AUTHOR=Pinto Susana , de Carvalho Mamede 

TITLE=SVC Is a Marker of Respiratory Decline Function, Similar to FVC, in Patients With ALS

JOURNAL=Frontiers in Neurology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2019.00109

DOI=10.3389/fneur.2019.00109

ISSN=1664-2295

ABSTRACT=<p><bold>Introduction:</bold> 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).</p><p><bold>Methods:</bold> 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.</p><p><bold>Results:</bold> 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 (<italic>p</italic> &lt; 0.001). FVC and SVC were strongly correlated at study entry (<italic>r</italic><sup>2</sup> = 0.98, <italic>p</italic> &lt; 0.001) and FVC and SVC decays between first evaluation and 6 months after were the only significant prognostic variables of functional decay (<italic>p</italic> &lt; 0.001).</p><p><bold>Conclusion:</bold> 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.</p>