Early Identification of SMA May Help Curb Costs of Disease

Identifying spinal muscular atrophy (SMA) early and initiating treatment can help reduce the total societal costs that the disease accrues, say researchers, whose study findings published in Developmental Medicine and Child Neurology identified a wide range of costs between treated and untreated patients.

Compared with patients who received treatment once they started exhibiting symptoms, those living with SMA and subsequently treated as result of early testing—either due to newborn screening or diagnosis of a sibling—had lower total costs. Costs identified by the study included direct medical, direct nonmedical, and indirect costs, such as the societal loss of patient or caregiver productivity.

When excluding the cost of treatment, costs were significantly lower among the 14 patients identified by early screening than among the 42 patients identified by symptoms. The researchers highlighted the small cohort of patients identified by early screening as a limitation of the study.

“The yearly total cost differences between treated symptomatic patients and patients not identified by symptoms were much lower in patients with 4 copies of the gene than in patients with 2 or 3 copies,” explained the researchers. “Patients with 4 copies present with significantly less severe disability, regardless of whether they are treated early or indeed at all; thus, the difference due to early diagnosis is less. The positive impact of early treatment on the health status of patients with 2 and 3 copies of the SMN2 gene also translates into substantial cost savings.”

Across both groups of treated patients and a third group of 93 patients who were untreated, patients who had 2 copies of the SMN2 gene had the highest accrued costs. As a whole, the group of untreated patients had lower total costs than the 2 groups of treated patients due to the high costs of SMA treatment.

The study also assessed quality of life (QOL) among the groups of patients. Across the PedsQL Generic Core Scale (GCS) and PedsQL Neuromuscular module (NMM) subscales, scores were higher in patients identified by early screening than the other 2 groups, although the sample size was not large enough for a formal comparison.

Other QOL findings included:

• On the PedsQL Family Impact scale, patients identified by early screening were as affected as treated patients who were identified by symptoms and untreated patients
• On the PedsQL Family Impact and EQ-5D Visual Analogue Scale subscales, differences were not significant between treated patients identified by symptoms and untreated patients

“Our QOL data on the PedsQL GCS and NMM are very comparable with previous reports. In contrast, the EQ-5D-3L utility scores reported by López-Bastida et al were much lower (average = 0.16, SD = 0.44, maximum = 1) than observed with the EQ-5D for treated and untreated symptomatic patients with 2 or 3 SMN2 copies (between 0.34 and 0.45),” detailed the researchers. “This could be due, at least in part, to a difference in the populations studied: Of the patients who responded to the EQ-5D in our study, 10%, 58%, and 32% of patients were classified as SMA types 1, 2, and 3, respectively, whereas the distribution was 10%, 74%, and 16% in the in the López-Bastida et al analysis. Thus, the previous study included fewer patients with a milder phenotype.”

The researchers noted that treated patients identified by early screening were much younger than the rest of the patients, which had a direct impact on their QOL findings, as questionnaires, with the exception of the PedsQL Family Impact scale, were not valid before the age of 2 years and were filled out by parents of patients younger than 6 years. The group flagged that parents generally rated the family impact of SMA as severe even in cases where the child had no symptoms, likely resulting from a fear that the disease would get worse.

Reference

Dangouloff T, Hiligsmann M, Deconinck N, et al. Financial cost and quality of life of patients with spinal muscular atrophy identified by symptoms or newborn screening. Dev Med Child Neurol. Published online June 8, 2022. doi:10.1111/dmcn.15286