Investigation of the psychometric properties of the inclusion body myositis functional rating scale with rasch analysis

Volumetric muscle composition analysis in sporadic inclusion body myositis using fat-referenced magnetic resonance imaging: Disease pattern, repeatability, and natural progression

INTRODUCTION/AIMS

Fat-referenced magnetic resonance imaging (MRI) has emerged as a promising volumetric technique for measuring muscular volume and fat in neuromuscular disorders, but the experience in inflammatory myopathies remains limited. Therefore, this work aimed at describing how sporadic inclusion body myositis (sIBM) manifests on standardized volumetric fat-referenced MRI muscle measurements, including within-scanner repeatability, natural progression rate, and relationship to clinical parameters.

METHODS

Ten sIBM patients underwent whole-leg Dixon MRI at baseline (test-retest) and after 12 months. The lean muscle volume (LMV), muscle fat fraction (MFF), and muscle fat infiltration (MFI) of the quadriceps, hamstrings, adductors, medial gastrocnemius, and tibialis anterior were computed. Clinical assessments of IBM Functional Rating Scale (IBMFRS) and knee extension strength were also performed. The baseline test-retest MRI measurements were used to estimate the within-subject standard deviation (sw). 12-month changes were derived for all parameters.

RESULTS

The MRI measurements showed high repeatability in all muscles; sw ranged from 2.7 to 18.0 mL for LMV, 0.7-1.3 percentage points (pp) for MFF, and 0.2-0.7 pp for MFI. Over 12 months, average LMV decreased by 7.4% while MFF and MFI increased by 3.8 pp and 1.8 pp, respectively. Mean IBMFRS decreased by 2.4 and mean knee extension strength decreased by 32.8 N.

DISCUSSION

The MRI measurements showed high repeatability and 12-month changes consistent with muscle atrophy and fat replacement as well as a decrease in both muscle strength and IBMFRS. Our findings suggest that fat-referenced MRI measurements are suitable for assessing disease progression and treatment response in inflammatory myopathies.

Measurement properties of the Inclusion Body Myositis Functional Rating Scale

OBJECTIVES

To evaluate the validity, reliability, responsiveness and meaningful change threshold of the Inclusion Body Myositis (IBM) Functional Rating Scale (FRS).

METHODS

Data from a large 20-month multicentre, randomised, double-blind, placebo-controlled trial in IBM were used. Convergent validity was tested using Spearman correlation with other health outcomes. Discriminant (known groups) validity was assessed using standardised effect sizes (SES). Internal consistency was tested using Cronbach's alpha. Intrarater reliability in stable patients and equivalence of face-to-face and telephone administration were tested using intraclass correlation coefficients (ICCs) and Bland-Altman plots. Responsiveness was assessed using standardised response mean (SRM). A receiver operator characteristic (ROC) curve anchor-based approach was used to determine clinically meaningful IBMFRS change.

RESULTS

Among the 150 patients, mean (SD) IBMFRS total score was 27.4 (4.6). Convergent validity was supported by medium to large correlations (rs modulus: 0.42-0.79) and discriminant validity by moderate to large group differences (SES=0.51-1.59). Internal consistency was adequate (overall Cronbach's alpha: 0.79). Test-retest reliability (ICCs=0.84-0.87) and reliability of telephone versus face-to-face administration (ICCs=0.93-0.95) were excellent, with Bland-Altman plots showing good agreement. Responsiveness in the worsened group defined by various external constructs was large at both 12 (SRM=-0.76 to -1.49) and 20 months (SRM=-1.12 to -1.57). In ROC curve analysis, a drop in at least two IBMFRS total score points was shown to represent a meaningful decline.

CONCLUSIONS

When administered by trained raters, the IBMFRS is a reliable, valid and responsive tool that can be used to evaluate the impact of IBM and its treatment on physical function, with a 2-point reduction representing meaningful decline.

TRIAL REGISTRATION NUMBER

NCT02753530.

