Multiple studies have been published on the caregiver burden associated with geriatric illnesses (e.g. Alzheimer’s Disease, Parkinson’s Disease), however there is limited data available on disease impact of chronic pediatric diseases on caregiver HRQoL [20, 21]. Parents, who become caregivers, may confront more challenges than those caring for geriatric patients primarily as their role is rarely voluntary . The findings of this survey suggest that SMA has a substantial impact on caregivers’ daily activities as well as their HRQoL. The vast majority of the caregivers in this study were parents who reported their patients were receiving treatment with nusinersen. In the primary study of this survey the majority of these caregivers reported they were either ‘very’ or ‘extremely satisfied’ with the current DMT . While patients with type 1 SMA now have improved survival and caregivers overall valued the advancement in the treatment landscape, there continues to be a large time expenditure required in managing the treatment and care for their SMA patients. The time burden may be attributed to multiple factors such as caregivers working with insurance providers and managing treatment related details such as driving to a treatment center. Treatment management may consume some portion of a caregiver’s time; however, other elements such as equipment management, occupational and physical therapy, positioning, and transferring likely contribute to the majority of the time spent on managing care. The Voice of the Patient Report from Cure SMA, details the challenges caregivers and patients face with regard to burden and the impact on their daily lives .
Importantly, this study suggests that a more severe disease status, as measured by SMA type or patient motor function, was also associated with more time spent managing patient care and lower overall HRQoL for the caregivers. Caregivers of patients with type 1 SMA spent on average an additional 13 hours per month managing the care of their patients compared with caregivers of patients with type 2/3 SMA. Similarly, caregivers of patients with minimal function reported spending an average of 63 additional hours every month caregiving compared with caregivers of SMA patients who could stand or walk. Although we surveyed a very heterogeneous caregiver population, our study shows a directional trend with regard to caregiver HRQoL, patient phenotype, and motor function ability.
It is difficult to compare these results with other chronic childhood illnesses given the progressive and debilitating nature of SMA. While not fully analogous, Duchenne muscular dystrophy is also a rare neuromuscular pediatric condition with considerable caregiving needs. Landfeldt et al. found a mean EQ-5D ranged between 0.85 − 0.77 across ambulatory groups and 0.88 − 0.57 across caregivers’ rating of the child’s health and mental status . In our study, the EQ-5D utility scores reported for caregivers of type 1 SMA patients (0.61 ± 0.28) were markedly lower than for those of type 2/3 SMA patients (0.76 ± 0.27), suggesting the additional onus felt by caregivers in tending to patients with more severe disease. Similarly, caregivers of patients who could stand or walk reported utility scores that were near 1 (perfect health) compared with those caring for patients with minimal motor function. Moreover, while the overall HRQoL score for SMA caregivers was similar to the US population average, the percentage of caregivers reporting any problem was higher in 3 dimensions [Figure 4] . While it is difficult to establish a rationale for the caregivers who reported an inability to walk or perform activities of daily living, it is plausible that caregivers may have potentially misinterpreted the question, these caregivers may have a milder type of SMA themselves, or that the caregiving burden prevents them from caring for themselves.
The EQ-5D-5L methodology employed in this study has been utilized in other studies assessing caregiver outcomes in SMA . López-Bastida et al. noted a reduced HRQoL (utility score = 0.49) in caregivers of SMA patients from a Spanish population, showing a stronger deterioration in HRQoL relative to our study . The study also similarly reported caregivers spent around 8 hours per day providing care to the children owing to limitations caused by SMA. A Dutch study utilizing the Caregiver Strain Index (CSI) also assessed perceived caregiver burden by mothers of SMA patients . The study found 76% of mothers had a high caregiver burden, yet 77% also maintained paid employment.
It is also worth noting that a majority of respondents reported utilizing additional caregiving; this support was likely from another family member (unpaid) or a professional (paid). The need for additional support suggests our study may underestimate the impact of the disease on the family and the society. A recent health technology assessment for an SMA treatment acknowledged more than one caregiver may be involved in the care of patients, however as the HRQoL impact remains difficult to quantify for each caregiver, the final assessment only included one caregiver . In this study, we found despite the majority of the sample population earning >$20,000 annually, 71% of those receiving additional paid support were also Medicaid beneficiaries. Medicaid, typically limited to low-income people, is also available to those with severe disabilities, such as SMA, with higher incomes to cover benefits such as long term care . More research is needed in this area to better understand how the disease may affect multiple caregivers.
Furthermore, this study showed that despite reaching a higher educational threshold than the national average, as 56% of caregivers held an undergraduate and/or graduate degree compared with the national average of 31% in 2017 (US Census), only 40% were employed full-time . Employed caregivers also reported about 15% of the time they spent caring for their patients was time spent away from paid work. Given the vast majority of caregivers in the survey were parents, the monthly time investment for the management and treatment of SMA may be seen as prohibitive to maintaining full time employment.
As with any survey recall bias may be a concern, however the impact should be minimal as the questions were formulated with specific timeframes (i.e., ‘in a typical month’, ‘today’, etc.). Furthermore, while we provided the mean estimates for the data points, the large SD indicate there is much variability. Outliers who reported the entire day (24 hours) was spent working with the individual for whom he/she cared, skewed the results to a higher average. However, this is to be expected as each patient and family are unique. Caregivers were responsible for patients on a spectrum, where some likely required around-the-clock care and others maintained some level of independence.
The results of this study indicate there is plausible rationale for lost productivity and absenteeism that are not formally assessed at present when therapies are evaluated for cost-effectiveness. The findings of this study are in line with other studies that have assessed caregiver burden and stress prior to the introduction of the disease modifying therapies [13, 14, 26]. A holistic approach to SMA care should also include the impact on the caregiver’s quality of life.
The caregiver impact assessed in this study only captures a fraction of the disease burden on the family and society. For example, 78% of respondents reported receiving additional support (paid or unpaid), as such the impact on the additional caregivers also needs to be considered. In addition, 40% of the respondents reported being employed full time, which suggests there is significant indirect cost associated with lost productivity of unemployment or reduced productivity (absenteeism) for employed caregivers.
This survey was distributed by an email listserv from a patient advocacy group that may limit the generalizability of these results. The survey participants may have been more engaged with the advocacy group and therefore potentially more likely to take time to inform the study with their responses. As part of the survey design, caregivers of older patients (≥ 18 years old) were not recruited for this study. Additionally, the sample size was limited to 45 caregivers and the sample may not be representative of all SMA caregivers. Furthermore, the survey was limited to how respondents felt at a single point in time. While the intent of the questionnaire was to assess the time expenditure on the medical management of SMA, the various activities specific to patients with SMA, namely type 1, leave patients entirely dependent upon their caregivers. Therefore, the caregivers interpretation of the questions may have been skewed as there is no clear cut differentiation between ‘normal’ and SMA care for these caregivers . Lastly, while most of SMA patients were receiving treatment with nusinersen, due to the small sample size and relatively short duration of treatment, it is premature to assess the impact of treatment on caregiver outcomes within this study. Future longitudinal studies are needed to further understand how the impact of the disease may change as the treatment landscape continues to evolve and patient outcome continue to improve over time.