Muhannad Seyam1, Richard Hubbell1, Diantha Howard1, Joan Skelly2, Waqar Waheed1, Rup Tandan1
1University of Vermont Medical Center, 2University of Vermont
Objective:
To investigate the value of forced vital capacity (FVC) upon clinical presentation and its rate of decline for predicting survival in ALS.
Background:
ALS is a fatal neurodegenerative disorder of the motor system, leading to death due to progressive neuromuscular respiratory insufficiency in most patients.
Design/Methods:
This retrospective study in our academic center included 153 patients between 2016 and 2019 who were followed in the ALS clinic and for whom complete datasets were available. Initial FVC and its 3-month change were used for survival analysis via Kaplan-Meier method and Cox regression model. We defined two major patient groups based on their initial FVC (“high FVC” if > median, “low FVC” if < median) and subgroups based on their rate of FVC decline: (I) “initial high FVC/fast decline”, (II) “initial high FVC/slow decline”, (III) “initial low FVC/fast decline”, and (IV) “initial low FVC/slow decline”. These subgroups were compared for demographic, disease-related, and survival characteristics.
Results:
Initial FVC above the median (>85%) was associated with a survival of 39 months, while FVC below the median was associated with a survival of 16 months (p <0.001). Rate of FVC decline was also significantly associated with survival (p <0.001): patients with a 3-month FVC slope ≥ the median slope had a median survival of 41 months, while patients with a 3-month FVC slope below the median slope had a survival of 16 months. Subgroup analysis (p <0.001) showed that patients with “initial low FVC/fast decline” had a median survival of 13 months, while 26 months for patients with “initial low FVC/slow decline” and 47 months for patients with “initial high FVC/slow decline”.
Conclusions:
Initial FVC and its 3-month decline is a reliable predictor for survival. This simple metric can be utilized by clinicians and their patients to guide further management, as well as by researchers designing clinical trials.