The challenges inherent with anchor-based approaches to the interpretation of important change in clinical outcome assessments

Dyspnea (breathlessness) in amyotrophic lateral sclerosis/motor neuron disease: prevalence, progression, severity, and correlates

OBJECTIVE

Dyspnea, or breathlessness, is an important symptom in amyotrophic lateral sclerosis/motor neuron disease (ALS/MND). We examined the measurement properties of the Dyspnea-12.

METHODS

Rasch analysis enabled conversion of raw Dyspnea-12 scores to interval level metric equivalents. Converted data were used to perform trajectory modeling; those following different trajectories were compared for demographic, clinical, symptom, and functioning characteristics. Logistic regression examined differences between distinct trajectories.

RESULTS

In 1022 people, at baseline, mean metric Dyspnea-12 was 7.6 (SD 9.3). 49.8% had dyspnea, severe in 12.6%. Trajectory analysis over 28 months revealed three breathlessness trajectories: group 1 reported none at baseline/follow-up (42.7%); group 2 significantly increased over time (9.4%); group 3 had a much higher level at baseline which rose over follow-up (47.9%). Group 3 had worse outcomes on all symptoms, functioning and quality of life; compared to group 1, their odds of: respiratory onset sixfold greater; King's stage ≥3 2.9 greater; increased odds of being bothered by choking, head drop, fasciculations, and muscle cramps; fatigue and anxiety also elevated (p < .01).

CONCLUSION

Dyspnea is a cardinal symptom in ALS/MND and can be quickly measured using the Dyspnea-12. Raw scores can easily be converted to interval level measurement, for valid change scores and trajectory modeling. Dyspnea trajectories reveal different patterns, showing that clinical services must provide monitoring which is customized to individual patient need. Almost half of this large population had worsening dyspnea, confirming the importance of respiratory monitoring and interventions being integrated into routine ALS care.

Responsiveness and Minimal Clinically Important Difference of the Canadian Occupational Performance Measure Among Patients With Frozen Shoulder

IMPORTANCE

Patient-reported outcome measures provide insights into intervention effects on patients. The Canadian Occupational Performance Measure (COPM) emphasizes identifying priorities in daily activity engagement and evaluating an individual's perception of changes over time.

OBJECTIVE

To assess the responsiveness of the COPM and the minimal clinically important difference (MCID) among patients with frozen shoulders.

DESIGN

Prospective, single-blind, randomized controlled trial.

SETTING

Two physical medicine and rehabilitation clinics.

PARTICIPANTS

Ninety-four patients with frozen shoulders enrolled in a previous study.

OUTCOMES AND MEASURES

Baseline and 3-mo evaluations of the COPM and other measures. Responsiveness was assessed using effect size (ES) and standardized response mean (SRM). The MCID values were determined through a distribution-based approach, which used the 0.5 standard deviation and ES methods, and an anchor-based approach, which used the receiver operating characteristic curve method.

RESULTS

The ES and SRM results indicated that the COPM had high responsiveness. The distribution-based MCID values for COPM Performance and COPM Satisfaction were 1.17 and 1.44, respectively. The anchor-based MCID values were 2.5 (area under the curve [AUC] = 0.78, 95% confidence interval [CI] [0.64-0.91]) and 2.1 (AUC = 0.76, 95% CI [0.60-0.91]), respectively.

CONCLUSIONS AND RELEVANCE

The findings suggest that the COPM is a responsive outcome measure for patients with frozen shoulder. The established MCID values for the COPM can be valuable for interpreting changes in patient performance and satisfaction, thus aiding clinical interventions and research planning. Plain-Language Summary: This is the first study to review the effectiveness of the Canadian Occupational Performance Measure (COPM) to determine the success of occupational therapy interventions for people with a frozen shoulder. The findings suggest that the COPM is an effective and valuable tool for clients with a frozen shoulder to understand their experiences and treatment priorities and to detect meaningful changes in their performance and satisfaction after an occupational therapy intervention.

Clinical meaningfulness and psychometric robustness of the MG Symptoms PRO scales in clinical trials in adults with myasthenia gravis

Objectives

The objective of this research was to generate psychometric evidence supporting the myasthenia gravis (MG) symptoms patient-reported outcome (PRO) scales as a fit-for-purpose measure of severity of core symptoms of MG and provide information allowing their meaningful interpretation using data from a phase 3 study in MG.

