Addressing the targeting range of the ABILHAND-56 in relapsing-remitting multiple sclerosis: A mixed methods psychometric study

[Questionnaires for arm function assessment in patients with multiple sclerosis]

Arm dysfunction is one of the disabling manifestations of multiple sclerosis (MS), especially in later stages of the disease. Assessment of the functioning of the upper limbs is necessary to objectify the course of MS, determine the effectiveness of therapy, and individualize rehabilitation measures. The tools that assess the upper extremity dysfunction include tests and questionnaires. Questionnaires (patient-reported outcome measures) represent the special importance, since the opinions and preferences of patients themselves help to implement a patient-centered approach to treatment. The article presents a brief description of three multidimensional MS-specific and four unidimensional MS-nonspecific questionnaires that used in assessment of upper limb function in MS patients. The disease-specific unidimensional Arm Function in Multiple Sclerosis Questionnaire (AMSQ), specifically designed to assess the arm use in patients with MS, is discussed in more detail. The use of AMSQ in the Russian population is possible only after the procedure of cultural adaptation and validation of the Russian version.

Providing meaningful interpretation of performance outcome measures by co-calibration with patient-reported outcomes through the Rasch model: illustration with multiple sclerosis measures

Performance outcome (PerfO) measures are based on tasks performed by patients in a controlled environment, making their meaningful interpretation challenging to establish. Co-calibrating PerfO and patient-reported outcome (PRO) measures of the same target concept allow for interpretation of the PerfO with the item content of the PRO. The Rasch model applied to the discretized PerfO measure together with the PRO items allows expressing parameters related to the PerfO measure in the PRO metric for it to be linked to the PRO responses. We applied this approach to two PerfO measures used in multiple sclerosis (MS) for walking and manual ability: the Timed 25-Foot Walk (T25FW) and the 9-Hole Peg Test (9HPT). To determine meaningful interpretation of these two PerfO measures, they were co-calibrated with two PRO measures of closely related concepts, the MS walking scale - 12 items (MSWS-12) and the ABILHAND, using the data of 2,043 subjects from five global clinical trials in MS. The probabilistic relationships between the PerfO measures and the PRO metrics were used to express the response pattern to the PRO items as a function of the unit of the PerfOs. This example illustrates the promises of the co-calibration approach for the interpretation of PerfO measures but also highlights the challenges associated with it, mostly related to the quality of the PRO metric in terms of coverage of the targeted concept. Co-calibration with PRO measures could also be an adequate solution for interpretation of digital sensor measures whose meaningfulness is also often questioned.

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.

Applying a mixed methods design to test saturation for qualitative data in health outcomes research

Saturation, a core concept in qualitative research, suggests when data collection might end. It is reached when no new relevant information emerges with additional interviews. The aim of this research was to explore whether a mixed methods design could contribute to the demonstration of saturation. Firstly, saturation was conceptualized mathematically using set theory. Secondly, a conversion mixed design was conducted: a set of codes derived from qualitative interviews were quantitized and analyzed using partial least squares (PLS) regression to document whether saturation was reached. A qualitative study conducted by other researchers prior to this work (i.e. none of the present authors was involved in this study) was used to test saturation using PLS regression. This illustrative qualitative study aimed to investigate the impact of Clostridium difficile infection (CDI) on nurses' work in the hospital and the results were published elsewhere (Guillemin et al. 2015). Semi-structured interviews were conducted with 12 nurses. Saturation was characterized by the cumulative percentage of variability accounted for by PLS factors. After 12 interviews, this percentage was 51% which suggests that saturation was achieved at least on main themes. Two main themes identifying similarities in the experience of nurses caring for patients with CDI were identified: Organization/Coordination of the working day and Time-consuming work. Although dependent on the coding of qualitative data, PLS regression of quantitized data from qualitative interviews generated useful information for the determination of saturation.

Differential item functioning of the Arm function in Multiple Sclerosis Questionnaire (AMSQ) by language, a study in six countries

BACKGROUND

The Arm function in Multiple Sclerosis Questionnaire (AMSQ) has been developed as a self-reported measure of arm and hand functioning for patients with multiple sclerosis (MS). The AMSQ was originally developed in Dutch and to date translated into five languages (i.e. English, German, Spanish, French, and Italian).

OBJECTIVE

The aim of this study was to evaluate differential item functioning (DIF) of the AMSQ in these languages.

METHODS

We performed DIF analyses, using "language" as the polytomous group variable. To detect DIF, logistic regression and item response theory principles were applied. Multiple logistic regression models were evaluated. We used a pseudo R² value of 0.02 or more as the DIF threshold.

RESULTS

A total of 1733 male and female patients with all subtypes of MS were included. The DIF analysis for the whole dataset showed no uniform or non-uniform DIF on any of the 31 items. All R² values were below 0.02.

CONCLUSION

The AMSQ is validated in six languages. All items have the same meaning to MS patients in Dutch, English, German, Spanish, French, and Italian. This validation study enables use of the AMSQ in international studies, for monitoring treatment response and disease progression.