Descriptions of Physical Limitations, Symptoms of DMD From the Patient, Caregiver Perspective

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A recent study published in the Journal of Patient-Reported Outcomes, provided greater insight into the caregiver and patient perspective of living with Duchenne muscular dystrophy (DMD), particularly regarding physical limitations and symptom burden.

The results fill in knowledge gaps about how DMD impacts ambulatory and non-ambulatory patients and can help inform patient-centered strategies for assessing clinical outcomes in future DMD research. Previous qualitative studies have primarily focused on non-ambulatory patients. The present analysis sought to explore the symptoms, overall functioning, and impacts of DMD on daily life, as well as gather information on the desires and expectations for new treatments, including minimal benefits that would have a noticeable impact.

The cross-sectional, qualitative interview study included 46 parent/patient dyads who met the eligibility criteria: male patients aged 4 years or older with a genetically confirmed DMD diagnosis and caregivers who were 18 years or older and the primary caregiver of a patient with DMD.

Trained researchers conducted interviews of the patients/caregiver dyad using a semi-structured interview guide. Individuals with DMD were asked to respond first, and the caregiver was given opportunity to provide additional comments. Open-ended questions were used to explore the patients and caregiver perspectives on the impact DMD had on overall function and daily life. The interviews were audio-recorded and professionally transcribed for analysis.

The majority of caregivers were mothers (87.8%), and 4 caregivers had multiple children with DMD and participated in more than 1 dyad interview. Most caregivers were White (92.7%), had at least some college (95.1%) and were employed at the time of the interview (95.1%). Over half of the patients were classified as ambulatory (n = 28; 60.9%). The average (SD) age of ambulatory patients was 8.7 (3.35) years and the average age of non-ambulatory patients was 11.3 (3.27) years. The average time since diagnosis was 3.7 (2.3) years for all patients.

Both groups consistently reported primary symptoms such as a lack of strength (ambulatory: n = 28, 100.0%; non-ambulatory: n = 17, 94.4%) and fatigue (ambulatory: n = 24, 85.7%; non-ambulatory: n = 14, 77.8%). DMD predominantly affected physical function, with participants noting a progressive decline in physical strength as the defining feature of the disease across all stages of ambulatory ability.

Among ambulatory patients, the ways DMD impacted physical function included impaired mobility, such as when climbing stairs (n = 16; 57.1%) or running (n = 13; 46.4%); compromised upper body function; particularly in fine motor skills, like holding a pen/pencil or buttoning clothes (n = 17, 60.7%); difficulties with transfers, such as getting off the floor (n = 10; 35.7%); and challenges in activities of daily living (ADLs; n = 15, 53.6%).

Non-ambulatory participants frequently described functional impacts such as problems with transfers (eg, getting in/out of bed: n = 13, 72.2%; getting in/out of chair or position in bed: both n = 10, 55.6%), impaired upper body function (reaching: n = 14, 77.8%), and ADLs (n = 15; 83.3%).

Treatment goals varied based on ambulatory status; for ambulatory participants, goals included maintaining current functioning (n = 20; 71.4%), improving muscle strength (n = 7; 25.9%), and reducing fatigue (n = 6; 22.2%). Non-ambulatory participants expressed goals such as increased upper body strength (n = 8; 42.1%) and greater independence in ADLs (n = 6; 31.6%). A preliminary conceptual model was developed to visually represent the primary symptoms and physical function impacts of DMD and their relationship to disease progression.

The study limitations include potential influence due to interviewing the caregiver in the presence of the child, limited sample representation, underrepresentation of participants at more advanced and severe stages of DMD, caution in extrapolating the findings to older non-ambulatory patients, and the lack of differentiation between muscular and systemic fatigue. These limitations should be considered when interpreting the findings and designing future research in this area.

“By including non-ambulatory individuals, we gained a deeper understanding of the symptoms and impacts affecting DMD individuals in later stages of the disease and what they value most compared with individuals who are still ambulatory,” wrote the researchers. "Furthermore, regulatory guidance to approve new therapies, particularly in rare diseases that can present heterogeneously, relies on the patient’s perspective, which feeds into developing patient-reported outcome measures that can help determine what patients and their caregivers consider to be meaningful change."

Reference

Brown V, Merikle E, Johnston K, Gooch K, Audhya I, Lowes L. A qualitative study to understand the Duchenne muscular dystrophy experience from the parent/patient perspective. J Patient Rep Outcomes. 2023;7(1):129. doi:10.1186/s41687-023-00669-6.