Early treatment with noninvasive positive pressure ventilation prolongs survival in Amyotrophic Lateral Sclerosis patients with nocturnal respiratory insufficiency

Abstract

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease, which rapidly leads to chronic respiratory failure requiring mechanical ventilation. Currently, forced vital capacity (FVC) < 50% is considered as physiologic marker for admitting patients to Noninvasive Positive Pressure Ventilation (NPPV) intervention, although it has been recently shown the median survival of patients with baseline FVC < 75% much shorter than median survival of patients with baseline FVC > 75%, independently by any treatment.

Aim: To assess the role of NPPV in improving outcome of ALS, a retrospective analysis was performed to investigate 1 year survival of ALS patients with FVC < 75% and nocturnal respiratory insufficiency, treated with NPPV, compared to a well-matched population of ALS patients, who refused or was intolerant to NPPV.

Methods: We investigated seventy-two consecutive ALS patients who underwent pulmonary function test. Forty-four presented a FVC > 75% and served as control group. Twenty-eight patients presented a FVC < 75% and showed, at polysomnography analysis, nocturnal respiratory insufficiency, requiring NPPV; sixteen were treated with NPPV, while twelve refused or were intolerant.

Results: Increased survival rate at 1 year in patients with FVC < 75% treated with NPPV, as compared to those who refused or could not tolerate NPPV (p = 0.02), was observed. The median rate of decline in FVC% was slower in NPPV patients than in patients who did not use NPPV (95% CI: 0.72 to 1.85; p < 0.0001).

Conclusion: This report demonstrates that early treatment with NPPV prolongs survival and reduces decline of FVC% in ALS.

Figure 1

Kaplan-Meier plots of survival in 72 patients affected by amyotrophic lateral sclerosis (ALS) from the initiation of NPPV. (Black circle) = 44 patients with ALS with FVC > 75%, (Black triangle) = 16 patients with ALS with FVC < 75% treated with NPPV, (Black square) = 12 patients with ALS with FVC < 75% not treated with NPPV. ALS patients with FVC < 75% treated with NPPV vs. patients with ALS with FVC < 75% intolerant to NPPV: χ² 5.32; *p = 0.02. Patients with ALS with FVC > 75% vs. patients with ALS with FVC < 75% treated with NPPV: χ² = 0.408 p = 0.5. Patients with ALS with FVC > 75% vs. patients with ALS with FVC < 75% not treated with NPPV: χ² = 15.4; p < 0.0001.

Figure 2

Slope of FVC% in 1 year between survivors of the groups 2 and 3. Blue line: Group 2 (12) (NPPV); Red line: Group 3 (4) (no NPPV). X axis: months, Y axis: FVC%. FVC% slope change per month in group 2 (1.52 ± 0.3) and group 3 (2.81 ± 0.8); p < 0.0001.