SMA patient impacts measured by new PROfuture questionnaire set
They gauge areas currently unexplored by other tools, researchers say
A group of questionnaires called PROfuture can meaningfully measure a variety of symptoms of spinal muscular atrophy (SMA) that impact patients, a study reported.
“The PROfuture questionnaires, developed by patients for patients in the current era of new treatments for SMA, can help to better characterize the impact of SMA on different areas of patients’ lives that are currently unexplored by other tools,” researchers wrote.
To assess how well the questionnaires measured specific domains affected by the disease, the team investigated reliability and how scores differed based on SMA type and patients’ ability to walk or sit. They identified some changes to the surveys to improve these metrics. With these changes, PROfuture captured SMA features that other common rating scales do not cover.
The study, “Preliminary psychometric validation of patient-reported outcomes relevant to individuals with spinal muscular atrophy and their caregivers,” was published in the Orphanet Journal of Rare Diseases.
10 questionnaires each focus on different areas
SMA is a genetic condition in which muscles progressively become weaker and waste away. A variety of other symptoms, including fatigue and difficulty swallowing, speaking, and breathing, may also occur. Symptoms and care requirements mean “SMA usually has a huge impact on the health-related quality of life of patients and their families,” the research team noted.
Standardized scales and questionnaires are used to track disease progression and response to treatment. These focus on motor function and may not capture other features that have a large impact on quality of life. To address this, researchers in Spain built the PROfuture questionnaires based on focus groups made up of SMA patients and caregivers that were organized by the Spanish SMA Foundation (FundAME).
“The objective of these groups was to obtain information on the impact of the disease on patients’ lives, including physical, psychological, and social aspects, while considering the different phenotypes [traits] of the disease,” the scientists wrote.
Ten domains or questionnaires were developed featuring a set of 142 items. The 10 different areas are: fatigability, pain, scoliosis (a sideways curvature of the spine) and contractures, feeding, breathing and voice, sleep and rest, vulnerability, infections and hospitalizations, time spent in care, and mobility and independence.
The objective of these groups was to obtain information on the impact of the disease on patients’ lives, including physical, psychological, and social aspects, while considering the different phenotypes [traits] of the disease.
A computerized system was designed to only present relevant questions to a specific patient based on health data and variables such as age, motor function level, and use of a wheelchair.
For PROfuture to be useful, its results need to be reliable and able to validly differentiate between groups based on the type and severity of SMA symptoms. This study statistically measured how well the questionnaires met those requirements.
Study captured results from across SMA spectrum
A total of 160 people from a Spanish SMA registry, or their parents if the patients were younger than 12, participated in the study. SMA patients had a mean age of 18; 20% had type 1 SMA, 51.9% had type 2, and 28.1% had type 3. Parents answered all questions for participants younger than 15 and some questions for participants ages 16 to 20.
First, the researchers used preset criteria to remove items that tended to have many missing values, were skewed towards extremes, or failed to meet other reliability standards. These addressed aspects of feeding, breathing and voice, vulnerability, infections and hospitalizations, and mobility and independence. Overall, higher scores indicated more severe symptoms.
Total scores were calculated for each questionnaire, with the exceptions of sleep and rest and infections and hospitalizations. “The small number of items in these questionnaires makes them useful to assess their respective areas, without the need for a total score,” the investigators wrote.
Scores in these categories could differentiate between SMA subgroups. For example, scores related to feeding, breathing and voice, and mobility and independence were highest in people with type 1 SMA and lowest in people with type 3.
Scoliosis and contractures scores differed between individuals who couldn’t sit, those who could sit but not walk, and patients who could walk. They were worst in participants who could not sit and best in those who could walk.
In terms of study limitations, the scientists said recruiting participants from a self-reported registry may have biased results by overrepresenting those who were more engaged or proactive. However, having data from a very diverse group of patients meant the study captured results from across the spectrum of SMA, the team noted.
“PROfuture is a new set of patient-reported outcome measures, specifically designed by and for individuals living with spinal muscular atrophy and their caregivers,” the scientists wrote. “Future studies will help strengthen the evidence regarding its reliability and validity.”
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