Brief Research Report ARTICLE
SVC is a marker of respiratory decline function, similar to FVC, in patients with ALS
- 1Institute of Molecular Medicine, Faculty of Medicine, University of Lisbon, Portugal
Respiratory function is a critical predictor of survival in amyotrophic lateral sclerosis (ALS). The role of respiratory function as predictor of functional decay in ALS is not fully established. We aimed to determine if slow vital capacity (SVC) is a predictor of functional loss in ALS.
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 with the respiratory tests, SVC and forced vital capacity (FVC). Significant independent variables of functional decay as determined by an ALSFRS value lower than 0.92/month were assessed by univariate Kaplan-Meier log-rank test and multivariate Cox proportional hazards model.
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±12.9months; 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 (r2=0.98, p<0.001) and FVC and SVC decays between first evaluation and six months after were the only significant prognostic variables of functional decay (p<0.001).
FVC and SVC decay are inter-changeable in predicting functional decay in ALS. Any pharmacological intervention reducing the rate of FVC and SCV decline should have a positive impact on the global functional impairment, which has relevant implications for clinical trials design and interpretation.
Keywords: Amyotrofic Lateral Sclerosis, slow vital capacity (SVC), functional outcome, predictor, rate of progression
Received: 29 Jul 2018;
Accepted: 28 Jan 2019.
Edited by:Francesca Trojsi, Università degli Studi della Campania Luigi Vanvitelli Caserta, Italy
Reviewed by:Pierluigi Carratù, Università degli Studi di Bari, Italy
Rossella Spataro, University of Palermo, Italy
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.
* Correspondence: Prof. Susana Pinto, Institute of Molecular Medicine, Faculty of Medicine, University of Lisbon, Lisbon, Portugal, firstname.lastname@example.org