapeutic footwear, results of a generalizability study

OBJECTIVE

Therapeutic footwear is often prescribed at considerable cost. Foot-care specialists normally assess the wear-and-tear of therapeutic footwear in order to monitor the adequacy of the prescribed footwear and to gain an indicator of its use. We developed a simple, rapid, easily applicable indicator of wear-and-tear of therapeutic footwear: the wear-and-tear scale. The aim of this study was to investigate the intra- and inter-rater reliability of the wear-and-tear scale.

METHODS

A test set of 100 therapeutic shoes was assembled; 24 raters (6 inexperienced and 6 experienced physiatrists, and 6 inexperienced and 6 experienced orthopaedic shoe technicians) rated the degree of wear-and-tear of the shoes on the scale (range 0-100) twice on 1 day with a 4-h interval (short-term) and twice over a 4-week interval (long-term). Generalizability theory was applied for the analysis.

RESULTS

Short-term, long-term and overall intra-rater reliability was excellent (coefficients 0.99, 0.99 and 0.98; standard error of measurement (SEM) 2.6, 2.9 and 3.9; smallest detectable changes (SDC) 7.3, 8.0 and 10.8, respectively). Inter-rater reliability between professions, experience and inexperienced raters, and overall was excellent (coefficients 0.97, 0.98 and 0.93; SEM 4.9, 4.5, and 8.1; SDC 13.7, 12.4 and 22.5, respectively).

CONCLUSION

The wear-and-tear scale has excellent intra-rater, inter-rater, and overall reliability.

Proprioception mediates the association between systemic inflammation and muscle weakness in patients with knee osteoarthritis: Results from the Amsterdam Osteoarthritis cohort

OBJECTIVES

To determine whether systemic inflammation is associated with poor proprioception; to confirm that systemic inflammation is associated with muscle weakness; and to determine whether poor proprioception mediates the association between systemic inflammation and muscle weakness in knee osteoarthritis.

DESIGN

Cross-sectional study.

SUBJECTS

A total of 689 participants with knee osteoarthritis from the Amsterdam Osteoarthritis (AMS-OA) cohort.

METHODS

Systemic inflammation was assessed by erythrocyte sedimentation rate, knee proprioception by determining the joint motion detection threshold, and muscle strength with an isokinetic dynamometer. Linear regression models were used to estimate direct associations between systemic inflammation, proprioception and muscle strength, and the indirect association (mediation) between systemic inflammation and muscle strength via proprioception adjusted for potential confounders.

RESULTS

Higher erythrocyte sedimentation rates were associated with poor proprioception (p = 0.022). Poor proprioception (p < 0.001) and higher erythrocyte sedimentation rates (p < 0.001) were associated with muscle weakness. Poor proprio-ception mediated the association between systemic inflammation and muscle weakness (p = 0.035).

CONCLUSION

Results suggest that systemic inflammation is associated with poor proprioception in knee osteoarthritis. Poor proprioception may be a path-way through which systemic inflammation is associated with muscle weakness in patients with knee osteoarthritis.

Psychometric properties of the PROMIS Physical Function item bank in patients receiving physical therapy

OBJECTIVES

The Patient-Reported Outcomes Measurement Information System (PROMIS) is a universally applicable set of instruments, including item banks, short forms and computer adaptive tests (CATs), measuring patient-reported health across different patient populations. PROMIS CATs are highly efficient and the use in practice is considered feasible with little administration time, offering standardized and routine patient monitoring. Before an item bank can be used as CAT, the psychometric properties of the item bank have to be examined. Therefore, the objective was to assess the psychometric properties of the Dutch-Flemish PROMIS Physical Function item bank (DF-PROMIS-PF) in Dutch patients receiving physical therapy.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

805 patients >18 years, who received any kind of physical therapy in primary care in the past year, completed the full DF-PROMIS-PF (121 items).

METHODS

Unidimensionality was examined by Confirmatory Factor Analysis and local dependence and monotonicity were evaluated. A Graded Response Model was fitted. Construct validity was examined with correlations between DF-PROMIS-PF T-scores and scores on two legacy instruments (SF-36 Health Survey Physical Functioning scale [SF36-PF10] and the Health Assessment Questionnaire Disability-Index [HAQ-DI]). Reliability (standard errors of theta) was assessed.

RESULTS

The results for unidimensionality were mixed (scaled CFI = 0.924, TLI = 0.923, RMSEA = 0.045, 1th factor explained 61.5% of variance). Some local dependence was found (8.2% of item pairs). The item bank showed a broad coverage of the physical function construct (threshold-parameters range: -4.28-2.33) and good construct validity (correlation with SF36-PF10 = 0.84 and HAQ-DI = -0.85). Furthermore, the DF-PROMIS-PF showed greater reliability over a broader score-range than the SF36-PF10 and HAQ-DI.

