Predictors for successful non-invasive ventilation in patients with neuralgic amyotrophy and phrenic nerve involvement

<bold>Background</bold> Patients with neuralgic amyotrophy (NA) and involvement of the phrenic nerve are mostly symptomatic and might benefit from home non-invasive ventilation (NIV). However, predictors of successful NIV in these patients are currently unknown. This study aimed to study the efficacy and potential predictors for successful home NIV in patients with NA. <bold>Methods</bold> Data of all NA patients initiated on chronic NIV by the Centre of Home Mechanical Ventilation of Maastricht UMC+ between September 2008 and April 2023 were retrospectively analyzed. Primary outcome was treatment success, defined as chronic continuation of NIV or successful step-down from NIV. Univariate and multivariate analyses using Cox proportional hazard models were used for statistical analysis of predictors of success. <bold>Results</bold> 54 patients (mean age 62.5±10.9y, 72.2% males) were included. Mean delta FVC with posture at NIV initiation was 35.1±19.6 %pred. Mean compliance to NIV of 6.37 [3.55–8.11] hours per day. 38 (70.4%) patients continued to use NIV over a mean of 4.9 years of follow-up. Six (11%) stepped-down from NIV, accompanied by improvement in symptoms and lung function. Delta FVC(pred%) at NIV initiation was an independent factor for successful NIV (HR=0.947; confidence interval=[0.91–0.99]). During follow-up, delta FVC(pred%) declined, particularly in the first two years after initiation of NIV. <bold>Conclusion</bold> In 70% of patients with NA with diaphragm involvement and initiated on home NIV, the intervention was successful according to the used definition. This study identified delta FVC(pred%) at start as a clinical important independent predictor for a successful NIV in these patients.