Compound muscle action potential of whole-forearm flexors: A clinical biomarker for inclusion body myositis

Objective

This study aimed to investigate the potential of whole-forearm flexor muscle (WFFM) compound muscle action potential (CMAP) as a quantitative biomarker for inclusion body myositis (IBM) pathology.

Methods

We prospectively enrolled 14 consecutive patients (10 men and 4 women) diagnosed with IBM based on muscle biopsies. We evaluated the baseline-to-peak amplitude of the WFFM CMAP and other quantitative parameters, including grip and pinch strength, Inclusion Body Myositis Functional Rating Scale (IBMFRS) score, and other routine muscle CMAP amplitudes.

Results

The WFFM CMAP was strongly correlated with disease duration and the IBMFRS score. The WFFM CMAP on the more affected side was lower than that on the less affected side. Furthermore, grip power was strongly correlated with the WFFM CMAP, whereas lateral pinch strength was strongly correlated with the WFFM and first dorsal interosseous CMAPs. The 3-point pinch strength was also correlated with the WFFM CMAP.

Conclusions

This study demonstrates that the WFFM CMAP may serve as a biomarker of severity in IBM.

Significance

Identification of this biomarker can support drug development, diagnosis, prognosis, and treatment options for patients with IBM.

Update on the evaluation and management of dysphagia in sporadic inclusion body myositis

PURPOSE OF REVIEW

Dysphagia is a common symptom of sporadic inclusion body myositis (IBM), affecting disease trajectory and patient quality-of-life. Despite this, it is considerably understudied. The purpose of this review is to summarize current evidence related to the evaluation and management of dysphagia in IBM. We highlight a patient case involving a multidisciplinary management approach, and we encourage continued exploration of exercises for delaying progression and improving impairments in patients with IBM and dysphagia.

RECENT FINDINGS

Recent investigations confirm that dysphagia in IBM is a debilitating and complex symptom that warrants timely evaluation and management. Further, they highlight the lack of validation of standardized swallowing-related metrics specifically for IBM and the limited evidence supporting a consensus of management approaches. Small scale research and clinical anecdotal data support a multidisciplinary and multipronged patient-centered approach, including rehabilitative exercise protocols, for dysphagia management in IBM.

SUMMARY

A paucity exists in the literature to effectively guide clinical decision-making for patients with IBM and dysphagia. Given this, it is our belief that a careful multidisciplinary and multipronged patient-centered approach is critical for dysphagia management in IBM. Prospective, longitudinal research on the underlying mechanisms of swallowing dysfunction using advanced and validated swallowing-related outcome measures is urgently needed.

Safety and efficacy of arimoclomol for inclusion body myositis: a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Inclusion body myositis is the most common progressive muscle wasting disease in people older than 50 years, with no effective drug treatment. Arimoclomol is an oral co-inducer of the cellular heat shock response that was safe and well-tolerated in a pilot study of inclusion body myositis, reduced key pathological markers of inclusion body myositis in two in-vitro models representing degenerative and inflammatory components of this disease, and improved disease pathology and muscle function in mutant valosin-containing protein mice. In the current study, we aimed to assess the safety, tolerability, and efficacy of arimoclomol in people with inclusion body myositis.

METHODS

This multicentre, randomised, double-blind, placebo-controlled study enrolled adults in specialist neuromuscular centres in the USA (11 centres) and UK (one centre). Eligible participants had a diagnosis of inclusion body myositis fulfilling the European Neuromuscular Centre research diagnostic criteria 2011. Participants were randomised (1:1) to receive either oral arimoclomol 400 mg or matching placebo three times daily (1200 mg/day) for 20 months. The randomisation sequence was computer generated centrally using a permuted block algorithm with randomisation numbers masked to participants and trial staff, including those assessing outcomes. The primary endpoint was the change from baseline to month 20 in the Inclusion Body Myositis Functional Rating Scale (IBMFRS) total score, assessed in all randomly assigned participants, except for those who were randomised in error and did not receive any study medication, and those who did not meet inclusion criteria. Safety analyses included all randomly assigned participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov, number NCT02753530, and is completed.