CONCLUSIONS

The psychometric properties of the DF-PROMIS-PF item bank are sufficient. The DF-PROMIS-PF can now be used as short forms or CAT to measure the level of physical function of physiotherapy patients.

Nonlinear relationship between isokinetic muscle strength and activity limitations in patients with knee osteoarthritis: Results of the Amsterdam-Osteoarthritis cohort

OBJECTIVE

To investigate whether relationships between upper leg muscle strength and activity limitations are non-linear in patients with knee osteoarthritis, and, if so, to determine muscle strength thresholds for limitations in daily activities.

DESIGN

Baseline data were used for 562 patients with knee osteoarthritis in the Amsterdam-Osteoarthritis cohort. Upper leg muscle strength (Nm/kg) was measured isokinetically. Activity limitations were measured with the timed Get Up and Go test and timed Stair Climb Test, subdivided into stair-ascent and stair-descent. Linear and non-linear relationships between muscle strength and activity limitations were evaluated, and thresholds were determined.

RESULTS

Non-linear models improved model fit compared with linear models. The improvement in percentage variance accounted for was 5.9, 8.2 and 5.2 percentage points for the timed Get Up and Go, stair-ascent and stair-descent times, respectively. Muscle strength thresholds were 0.93 Nm/kg (95% confidence interval (95% CI) 0.82-1.04), 0.89 Nm/kg (95% CI 0.77-1.02) and 0.97 Nm/kg (95% CI 0.85-1.11) for relationships with timed Get Up and Go, stair-ascent and stair-descent times, respectively.

CONCLUSION

In patients with knee osteoarthritis, relationships between muscle strength and activity limitations are non-linear. Patients with muscle strength below the described thresholds might benefit more from muscle strength training to reduce limitations in daily activities than would patients with muscle strength above the thresholds. Further research is needed to assess the clinical value of the thresholds determined.

The immediate effect of a soft knee brace on pain, activity limitations, self-reported knee instability, and self-reported knee confidence in patients with knee osteoarthritis

Background

We aimed to (i) evaluate the immediate effect of a soft knee brace on pain, activity limitations, self-reported knee instability, and self-reported knee confidence, and (ii) to assess the difference in effect between a non-tight and a tight soft brace in patients with knee osteoarthritis (OA).

Methods

Forty-four patients with knee OA and self-reported knee instability participated in the single-session, laboratory, experimental study. A within-subject design was used, comparing a soft brace with no brace, and comparing a non-tight with a tight soft brace. The outcome measures were pain, self-reported knee instability and knee confidence during level and perturbed walking on the treadmill and activity limitations (10-m walk test and the get up and go (GUG) test). Linear mixed-effect model analysis for continuous outcomes and logistic generalized estimating equations for categorical outcomes were used to evaluate the effect of wearing a soft brace.

Results

Wearing a soft brace significantly reduced pain during level walking (B − 0.60, P = 0.001) and perturbed walking (B − 0.80, P < 0.001), reduced the time to complete the 10-m walk (B − 0.23, P < 0.001) and the GUG tests (B − 0.23, P = 0.004), reduced self-reported knee instability during level walking (OR 0.41, P = 0.002) and perturbed walking (OR 0.36, P < 0.001), and reduced lack of confidence in the knees during level walking (OR 0.45, P < 0.001) and perturbed walking (OR 0.56, P < 0.001), compared with not wearing a soft brace. There was no difference in effects between a non-tight and tight brace, except for the 10-m walk test. Wearing a tight brace significantly reduced the time to complete the 10-m walk test in comparison with wearing a non-tight brace (B − 0.11, P = 0.03).

Conclusion

The results of this study indicate that a soft brace is an efficacious intervention targeting pain, activity limitations, self-reported knee instability, and knee confidence in the immediate term in patients with knee OA. Further studies are needed evaluating the mode of action based on exerted pressure, and on the generalization to functioning in daily life.

Trial registration

trialregister.nl, NTR6363. Retrospectively registered on 15 May 2017.

