Measuring Duchenne muscular dystrophy impact: development of a proxy-reported measure derived from PROMIS item banks

When better is the enemy of good: two cautionary tales of conceptual validity versus parsimony in clinical psychometric research

This paper presents an empirical challenge to the assumption that an item-response theory analysis always yields a better measure of a clinical construct. We summarize results from two measurement development studies that showed that such an analysis lost important content reflecting the conceptual model ("conceptual validity"). The cost of parsimony may thus be too high. Conceptual models that form the foundation of QOL measurement reflect the patient's experience. This experience may include concepts and items that are psychometrically "redundant" but capture distinct features of the concept. Good measurement is likely a balance between relying on IRT's quantitative metrics and recognizing the importance of conceptual validity and clinical utility.

Exploring the Dynamics of Caring for a Child With a Terminal Illness of Duchenne Muscular Dystrophy (DMD) and Its Copious Components on the Caregivers

Duchenne muscular dystrophy (DMD) is an inherited disorder that results in increasing muscle degeneration and muscle weakness because of a mutation in the dystrophin protein. Despite there being no cure for this condition, early diagnosis can slow down the progression of muscle weakness. Studies have shown that families and caregivers of patients with DMD have limited access to support systems, further intensifying their responsibilities. Since the mental well-being of families and caregivers of patients with DMD is crucial for healthy and progressive family dynamics, ascertaining the psychological and social impacts it has on the caregivers will help improve the quality of life of patients with this terminal illness. This study aims to recognize the direct and indirect effects on the caregiver caring for the individual diagnosed with DMD, with a primary focus on the health-related quality of life (HRQoL), psychological well-being, and financial burden. Using the PubMed database and a particular arrangement of Medical Subject Headings (MeSH) terms, 93 articles were retrieved and evaluated, of which eight only met the inclusion criteria. The eight chosen articles were organized into a table and dissected further for their importance and relevance to this review article. This literature review highlights the most significant information from each article and is individually analyzed to deduce the main burdens on caregivers of patients with the terminal illness of DMD.  Conclusively, this review highlights that caregivers of individuals with DMD bear a substantial burden that negatively affects their HRQoL, contributes to a decline in psychological well-being, and places an increased financial burden on the family.

Interplay of disability, caregiver impact, and out-of-pocket expenditures in Duchenne muscular dystrophy: a cohort study

Background

Providing caregiving support to people with Duchenne muscular dystrophy (DMD) is challenging, beginning in early childhood, and continuing through the progression of multidimensional disability. This study addressed the interplay between caregiver impact, out-of-pocket expenditures, and DMD disability. To examine these interconnections, we investigated the association between caregiver impact domains and out-of-pocket expenditures; and the presence of clusters in caregivers on the basis of DMD-related disability domains in the patients for whom they provided caregiving support.

Methods

This web-based study recruited 566 DMD caregivers (140 males, 426 females; mean age 41.6 years, SD 8.8, range 21–72), examining caregiver impact using the DMD Caregiver Impact Measure, PROMIS-derived parent-proxy (PPP) measures of their child’s disability, and items tapping out-of-pocket expenditures related to home and vehicle accommodations and assistive devices. T-tests compared caregiver impact scores by out-of-pocket expenditures incurred. Latent Profile Analyses (LPA) were conducted to generate impact profiles related to child’s disability as reported by caregiver proxies.

Results

Higher out-of-pocket expenditures were generally associated with worse impact on the subscales, but several expenditures (e.g., kitchen, bathroom, scooter) were associated with lower impact. LPA indicated that the four-group solution provided the best relative fit and yielded good profile separation (entropy = 0.91). Caregivers with lowest impact reported the highest mobility, cognitive, and upper extremity functioning of their DMD care recipients, whereas the highest caregiver impact was driven by their care recipient’s negative affect and fatigue. The upper-middle impact group showed great variability in proxy-disability domains, whereas the lower-middle group had similar levels of disability across domains. Profiles were represented across all child ages.

Conclusion

Out-of-pocket expenditures were often associated with worse caregiver impact, but some associated with milder impact (i.e., bathroom or kitchen modification, investing in a ceiling lift or medical scooter). While their son’s level of disability and age were related to impact on the DMD caregiver, the domains giving rise to highest caregiver impact were not the most visible aspects of disability, such as mobility, but rather negative affect and fatigue. Other contextual attributes are likely implicated, and will be addressed in the companion paper.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-022-00425-2.