Measuring the impact of multiple sclerosis: Enhancing the measurement performance of the Multiple Sclerosis Impact Scale (MSIS-29) using Rasch Measurement Theory (RMT)

Physical and psychological aspects of multiple sclerosis: Revisiting the Multiple Sclerosis Impact Scale (MSIS-29)

BACKGROUND

The MSIS-29 measures the physical and psychological impact of MS.

OBJECTIVE

The associations between MSIS-29 domains and demographic/clinical aspects were examined and trajectories analysed over time.

METHODS

Data were collected in the Trajectories of Outcome in Neurological Conditions study for a diverse population of people with MS, with follow-up for up to 5 years. Following Rasch analysis, minimal important change (MIC) was computed for ensuing total, physical and psychological domains.

RESULTS

Fit to the Rasch model using data from 5921 participants validated physical, psychological and total domains, and the conversion table transforms raw scores to interval-level metric equivalents. These domains showed significant differences across demographic (age, gender, employment, education, and marital status) and clinical (subtype, treatment, and duration) factors with large effect sizes. The MIC scores were physical: 9.1, total: 14.1, which were both above measurement error, and psychological: 5.5 which was not, so 1.6% of participants reported psychological change which was clinically important but not statistically significant. Trajectory analysis showed three groups, one stable and two with significant slopes, improving and deteriorating.

CONCLUSION

The MSIS-29 has shown adequate fit to the Rasch model after accommodating problems with local item dependency, through a bi-factor solution. The domains showed good discrimination across key factors.

Establishing clinically meaningful within-individual improvement thresholds for eight patient-reported outcome measures in people with relapsing-remitting multiple sclerosis

BACKGROUND

As disease-modifying therapies do not reverse the course of multiple sclerosis (MS), assessment of therapeutic success involves documenting patient-reported outcomes (PROs) concerning health-related quality of life, disease and treatment-related symptoms, and the impact of symptoms on function. Interpreting PRO data involves going beyond statistical significance to calculate within-patient meaningful change scores. These thresholds are needed for each PRO in order to fully interpret the PRO data. This analysis of PRO data from the PROMiS AUBAGIO study, which utilized 8 PRO instruments in teriflunomide-treated relapsing-remitting MS (RRMS) patients, was designed to estimate clinically meaningful within-individual improvement thresholds in the same manner, for 8 PRO instruments.

RESULTS

The analytical approach followed a triangulation exercise that considered results from anchor- and distribution-based methods and graphical representations of empirical cumulative distribution functions in PRO scores in groups defined by anchor variables. Data from 8 PRO instruments (MSIS-29 v2, FSMC, MSPS, MSNQ, TSQM v1.4, PDDS, HRPQ-MS v2, and HADS) were assessed from 434 RRMS patients. For MSIS-29 v2, FSMC, MSPS, and MSNQ total scores, available anchor variables enabled both anchor- and distribution-based methods to be applied. For instruments with no appropriate anchor available, distribution-based methods were applied. A recommended value for meaningful within-individual improvement was defined by comparing mean change in PRO scores between participants showing improvement of one or two categories in the anchor variable or those showing no change. A "lower bound" estimate was calculated using distribution-based methods. An improvement greater than the lower-bound estimate was considered "clinically meaningful".

CONCLUSION

This analysis produced estimates for assessing meaningful within-individual improvements for 8 PRO instruments used in MS studies. These estimates should be useful for interpreting scores and communicating study results and should facilitate decision-making by regulatory and healthcare authorities where these 8 PROs are commonly employed.

Does the Multiple Sclerosis Impact Scale-29 (MSIS-29) have the range to capture the experience of fully ambulatory multiple sclerosis patients? Learnings from the ASCLEPIOS studies

Background

Trials of disease-modifying therapies (DMTs) for multiple sclerosis (MS) often include patients with minimal disability. Patient-reported outcome instruments used in these trials have often not captured physical and psychological treatment effects concomitant with observed clinical benefits.

Objective

To examine whether the Multiple Sclerosis Impact Scale-29 (MSIS-29) captures changes in the impact of MS in a sample of patients enrolled in the Phase 3 ASCLEPIOS studies (ofatumumab vs. teriflunomide).

