The initiation of early non-invasive ventilation (NIV) often involves a careful balance between tolerance and effectiveness. In amyotrophic lateral sclerosis (ALS) patients, the establishment of a strategy, including the decision to focus on adhering to a cut-off, setting specific targets, or correcting all events, is crucial. To identify factors at 1month after early at-home NIV initiation that are associated with improved survival in ALS patients. We explored the impacts of adherence (ADH), quality of treatment, and NIV parameters at 1month after early at-home NIV initiation on patient survival. We conducted a retrospective study of 184 ALS patients at the Bordeaux ALS Centre for whom NIV was initiated between September 2017 and June 2021, and we collected data for a minimum period of 2years after the last patient included. The primary outcome was the risk of death according to baseline characteristics of our population and the NIV parameters and monitoring during the early NIV initiation period. The secondary outcomes were association with NIV ADH during the early NIV initiation period on prognosis, and NIV ADH cut-off for good versus poor prognosis. Among the 178 ALS patients analysed, we found that quality of NIV treatment and device settings did not significantly influence prognosis. However, low ADH was significantly associated with a higher risk of death. The use of NIV for > 5h/day during the early NIV initiation period was linked to a decreased risk of death [hazard ratio = 0.4; 95% confidence interval: 0.27-0.9]. The use of NIV for > 5h/day during the early NIV initiation period was associated with increased survival.