SVC Is a marker of respiratory decline function, similar to FVC, in patients with ALS

• Published in: Frontiers in neurology Vol. 10; p. 109
• Main Authors: Pinto, Susana, de Carvalho, Mamede
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers 2019; Frontiers Media S.A
• Subjects: Amyotrophic lateral sclerosis; Functional outcome; Neurology; Predictor; Rate of progression; Slow vital capacity; slow vital capacity; predictor; functional outcome; rate of progression; amyotrophic lateral sclerosis
• ISSN: 1664-2295; 1664-2295
• DOI: 10.3389/fneur.2019.00109

Copyright © 2019 Pinto and de Carvalho. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Introduction: Respiratory function is a critical predictor of survival in amyotrophic lateral sclerosis (ALS). We aimed to determine if slow vital capacity (SVC) is a predictor of functional loss in ALS as compared to forced vital capacity (FVC). Methods: Consecutive ALS patients in whom respiratory tests were performed at baseline and 6 months later were included. All patients were evaluated with revised ALS functional rating scale (ALSFRS-R) and the respiratory tests, SVC, and FVC. Significant independent variables of functional decay were assessed by univariate Kaplan-Meier log-rank test and multivariate Cox proportional hazards model. A monthly decay not exceeding 0.92 in ALSFRS was considered as the time event. Results: We included 232 patients (134 men; mean onset-age 59.1 ± 11.23 years; mean disease duration from first symptoms to first visit: 14.5 ± 12.9 months; 166 spinal and 66 bulbar onset). All variables studied declined significantly between the two evaluations (p < 0.001). FVC and SVC were strongly correlated at study entry (r 2 = 0.98, p < 0.001) and FVC and SVC decays between first evaluation and 6 months after were the only significant prognostic variables of functional decay (p < 0.001). Conclusion: FVC and SVC decay are inter-changeable in predicting functional decay in ALS. Pharmacological interventions reducing the decline rate of FVC and SVC can have a positive impact on the global functional impairment, with relevant implications for clinical trials' design and interpretation. This study was partially funded through an independent grant from Cytokinetics. This project is funded by the funding reference—UID/BIM/50005/2019, project funded by Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) through Fundos do Orçamento de Estado.