Methods

Measurement properties (i.e. item fit, reliability, and targeting) of the MSIS-29 were analyzed using Rasch measurement theory (RMT) in data from two phase 3 ofatumumab clinical trials including patients with relapsing-remitting or secondary progressive MS (N = 1882). Targeting of the MSIS-29 items to the patient population was explored within groups categorized by Expanded Disability Status Scale (EDSS) scores.

Results

Under RMT analyses, both the Physical and Psychological Impact scales of the MSIS-29 were not appropriately targeted to the overall sample of patients. In particular, 49% and 30% of patients with an EDSS score ≤ 2.5 had fewer physical and psychological impacts, respectively, than would typically be captured by these MSIS-29 items compared to patients with EDSS scores of ≥ 3.

Conclusion

The MSIS-29 is commonly used to evaluate the patient-reported physical and psychological impact of MS. However, it may be limited in evaluating changes associated with DMTs in patients with minimal disability.

Group cognitive rehabilitation to reduce the psychological impact of multiple sclerosis on quality of life: the CRAMMS RCT

BACKGROUND

People with multiple sclerosis have problems with memory and attention. The effectiveness of cognitive rehabilitation has not been established.

OBJECTIVES

The objectives were to assess the clinical effectiveness and cost-effectiveness of a cognitive rehabilitation programme for people with multiple sclerosis.

DESIGN

This was a multicentre, randomised controlled trial in which participants were randomised in a ratio of 6 : 5 to receive cognitive rehabilitation plus usual care or usual care alone. Participants were assessed at 6 and 12 months after randomisation.

SETTING

The trial was set in hospital neurology clinics and community services.

PARTICIPANTS

Participants were people with multiple sclerosis who had cognitive problems, were aged 18-69 years, could travel to attend group sessions and gave informed consent.

INTERVENTION

The intervention was a group cognitive rehabilitation programme delivered weekly by an assistant psychologist to between four and six participants for 10 weeks.

MAIN OUTCOME MEASURES

The primary outcome was the Multiple Sclerosis Impact Scale - Psychological subscale at 12 months. Secondary outcomes included results from the Everyday Memory Questionnaire, the 30-Item General Health Questionnaire, the EuroQol-5 Dimensions, five-level version and a service use questionnaire from participants, and the Everyday Memory Questionnaire - relative version and the Modified Carer Strain Index from a relative or friend of the participant.

RESULTS

Of the 449 participants randomised, 245 were allocated to cognitive rehabilitation (intervention group) and 204 were allocated to usual care (control group). Of these, 214 in the intervention group and 173 in the control group were included in the primary analysis. There was no clinically important difference in the Multiple Sclerosis Impact Scale - Psychological subscale score between the two groups at the 12-month follow-up (adjusted difference in means -0.6, 95% confidence interval -1.5 to 0.3; p = 0.20). There were no important differences between the groups in relation to cognitive abilities, fatigue, employment, or carer strain at follow-up. However, there were differences, although small, between the groups in the Multiple Sclerosis Impact Scale - Psychological subscale score at 6 months (adjusted difference in means -0.9, 95% confidence interval -1.7 to -0.1; p = 0.03) and in everyday memory on the Everyday Memory Questionnaire as reported by participants at 6 (adjusted difference in means -5.3, 95% confidence interval -8.7 to -1.9) and 12 months (adjusted difference in means -4.4, 95% confidence interval -7.8 to -0.9) and by relatives at 6 (adjusted difference in means -5.4, 95% confidence interval -9.1 to -1.7) and 12 months (adjusted difference in means -5.5, 95% confidence interval -9.6 to -1.5) in favour of the cognitive rehabilitation group. There were also differences in mood on the 30-Item General Health Questionnaire at 6 (adjusted difference in means -3.4, 95% confidence interval -5.9 to -0.8) and 12 months (adjusted difference in means -3.4, 95% confidence interval -6.2 to -0.6) in favour of the cognitive rehabilitation group. A qualitative analysis indicated perceived benefits of the intervention. There was no evidence of a difference in costs (adjusted difference in means -£574.93, 95% confidence interval -£1878.93 to £729.07) or quality-adjusted life-year gain (adjusted difference in means 0.00, 95% confidence interval -0.02 to 0.02). No safety concerns were raised and no deaths were reported.

