Researchers discovered that patients with spinal muscular atrophy (SMA) of all ages had a higher all-cause mortality rate in the pretreatment era compared to age-matched controls, as published in Neurology and Therapy.
“There is little information about survival of SMA patients into adulthood, and it is commonly accepted that patients with later-onset SMA, who often live to older ages, have a mortality rate similar to the general population,” Viscidi et al wrote.
In addition, many studies investigating SMA survival do not include a control group for comparison. They hence conducted a large, retrospective cohort study using data from US electronic health records that were collected during the pretreatment era, prior to the approval of nusinersen in 2016.
“The database encapsulates all demographics and US census divisions and regions, and includes patients with all types of insurance in the US, both private and public,” the authors said.
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The researchers identified 5179 patients with SMA and matched them to 51,152 controls. Around 12% of patients with SMA were under the age of 13 years upon diagnosis, while 31% were above the age of 60 years.
The results demonstrated that SMA cases across all age groups had a 1.8-fold higher mortality rate compared to matched controls. Looking into SMA type 3 specifically, mortality rates among patients likewise exceeded controls.
“This finding suggests that, in the pre-treatment era, SMA patients of all ages have a higher mortality rate than the general population, including older patients who survive into adulthood and those with SMA type III,” Viscidi et al wrote.
The significance of this study is that it is 1 of the first to analyze mortality rates among patients with SMA with age-matched controls in a real-world sample. “Our results suggest the need for improvements in the care and management of patients with SMA, regardless of age or SMA type,” the authors concluded.
Viscidi E, Juneja M, Wang J, et al. Comparative all-cause mortality among a large population of patients with spinal muscular atrophy versus matched controls. Neurol Ther. Published online December 22, 2021. doi:10.1007/s40120-021-00307-7