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).

Dutch reference values for the Patient-Reported Outcomes Measurement Information System Scale v1.2 - Global Health (PROMIS-GH).

BACKGROUND: To add context to the impact of medical conditions, it is important to interpret and compare health outcomes across studies and populations. We aimed to determine Dutch reference values for the Patient-Reported Outcomes Measurement Information System Scale v1.2 - Global Health (PROMIS-GH). METHODS: The PROMIS-GH, also referred to as PROMIS-10, was completed by 4370 Dutch persons, representative for the 2016 Dutch population. T-scores for the mental health (GMH) and physical health (GPH) subscales, and their shorter two-item subscales, were calculated for the entire population, age groups and gender. T-scores for GMH and GPH were compared to the US reference population, representative for the 2000 US general population. Interpretability thresholds for poor, fair, good, very good and excellent GPH and GMH were calculated based on T-scores of participants, which were categorized into five groups based on their response to item Global01. For each group the mean GPH and GMH T-score was calculated and the midpoint between two adjacent means was identified, resulting in thresholds. Thresholds based on the Dutch data were compared to US thresholds. RESULTS: The Dutch population had a GMH T-score of 44.7 and a GPH T-score of 45.2, both substantially worse than the US reference population T-score of 50. Lower T-scores were also found for age-range and gender subpopulations. Dutch GMH and GPH interpretability thresholds were mostly not substantially different compared to the US thresholds, although the Dutch threshold between fair and poor mental health was considerably higher (29 vs. 38). CONCLUSIONS: This study reports reference values for the PROMIS-GH scale for the Dutch general population, including age-range and gender subpopulations. These reference values provide an important tool for healthcare professionals and researchers to better evaluate and interpret patient-reported mental health and physical health. Scores are notably worse than the US reference values. The exact reason for this remains subject for further research, although possibilities for the differences are discussed, including the presence of differential item functioning and the representativeness and recentness of the data.

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.

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.

Differential item functioning of the PROMIS physical function, pain interference, and pain behavior item banks across patients with different musculoskeletal disorders and persons from the general population.

PURPOSE: To investigate the validity of comparisons across patients with different musculoskeletal disorders and persons from the general population by evaluating differential item functioning (DIF) for the PROMIS physical function (PROMIS-PF), pain interference (PROMIS-PI), and pain behavior (PROMIS-PB) item banks. METHODS: Patients with chronic pain, rheumatoid arthritis (RA), or osteoarthritis (OA); patients receiving physiotherapy (PT); and persons from the Dutch general population completed the full Dutch-Flemish PROMIS-PF (121-items), PROMIS-PI (40-items), or PROMIS-PB (39-items) banks. DIF was assessed with ordinal logistic regression models and McFadden's pseudo R2-change of ≥ 2% as critical value. The impact of DIF on item scores and the T-scores per bank was examined by inspecting item characteristic curves (ICCs) and test characteristic curves (TCCs). RESULTS: 2762 patients with chronic pain, 2029 with RA, 1247 with OA, 805 receiving PT, and 1310 healthy persons participated. For the PROMIS-PF, 25 out of 121 items were flagged for DIF, of which 10 items were flagged in multiple comparisons. For the PROMIS-PI, only 2 out of 40 items were flagged for DIF and for the PROMIS-PB, only 3 out of 39 items. Most DIF items had R2 values just above the critical value of 2% and all showed uniform DIF. The ICCs and TCCs showed that the magnitude and impact of DIF on the item and T-scores were negligible. CONCLUSIONS: This study supports the universal applicability of PROMIS across (patient) populations. Comparisons across patients with different musculoskeletal disorders and persons from the general population are valid, when applying the PROMIS-PF, PROMIS-PI, and PROMIS-PB banks.

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.

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.

Calibration and Validation of the Dutch-Flemish PROMIS Pain Interference Item Bank in Patients with Chronic Pain.

The Dutch-Flemish PROMIS Group translated the adult PROMIS Pain Interference item bank into Dutch-Flemish. The aims of the current study were to calibrate the parameters of these items using an item response theory (IRT) model, to evaluate the cross-cultural validity of the Dutch-Flemish translations compared to the original English items, and to evaluate their reliability and construct validity. The 40 items in the bank were completed by 1085 Dutch chronic pain patients. Before calibrating the items, IRT model assumptions were evaluated using confirmatory factor analysis (CFA). Items were calibrated using the graded response model (GRM), an IRT model appropriate for items with more than two response options. To evaluate cross-cultural validity, differential item functioning (DIF) for language (Dutch vs. English) was examined. Reliability was evaluated based on standard errors and Cronbach's alpha. To evaluate construct validity correlations with scores on legacy instruments (e.g., the Disabilities of the Arm, Shoulder and Hand Questionnaire) were calculated. Unidimensionality of the Dutch-Flemish PROMIS Pain Interference item bank was supported by CFA tests of model fit (CFI = 0.986, TLI = 0.986). Furthermore, the data fit the GRM and showed good coverage across the pain interference continuum (threshold-parameters range: -3.04 to 3.44). The Dutch-Flemish PROMIS Pain Interference item bank has good cross-cultural validity (only two out of 40 items showing DIF), good reliability (Cronbach's alpha = 0.98), and good construct validity (Pearson correlations between 0.62 and 0.75). A computer adaptive test (CAT) and Dutch-Flemish PROMIS short forms of the Dutch-Flemish PROMIS Pain Interference item bank can now be developed.

Effect of robotic gait training on cardiorespiratory system in incomplete spinal cord injury.

The objectives in this study were to investigate the effect of robot-assisted gait training on cardiorespiratory fitness in subjects with motor incomplete spinal cord injury and document the exercise intensity of robotic walking in comparison with the recommended guidelines. Ten patients followed a 24-session training program with a robotic gait orthosis in addition to physiotherapy sessions completed within 10 to 16 wk. Cardiorespiratory fitness was determined in a graded arm crank exercise test before and after the training program. To assess the intensity of robot-assisted walking, oxygen consumption (VO2) and heart rate (HR) were measured during a training session early in and at the end of the training program, and exercise intensity measures (percentage of VO2 reserve [%VO2R], percentage of HR reserve [%HRR], and metabolic equivalents [METs]) were calculated. Whereas no changes were found in peak VO2, the resting and submaximal HR at a constant work load were significantly lower after training. Most subjects exercised at low intensity (<30%VO2R, <30%HRR, <3.0 METs), and only two subjects exercised at moderate intensity (>3.0 METs). In spite of the low exercise intensity of the training program and no changes in peak VO2, robot-assisted gait training induced some improvement in cardiorespiratory fitness, as suggested by lower resting and submaximal HR values.