LIMITATIONS

The trial included a sample of participants who had relatively severe cognitive problems in daily life. The trial was not powered to perform subgroup analyses. Participants could not be blinded to treatment allocation.

CONCLUSIONS

This cognitive rehabilitation programme had no long-term benefits on quality of life for people with multiple sclerosis.

FUTURE WORK

Future research should evaluate the selection of those who may benefit from cognitive rehabilitation.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN09697576.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 4. See the National Institute for Health Research Journals Library website for further project information.

Rasch model of the bridging social capital questionnaire

Bridging social capital is defined as the connections between individuals who are dissimilar with respect to socioeconomic status and other characteristics. We previously identified an important gap in the literature related to its measurement. We developed and validated a scale to measure bridging social capital to be used in Latinx immigrant populations living in the U.S using Classical Test Theory. The structure of the questionnaire comprised the following sub-scales: Socializing in the work place (5 items); Participation in community activities (16 items); Socializing in community activities (5 items); Contact with similar/different people (7 items); Assistance (17 items); Trust of institutions, corporations and other people (14 items); and Trust of intimate people (3 items). Although basic psychometric validation was performed on our original instrument (e.g., content and construct validity, internal consistency reliability), modern testing theory recommends a more comprehensive set of evaluations, including assessment of data quality, scaling assumptions, targeting, reliability, validity and responsiveness. Rasch measurement theory (RMT) is one of the Modern Test Theory methods that assesses the extent to which rigorous measurement is achieved. In the present work, our objective was to further evaluate the instrument using CTT and to use modern psychometric techniques to further validate the questionnaire and create version 2 (v2) using a new sample (N = 224). We developed a Rasch model of the questionnaire to evaluate item fit statistics, item category thresholds, person separation index (PSI), local dependency, differential item functioning (DIF), unidimensionality and targeting and item locations. Assistance was the most problematic sub-scale of all, as item-to-total correlations ranged from 0.27 to 0.66. There were no disordered thresholds on any item, either examined as part of the overall score or as part of sub-scales. However, the analysis provided evidence of the need to modify some of the sub-scales as there was lack of support for unidimensionality or fit to the Rasch model. The Bridging Social Capital Questionnaire v2 has 61 items (compared to 67 in version 1). Our questionnaire may be suitable for adaptation to other immigrant groups in different countries.

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The measurement of bridging social capital is crucial in underserved populations.

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It is crucial to use valid questionnaires to evaluate bridging social capital.

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The use of modern psychometric techniques to evaluate questionnaires is key.

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We present a validated questionnaire using the Rasch model.

A Rasch analysis of the lumbar spine instability questionnaire

Purpose: A 2014 study found that the Lumbar Spine Instability questionnaire predicts response to two different types of exercise therapy. This is the first decision tool that has predicted response to exercise for chronic low back pain. The objective of this study was to evaluate the Lumbar Spine Instability questionnaire using Rasch analysis. Methods: Baseline data from patients included in a randomized controlled trial with chronic non-specific low back pain were included. Rasch Measurement Theory was used to assess the ordering of items along a common scale, data-to-model fit, Person Separation Index, unidimensionality and Differential Item Functioning. Results: Responses from 172 patients (102 females) underwent Rasch analysis. All Lumbar Spine Instability questionnaire items had fit residuals between ± 2.5 and Chi-Square values were non-significant with Bonferroni corrections. The Lumbar Spine Instability questionnaire demonstrated a Person Separation Index of 0.64, which is below the recommended cut-off of 0.7. Differential Item Functioning by different pain levels was identified for one item. Conclusion: The Lumbar Spine Instability questionnaire was found to be unidimensional, suggesting that the use of a summary score is appropriate. However, the low Person Separation Index value suggests that more items may be needed to increase the questionnaire's ability to discriminate among individuals with high and low clinical instability.