Comparative responsiveness of the health utilities index and the RAND-12 for multiple sclerosis

Physical and Mental Health-Related Quality of Life Trajectories Among People With Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Most studies of health-related quality of life (HRQoL) in multiple sclerosis (MS) have been cross-sectional. The few longitudinal studies have not accounted for potential heterogeneity in HRQOL trajectories. There may be groups of individuals with common physical or mental HRQoL trajectories over time. Identification of early risk factors for membership in trajectories with poor HRQoL would inform on those at risk. We aimed to identify physical and mental HRQoL trajectories among people with MS and early risk factors for membership in the trajectory groups with the worst HRQoL.

METHODS

Between 2004 and 2020, we queried NARCOMS participants regarding HRQoL using the RAND-12, demographics, fatigue, and physical impairments (using the Patient-Determined Disease Steps scale). We included participants who were enrolled in the NARCOMS registry within 3 years of MS diagnosis, lived in the United States, reported physician-confirmed MS, and had ≥3 HRQoL observations. We used group-based trajectory modeling to determine whether there were distinct clusters of individuals who followed similar HRQoL trajectories over time. We evaluated whether baseline participant characteristics associated with the probability of trajectory group membership using a multinomial logit model.

RESULTS

We included 4,888 participants who completed 57,564 HRQoL questionnaires between 1 and 27 years after MS diagnosis. Participants had a mean (SD) age of 41.7 (9.5) years at diagnosis, and 3,978 participants (81%) were women. We identified 5 distinct physical HRQoL trajectories and 4 distinct mental HRQoL trajectories. Older age at diagnosis, worse physical impairments, and worse fatigue were associated with an increased odds of being in the group with the worst physical HRQoL when compared with being in the other 4 groups. Income ≤$50,000 and no postsecondary education were associated with an increased odds of membership in the group with the lowest mental HRQoL when compared with that in the other 3 groups.

DISCUSSION

We identified groups of people with MS who reported similar physical and mental HRQoL trajectories over time. There are early risk factors for membership in the groups with the worst HRQoL that are easily identifiable by clinicians, providing an opportunity for early interventions.

Characterizing Long-term Disability Progression and Employment in NARCOMS Registry Participants with Multiple Sclerosis Taking Dimethyl Fumarate

Background

Delayed-release dimethyl fumarate (DMF) is effective in relapsing-remitting multiple sclerosis (RRMS), but long-term effects of DMF on disability and disease progression in clinical settings are unknown. We evaluated disability and employment outcomes in persons with RRMS treated with DMF for up to 5 years.

Methods

This longitudinal study included US North American Research Committee on Multiple Sclerosis (NARCOMS) Registry participants with RRMS reporting DMF initiation in fall 2013 through spring 2018 with 1 year or more of follow-up. Time to 6-month confirmed disability progression (≥1-point increase in Patient-Determined Disease Steps [PDDS] score) and change in employment status were evaluated using Kaplan-Meier analysis. Participants were censored at last follow-up or at DMF discontinuation, whichever came first.

Results

During the study, 725 US participants with RRMS had at least 1 year of DMF follow-up data, of whom most were female and White. At year 5, 69.9% (95% CI, 65.4%-73.9%) of these participants were free from 6-month confirmed disability progression, and 84.7% (95% CI, 78.6%-89.2%) were free from conversion to secondary progressive MS. Of 116 participants with data at baseline and year 5, most had stable or improved PDDS and Performance Scales scores over 5 years. Of 322 participants 62 years and younger and employed at the index survey, 66.0% (95% CI, 57.6%-73.1%) were free from a negative change in employment type over 5 years.

Conclusions

Most US NARCOMS Registry participants treated up to 5 years with DMF remained free from 6-month confirmed disability progression and conversion to secondary progressive MS and had stable disability and employment status. These results support the long-term stability of disability and work-related outcomes with disease-modifying therapy.

Comparing the MSIS-29 and the Health Utilities Index Mark III in Multiple Sclerosis

Objective: Since the properties of health-related quality of life measures vary across samples, studies directly comparing the properties of different measures can be useful in understanding their relative strengths and limitations. We aimed to compare the psychometric properties of the Health Utilities Index Mark III (HUI3) and the Multiple Sclerosis Impact Scale-29 (MSIS-29).

Methods: In Spring 2020, North American Research Committee on Multiple Sclerosis (NARCOMS) Registry participants completed the HUI3, MSIS-29, Patient Determined Disease Steps (PDDS) and SymptoMScreen. For the HUI3 and MSIS-29 we assessed floor and ceiling effects, construct validity, and internal consistency reliability. We used relative efficiency to compare the discriminating ability of the two measures with respect to disability.

Results: We included 5,664 participants in the analysis, with mean (SD) age 63 (10.1) years; 4,579 (80.8%) were women. For the HUI3 the mean (SD) score was 0.44 (0.32), for the MSIS-29 physical it was 34.0 (24.2) and for the MSIS-29 psychological it was 25.9 (20.4). Neither of the measures had floor or ceiling effects, and internal consistency reliability was > 0.70 for both. The HUI3 and MSIS-29 physical were strongly correlated (r = −0.78; 95%CI:−0.79,−0.77). The correlation between the HUI3 and MSIS-29 psychological was weaker but remained moderately strong (r = −0.64; 95%CI:−0.66,−0.63). After adjusting for sociodemographic and clinical factors, relative efficiency to discriminate between disability (PDDS) groups was highest for the MSIS-29 physical scale, followed by the HUI3.

Conclusion: Both measures had adequate validity and reliability. The MSIS-29 physical discriminated between disability groups better than the HUI3.