Posters Characterize DMD Caregiver Experiences, Impact of Gene Therapy on Caregiving Demands

In posters presented at the ISPOR—The Professional Society for Health Economics and Outcomes Research meeting held in Atlanta, Georgia, researchers explored Duchenne muscular dystrophy (DMD) caregiver experiences through cross-sectional surveys,^1,2 and an economic analysis examined gene therapy’s impact on work opportunities for caregivers.³

DMD is an inherited neuromuscular disorder that leads to progressive muscle degeneration and weakness.⁴ It primarily affects boys, and symptom onset is typically in early childhood. Life expectancy for those with DMD has increased in recent years, and survival into the early 30s is becoming more common.

“As DMD progresses, affected individuals rely more heavily on their caregivers,” the authors of one poster wrote.¹ Their cross-sectional survey aimed to characterize the experiences of caregivers in the US, as contemporary data are lacking.

The analysis included 106 US-based caregivers who completed an online survey between March and May 2023. The survey included questions capturing the use of formal (paid) and informal (unpaid) care; informal burden on caregivers rated on a scale from 0 to 10, 10 being the most challenging; and how accessibility barriers impact family plans. The survey results were stratified by patient ambulatory status.

The mean caregiver age was 46 years, and the mean care recipient age was 14.5 years. Eighty-one percent of the caregivers were mothers, and 11% were caregivers for 2 individuals with DMD. Out of 118 total patients with DMD being cared for, 47% (n = 55) were nonambulatory. Caregivers of ambulatory patients reported spending a median of 4.5 hours per day caregiving, while caregivers of nonambulatory patients reported a median of 8 hours per day. The median amount of time spent giving care per day in the overall cohort was 6 hours per day.

Caregivers reported a median burden of 5 overall, with those caring for nonambulatory patients reporting a burden of 6 and caregivers of ambulatory recipients reporting a burden rating of 4. Overall, 75% of caregivers reported utilizing additional informal caregiving, and 26% used additional formal caregiving. Of those using formal caregiving, 13% were caregivers for ambulatory patients and 42% were caregivers for nonambulatory patients. Accessibility barriers led to frequent changes in everyday plans for 74% of families.

Overall, the findings show the significant amounts of time and energy required of caregivers for individuals with DMD, as well as the increasing demands associated with disease progression.

Muscular dystrophy | Image credit: Lemau Studio - stockadobe.com

Another poster highlighted the impacts of caregiving on paid work, including the extent of DMD caregivers’ paid work accommodations and lost productivity based on survey results.² The investigators recruited survey participants through a US-based DMD advocacy group and included questions from the Work Productivity and Activity Impairment (WPAI) questionnaire for DMD caregivers, with higher scores indicating greater impairment.

Among 106 caregivers, 81% were mothers, and the mean age was 46, and 89% of caregivers reported caring for 1 individual with DMD. The annual household income was greater than $100,000 annually for 49% of households in the study.

Overall, 68% of respondents (n = 72) were employed, with 55% (n = 52) employed full-time. Based on WPAI scores, 40.7% of respondents had experienced overall activity impairment in the past week, and absenteeism among those employed was 8.4%. Presenteeism, or impairment at work, was reported by 30.5% of caregivers, and absenteeism plus presenteeism (work productivity loss) by 34.8%. Among the 11% of caregivers caring for 2 individuals with DMD, 67% (n = 8) were employed, and 62.5% (n = 5) reported work productivity was impacted by DMD.

Furthermore, 77% (n = 82) of caregivers reported work-related changes due to caregiving responsibilities. Twenty-five percent quit, 26% took lower paying jobs, 34% changed their job role or responsibilities, 29% reduced working hours, and 34% took time off from work.

“The results demonstrate the considerable paid work impact associated with caregiving for one or two individuals with DMD,” the authors concluded, noting that the findings are limited due to the low number of caregivers of 2 individuals included in the study.

In an economic analysis, investigators explored how delandistrogene moxeparvovec (Elevidys; Sarepta Therapeutics), a gene therapy approved for the treatment of ambulatory patients aged 4 to 5 years with DMD, could impact the work opportunity of those caring for patients with DMD.³ They developed a partitioned survival model including 5 states—early ambulatory, late ambulatory, early nonambulatory, late nonambulatory, and death—and estimated outcomes and caregiver work opportunity with standard-of-care (SOC) treatment vs SOC plus gene therapy for a cohort of 4-year-old early ambulatory patients with DMD. The researchers applied 2.8% salary growth and 3% discount rates annually.

With SOC treatment alone, caregivers were estimated to lose 7194 (15.5%) hours and experience a lifetime income loss of $249,697 (16.1%)/undiscounted $431,911 (16.2%) compared with the general US population. Caregivers of patients treated with SOC plus gene therapy were estimated to lose 4564 (9.8%) hours, equating a lifetime income loss of $153,396 (9.9%)/undiscounted $318,375 (11.9%) compared with the general population.

“DMD substantially impacts caregiver work opportunity and income,” the authors concluded. “Based on this model, delandistrogene moxeparvovec could potentially increase caregiver work opportunity.”

Reference

1. Audhya IF, Dunne JS, Patel S, et al. Characterizing the experience of caregiving for those with Duchenne muscular dystrophy (DMD): results from a cross-sectional survey. Presented at: International Society for Pharmacoeconomics and Outcomes Research 2024; May 5-8, 2024; Atlanta, GA. Poster 6044.

2. Patel S, Dunne JS, Audhya IF, et al. The balancing act of paid work and caregiving in Duchenne muscular dystrophy (DMD): results from a cross-sectional survey. Presented at: International Society for Pharmacoeconomics and Outcomes Research 2024; May 5-8, 2024; Atlanta, GA. Poster 6018.

3. Innis B, Henry A, Nelson L, et al. Economic analysis of the impact of delandistrogene moxeparvovec gene therapy on work opportunity in caregivers of individuals with Duchenne muscular dystrophy. Presented at: International Society for Pharmacoeconomics and Outcomes Research 2024; May 5-8, 2024; Atlanta, GA. Poster 2050.

4. Duchenne muscular dystrophy (DMD). Muscular Dystrophy Association. Accessed May 9, 2024. https://www.mda.org/disease/duchenne-muscular-dystrophy