Analgesic use in patients with knee and/or hip osteoarthritis referred to an outpatient center: a cross-sectional study within the Amsterdam Osteoarthritis Cohort

Although analgesics are widely recommended in current guidelines, underuse and inadequate prescription of analgesics seem to result in suboptimal treatment effects in patients with knee and/or hip osteoarthritis (OA). This study aimed (i) to describe the use of analgesics; and (ii) to determine factors that are related to analgesic use in patients with knee and/or hip OA referred to an outpatient center. A cross-sectional study with data from 656 patients with knee and/or hip OA referred to an outpatient center (Amsterdam Osteoarthritis (AMS-OA) cohort) was conducted. Self-reported use of analgesic (yes/no) was administered and subdivided into acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs, including coxibs) and opioids. Logistic regression analyses were performed to analyze the association between analgesic use and disease-related, predisposing and enabling factors. Analgesic use was reported by 63% of the patients, with acetaminophen, NSAIDs and opioid use reported by 50, 30 and 12%, respectively. Factors related to analgesic use were higher pain severity, longer duration of symptoms, higher radiographic hip OA severity, overweight/obesity and psychological distress. These factors explained 21% of the variance of analgesic use. More than one-third of patients with established knee and/or hip OA referred to an outpatient center did not use any analgesics. Although multiple, mostly disease-related associated factors were found, analgesic use remained predominantly unexplained. Our study seems to indicate that prescription of analgesics should be guided more dominantly by clinical symptoms and needs, and preceded by a thorough shared decision-making process between patient and physician.

Association of Somatic Comorbidities and Comorbid Depression With Mortality in Patients With Rheumatoid Arthritis: A 14-Year Prospective Cohort Study

OBJECTIVE

Patients with rheumatoid arthritis (RA) have a significantly increased risk of mortality compared with the general population. One of the most important predictors for mortality is somatic comorbidity. Moreover, studies have demonstrated that comorbid depression is associated with mortality. Which specific comorbidities are associated with mortality is less investigated. The purpose of this study was to investigate the association of a wide range of comorbidities with mortality in patients with RA.

METHODS

Longitudinal data over a 14-year period were collected from 882 patients with RA. Data were assessed with questionnaires. The mortality status was obtained from the Statistics Netherlands for the period 1996-2011 for 99% of the patients. Somatic comorbidity was assessed in 1997, 1998, 1999, and 2008 and measured by a national population-based questionnaire including 20 chronic diseases. Comorbid depression was assessed in 1997, 1998, and 1999 and measured with the Center for Epidemiologic Studies Depression Scale. Cox regression was used to study the relationship between comorbidity and mortality.

RESULTS

At baseline, 72% of the patients were women. The mean ± SD age was 59.3 ± 14.8 years, and the median (interquartile range) disease duration was 5.0 (2.0-14.0) years. A total of 345 patients died during the study period. Comorbidities that were associated with mortality were circulatory conditions (hazard ratio [HR] 1.60 [95% confidence interval (95% CI) 1.15-2.22]), respiratory conditions (HR 1.43 [95% CI 1.09-1.89]), cancer (HR 2.00 [95% CI 1.28-3.12]), and depression (HR 1.35 [95% CI 1.06-1.72]).

CONCLUSION

Comorbid circulatory conditions, respiratory conditions, cancer, and depression are associated with mortality among patients with RA. Careful monitoring of these comorbidities during the course of the disease and adequate referral may improve health outcomes and chances of surviving.

The Dutch-Flemish PROMIS Physical Function item bank exhibited strong psychometric properties in patients with chronic pain

OBJECTIVE

The objective of this study was to assess the psychometric properties of the Dutch-Flemish Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function item bank in Dutch patients with chronic pain.

STUDY DESIGN AND SETTING

A bank of 121 items was administered to 1,247 Dutch patients with chronic pain. Unidimensionality was assessed by fitting a one-factor confirmatory factor analysis and evaluating resulting fit statistics. Items were calibrated with the graded response model and its fit was evaluated. Cross-cultural validity was assessed by testing items for differential item functioning (DIF) based on language (Dutch vs. English). Construct validity was evaluated by calculation correlations between scores on the Dutch-Flemish PROMIS Physical Function measure and scores on generic and disease-specific measures.

RESULTS

Results supported the Dutch-Flemish PROMIS Physical Function item bank's unidimensionality (Comparative Fit Index = 0.976, Tucker Lewis Index = 0.976) and model fit. Item thresholds targeted a wide range of physical function construct (threshold-parameters range: -4.2 to 5.6). Cross-cultural validity was good as four items only showed DIF for language and their impact on item scores was minimal. Physical Function scores were strongly associated with scores on all other measures (all correlations ≤ -0.60 as expected).

CONCLUSION

The Dutch-Flemish PROMIS Physical Function item bank exhibited good psychometric properties. Development of a computer adaptive test based on the large bank is warranted.