Noninvasive Ventilation Use Is Associated with Better Survival in Amyotrophic Lateral Sclerosis

Abstract

Rationale: Noninvasive ventilation (NIV) is standard of care in amyotrophic lateral sclerosis (ALS), yet few data exist regarding its benefits.Objectives: We sought to identify whether the use of NIV was associated with survival in ALS.Methods: This was a single-center retrospective cohort study of 452 patients with ALS seen between 2006 and 2015. We matched one or more NIV subjects (prescribed NIV) to non-NIV subjects (never prescribed NIV) without replacement. The outcome was time from NIV prescription date (NIV subjects) or matched date (non-NIV subjects) until death. We performed a multivariable Cox proportional hazards model with NIV hourly usage as a time-varying covariate and stratified by matched groups.Results: After creating 180 matched groups and adjusting for age, body mass index, ALS Functional Rating Scale Revised dyspnea score, and hourly NIV use, NIV was associated with a 26% reduction in the rate of death compared with non-NIV subjects (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.57-0.98; P = 0.04). Among those with limb-onset ALS, NIV subjects had a 37% lower rate of death compared with non-NIV subjects (HR, 0.63; 95% CI, 0.45-0.87; P = 0.006). Among NIV subjects, we found that NIV use for an average of ≥4 h/d was associated with improved survival.Conclusions: NIV use was associated with significantly better survival in ALS after matching and adjusting for confounders. Increasing duration of daily NIV use was associated with longer survival. Randomized clinical trials should be performed to identify ideal thresholds for improving survival and optimizing adherence in ALS.

Keywords: amyotrophic lateral sclerosis; matching; noninvasive ventilation; respiratory failure; survival analysis.

Figure 1.

Survival among noninvasive ventilation subjects only, stratified by average daily use ≥4 hours (n = 121) versus <4 hours (n = 151) with 95% confidence intervals. NIV = noninvasive ventilation.

Figure 2.

Survival since noninvasive ventilation initiation for average daily use of noninvasive ventilation comparing <1 hour (n = 106), 1–3.9 hours (n = 45), 4–7.9 hours (n = 54), and ≥8 hours (n = 67). NIV = noninvasive ventilation.