FINDINGS

Between Aug 16, 2017 and May 22, 2019, 152 participants with inclusion body myositis were randomly assigned to arimoclomol (n=74) or placebo (n=78). One participant was randomised in error (to arimoclomol) but not treated, and another (assigned to placebo) did not meet inclusion criteria. 150 participants (114 [76%] male and 36 [24%] female) were included in the efficacy analyses, 73 in the arimoclomol group and 77 in the placebo group. 126 completed the trial on treatment (56 [77%] and 70 [90%], respectively) and the most common reason for treatment discontinuation was adverse events. At month 20, mean IBMFRS change from baseline was not statistically significantly different between arimoclomol and placebo (-3·26, 95% CI -4·15 to -2·36 in the arimoclomol group vs -2·26, -3·11 to -1·41 in the placebo group; mean difference -0·99 [95% CI -2·23 to 0·24]; p=0·12). Adverse events leading to discontinuation occurred in 13 (18%) of 73 participants in the arimoclomol group and four (5%) of 78 participants in the placebo group. Serious adverse events occurred in 11 (15%) participants in the arimoclomol group and 18 (23%) in the placebo group. Elevated transaminases three times or more of the upper limit of normal occurred in five (7%) participants in the arimoclomol group and one (1%) in the placebo group. Tubulointerstitial nephritis was observed in one (1%) participant in the arimoclomol group and none in the placebo group.

INTERPRETATION

Arimoclomol did not improve efficacy outcomes, relative to placebo, but had an acceptable safety profile in individuals with inclusion body myositis. This is one of the largest trials done in people with inclusion body myositis, providing data on disease progression that might be used for subsequent clinical trial design.

FUNDING

US Food and Drug Administration Office of Orphan Products Development and Orphazyme.

Study to Assess Content Validity and Interrater and Intrarater Reliability of the Inclusion Body Myositis Functional Rating Scale

Background and Objectives

Sporadic inclusion body myositis (IBM) is a rare, muscle-wasting disease that negatively affects health-related quality of life. Although a measure that has been developed to assess the impact of IBM, the IBM Functional Rating Scale (IBMFRS) has limited evidence of content validity or reliability, and what constitutes a meaningful change threshold; this study was conducted to address these gaps.

Methods

Adult patients with a clinical diagnosis of IBM from the United Kingdom and disease area expert health care professionals from the United States and United Kingdom took part in this study. This study consisted of 5 stages including phone interviews (physicians), face-to-face interviews (patients), face-to-face ratings, phone ratings, and ratings of videos using the IBMFRS.

Results

The IBMFRS adequately captures all core functional impacts of IBM, which was corroborated by both patient participants and physicians when debriefing the measure. Physicians and patient participants all thought any change on the measure would be meaningful change for a patient, either improvement or worsening. The quantitative analysis demonstrated good interrater reliability for face-to-face ratings (intraclass correlation coefficient [ICC] >0.7) and for video ratings (ICC >0.9). Intrarater reliability was excellent for face-to-face and video ratings (ICC >0.9). Equivalence between the modes of administration, face-to-face vs phone, was also excellent (ICC >0.9).

Discussion

The IBMFRS is content valid in assessing the key functional impacts of IBM, and any change would be meaningful. It is reliable both within and across raters, and there is equivalence between different modes of administration (face-to-face vs phone).

Longitudinal observational study investigating outcome measures for clinical trials in inclusion body myositis

OBJECTIVE

To describe decline in muscle strength and physical function in patients with sporadic inclusion body myositis (IBM).

METHODS

Manual muscle testing (MMT), quantitative muscle testing (QMT) and disability scoring using the IBM Functional Rating Scale (IBMFRS) were undertaken for 181 patients for up to 7.3 years. The relationship between MMT, QMT and IBMFRS composite scores and time from onset were examined using linear mixed effects models adjusted for gender and age of disease onset. Adaptive LASSO regression analysis was used to identify muscle groups that best predicted the time elapsed from onset. Cox proportional hazards regression was used to evaluate time to use of a mobility aid.