Methods

Data from the MycarinG study, a phase 3 study of rozanolixizumab in patients with generalized MG who experience moderate to severe symptoms (ClinicalTrials.gov Identifier: NCT03971422) were analyzed with both classical test theory (CTT) and Rasch measurement theory (RMT). Meaningful within-individual change and group-level meaningful change were estimated for three MG Symptoms PRO scales using anchor- and distribution-based methods. Anchor-based methods used patient global impression of severity (PGIS) and change (PGIC) in MG symptoms as anchors.

Results

Good measurement properties of the MG Symptoms PRO scales were shown in the sample of 200 participants: good to excellent reliability (test-retest and internal consistency reliability) and validity (associations between items and scores within the MG Symptoms PRO scales and between the MG Symptoms PRO scores and other clinical outcomes-MG ADL, QMG score, MGC score, and MGFA classes-were as expected); and the items showed good coverage of the continuum and fit to the Rasch model. Triangulation of the anchor- and distribution-based method results led to the definition of clinically meaningful within-patient improvement in scores for Muscle Weakness Fatigability (-16.67), Physical Fatigue (-20.00), and Bulbar Muscle Weakness (-20.00), with associated ranges. Benchmarks are also proposed for the interpretation of group-level results.

Conclusion

The strong psychometric performance of the MG Symptoms PRO scales and the information generated to guide its interpretation supports its use in clinical trials for demonstrating the clinical benefits of new treatments targeting core symptoms of MG (muscle weakness fatigability, physical fatigue, bulbar muscle weakness, respiratory muscle weakness, and ocular muscle weakness).

Anchor-based minimal important difference values are often sensitive to the distribution of the change score

PURPOSE

Anchor-based studies are today the most popular approach to determine a minimal important difference value for an outcome variable. However, a variety of construction methods for such values do exist. This constitutes a challenge to the field. In order to distinguish between more or less adequate construction methods, meaningful minimal requirements can be helpful. For example, minimal important difference values should not reflect the intervention(s) the patients are exposed to in the study used for construction, as they should later allow to compare interventions. This requires that they are not sensitive to the distribution of the change score observed. This study aims at investigating to which degree established construction methods fulfil this minimal requirement.

METHODS

Six constructions methods were considered, covering very popular and recently suggested methods. The sensitivity of MID values to the distribution of the change score was investigated in a simulation study for these six construction methods.

RESULTS

Five out of six construction methods turned out to yield MID values which are sensitive to the distribution of the change score to a degree that questions their usefulness. Insensitivity can be obtained by using construction methods based solely on an estimate of the conditional distribution of the anchor variable given the change score.

CONCLUSION

In future the computation of MID values should be based on construction methods avoiding sensitivity to the distribution of the change score.

Meaning of Family Reported Outcome Measure (FROM-16) severity score bands: a cross-sectional online study in the UK

OBJECTIVE

To assign clinical meanings to the Family Reported Outcome Measure (FROM-16) scores through the development of score bands using the anchor-based approach.

DESIGN AND SETTING

A cross-sectional online study recruited participants through UK-based patient support groups, research support platforms (HealthWise Wales, Autism Research Centre-Cambridge University database, Join Dementia Research) and through social service departments in Wales.

PARTICIPANTS

Family members/partners (aged ≥18 years) of patients with different health conditions.

INTERVENTION

Family members/partners of patients completed the FROM-16 questionnaire and a Global Question (GQ).

MAIN OUTCOME MEASURE

Various FROM-16 band sets were devised as a result of mapping of mean, median and mode of the GQ scores to FROM-16 total score, and receiver operating characteristic-area under the curve cut-off values. The band set with the best agreement with GQ based on weighted kappa was selected.

RESULTS

A total of 4413 family members/partners (male=1533, 34.7%; female=2858, 64.8%; Prefer not to say=16, 0.4%; other=6, 0.14%) of people with a health condition (male=1994, 45.2%; female=2400, 54.4%; Prefer not to say=12, 0.3%; other=7, 0.16%) completed the online survey: mean FROM-16 score=15.02 (range 0-32, SD=8.08), mean GQ score=2.32 (range 0-4, SD=1.08). The proposed FROM-16 score bandings are: 0-1=no effect on the quality of life of family member; 2-8=small effect on family member; 9-16=moderate effect on family member; 17-25=very large effect on family member; 26-32=extremely large effect on family member (weighted kappa=0.60).

CONCLUSION

The FROM-16 score descriptor bands provide new information to clinicians about interpreting scores and score changes, allowing better-informed treatment decisions for patients and their families. The score banding of FROM-16, along with a short administration time, demonstrates its potential to support holistic clinical practice.