Natural History of Type 1 Spinal Muscular Atrophy in a Series of Argentinian Children

Abstract

Background: SMA1 natural history is characterized by early development of chronic respiratory failure. Respiratory interventions in type 1 SMA infants are subject to great practice variability. Nusinersen, has been recently approved in Argentina. The advent of novel treatments has highlighted the need for natural history studies reporting disease progression in type 1 SMA. Objective: To analyze the progression, respiratory interventions and survival based on the type of respiratory support in type 1SMA patients, in a third level pediatric hospital in Argentina. Methods: Cohort of SMA1 patients followed at the Interdisciplinary Program for the Study and Care of Neuromuscular Patients (IPNM). Patient survival was analyzed by using the Kaplan-Meier method. Log-rank test was performed to compare the survival curve for three respiratory intervention groups. Results: 59 patients. Mean age of symptom onset was 2.19 (±1.4) months, age at diagnosis was 3.9 (±2.1) months. Patients developed respiratory failure at 5.82 months (±2.32) and 13.8 months (±5.6) in Type 1B and Type 1C, respectively (p < 0.001) 53 p were SMA1B. Three copies were found in 1/6 SMA1C. Respiratory interventions: SRC 23 p (56.1%); SRC + NIV 8 p (19.5%); SRC + IV 10 p (24.4%). 8 patients were already on invasive ventilation when included in the IPNM. Patients with invasive ventilation showed longer survival. Conclusions: This series provides valuable information on respiratory intervention requirements and life expectancy in children with SMA1 before the implementation of novel treatments that increase the expression of the SMA protein.

Survival analysis and life expectancy of pediatric patients with spinal muscular atrophy in Thailand

“…Age at onset critically impacts survival outcomes in patients with SMA. Our findings indicated onset ages of 3.2 months for SMA type 1, 11.1 months for type 2, and 4.3 years for type 3, consistent with prior studies on SMA types 1 and 2 [ 12 , [20] , [22] , [23] [ 24 ]]. However, our results for SMA type 3 diverged, potentially due to our smaller cohort.…”

Comprehensive profile and natural history of pediatric patients with spinal muscular atrophy: A large retrospective study from China

“…Respiratory complications are one of the most serious risks of mortality in SMA type 1 patients (27). We found that the peak time of severe respiratory complications (hospitalization required) was 3-6 months in SMA 1a, 7-12 months in SMA 1b, and 1-3 years in SMA 1c, mimicking one report from Argentinian in 2020 (28), which was mainly consistent with the survival situation in SMA type 1 patients. A high proportion of severe respiratory complications was observed; however, an assistant coughing machine and ventilation were not widely accepted in SMA type 1 patients.…”

Risk factors for recurrent respiratory tract infections or acute respiratory failure in children with spinal muscular atrophy

“…SMA of type 1 is more severe, and both the age at death and the number of people using ventilators are respectively earlier and more than those in other SMA types. 1,10 Most children with SMA type 1 over two years of age need tracheotomy or all-day noninvasive ventilation for survival. 11 Children with type 2 have a progressive decline in overall function and need noninvasive ventilation from five to thirteen years old.…”