RESULTS

Multilevel modelling of change in percentage MMT, QMT and IBMFRS score over time yielded an average decline of 3.7% (95% CI 3.1% to 4.3%), 3.8% (95% CI 2.7% to 4.9%) and 6.3% (95% CI 5.5% to 7.2%) per year, respectively. The decline, however, was not linear, with steeper decline in the initial years. Older age of onset was associated with a more rapid IBMFRS decline (p=0.007), but did not influence the rate of MMT/QMT decline. Combination of selected muscle groups allowed for generation of single measures of patient progress (MMT and QMT factors). Median (IQR) time to using a mobility aid was 5.4 (3.6-9.2) years, significantly affected by greater age of onset (HR 1.06, 95% CI 1.04 to 1.09, p<0.001).

CONCLUSION

This prospective observational study represents the largest IBM cohort to date. Measures of patient progress evaluated in this study accurately predict disease progression in a reliable and useful way to be used in trial design.

In Pursuit of an Effective Treatment: the Past, Present and Future of Clinical Trials in Inclusion Body Myositis

Purpose of review

No clinical trial in sporadic inclusion body myositis (IBM) thus far has shown a clear and sustained therapeutic effect. We review previous trial methodology, explore why results have not translated into clinical practice, and suggest improvements for future IBM trials.

Recent findings

Early trials primarily assessed immunosuppressive medications, with no significant clinical responses observed. Many of these studies had methodological issues, including small participant numbers, nonspecific diagnostic criteria, short treatment and/or assessment periods and insensitive outcome measures. Most recent IBM trials have instead focused on nonimmunosuppressive therapies, but there is mounting evidence supporting a primary autoimmune aetiology, including the discovery of immunosuppression-resistant clones of cytotoxic T cells and anti-CN-1A autoantibodies which could potentially be used to stratify patients into different cohorts. The latest trials have had mixed results. For example, bimagrumab, a myostatin blocker, did not affect the 6-min timed walk distance, whereas sirolimus, a promotor of autophagy, did. Larger studies are planned to evaluate the efficacy of sirolimus and arimoclomol.

Summary

Thus far, no treatment for IBM has demonstrated a definite therapeutic effect, and effective treatment options in clinical practice are lacking. Trial design and ineffective therapies are likely to have contributed to these failures. Identification of potential therapeutic targets should be followed by future studies using a stratified approach and sensitive and relevant outcome measures.

Optimizing hand-function patient outcome measures for inclusion body myositis

Inclusion body myositis is the most commonly acquired myopathy after the age of 45. The slowly progressive and heterogeneous disorder is a challenge for measuring clinical trial efficacy. One current method for measuring progression utilizes the Inclusion Body Myositis-Functional Rating Scale. We have found that the upper extremity domain scores in the Inclusion Body Myositis-Functional Rating Scale do not consistently change until there is extreme loss of grip and finger flexor strength. Therefore, we performed a cross-sectional observational study of 83 inclusion body myositis patients and 38 controls recruited at the 2019 Annual Patient Conference of The Myositis Association. We evaluated new Inclusion Body Myositis Patient-Reported Outcome measures for upper extremity function modified from the NIH Patient-Reported Outcomes Measurement Information System as well as pinch and grip strength. We found that Patient-Reported Outcome measures hand-function have a higher correlation with pinch and grip strength than the Inclusion Body Myositis-Functional Rating Scale.

A cross-sectional study of hand function in inclusion body myositis: Implications for functional rating scale

Inclusion body myositis (IBM) is a slowly progressive and heterogeneous disorder that is a challenge for measuring clinical trial efficacy. The current methods of measuring progression of the disease utilizes the Inclusion Body Myositis Functional Rating Scale, grip strength by dynamometer, and finger flexor strength. One of the hallmarks of the disease is selective deep finger flexor weakness. To date, no adequate data has been available to determine how well the Functional Rating Scale relates to this hallmark physical exam deficit. Our study is the first to investigate the degree of correlation between items pertaining to hand function in the Functional Rating Scale with measured grip and finger flexor strength in IBM patients. We have found a lower than expected correlation with finger flexor strength and even lower with grip strength. The current Functional Rating Scale will benefit from optimization to measure clinical progression more accurately.