Variation in non-invasive ventilation use in amyotrophic lateral sclerosis

Objective: We sought to examine prevalence and predictors of non-invasive ventilation (NIV) in a composite cohort of amyotrophic lateral sclerosis (ALS) patients followed in a clinical trials setting (PRO-ACT database). Methods: NIV initiation and status were ascertained from response to question 12 of the revised ALS functional rating scale (ALSFRS-R). Factors affecting NIV use in patients with forced vital capacity (FVC) ≤ 50% of predicted were examined. Predictors of NIV were evaluated by Cox proportional hazard models and generalized linear mixed models. Results: Among 1,784 patients with 8,417 simultaneous ALSFRS-R and FVC% measures, NIV was used by 604 (33.9%). Of 918 encounters when FVC% ≤ 50%, NIV was reported in 482 (52.5%). Independent predictors of NIV initiation were lower FVC% (hazard ratio HR 1.27, 95% CI: 1.17-1.37 for 10% drop), dyspnea (HR 2.62, 95% CI: 1.87-3.69), orthopnea (HR 4.09, 95% CI: 3.02-5.55), lower bulbar and gross motor subscores of ALSFRS-R (HRs 1.09 (95% CI: 1.03-1.14) and 1.13 (95% CI: 1.07-1.20) respectively, per point), and male sex (HR 1.73, 95% CI: 1.31-2.28). Adjusted for other variables, bulbar onset did not significantly influence time to NIV (HR 0.72 (95% CI: 0.47-1.08)). Considerable unexplained variability in NIV use was found. Conclusion: NIV use was lower than expected in this ALS cohort that was likely to be optimally managed. Absence of respiratory symptoms and female sex may be barriers to NIV use. Prospective exploration of factors affecting adoption of NIV may help bridge this gap and improve care in ALS.