The following variables were included in the Cox model: age (18–59, 60–69, 70–79, 80–99) years, gender, FALS status (FALS vs SALS), gene mutation (C9ORF72, SOD1, TARDBP, FUS, OPTN, no mutation identified), years of education (≤5, 6–8, 9–13, ≥14), progression rate of ALSFRS-R total score (<0.7 vs ≥0.7 point/months), ALSFRS-R bulbar score (<0.15 vs ≥0.15 points/month), ALSFRS-R fine motor score (<0.2 vs ≥0.2 points/month), ALSFRS-R gross motor score (<0.22 vs ≥0.22 points/month), ALSFRS-R respiratory score (<0.1 vs ≥0.1 points/month), FVC% (<0.50 vs ≥0.50 months). Cognitive status was included as ALS-FTD (yes vs no), ALS-ECI (yes vs no), ALS-NECI (yes vs no) ALS-Bi (yes vs no) and ALS-NCCI (yes vs no). Enteral nutrition and non-invasive ventilation were included as time-dependent variables.

ALS, amyotrophic lateral sclerosis; Bi, behavioural impairment; ECI, executive cognitive impairment; FALS, familial ALS; FTD, frontotemporal dementia; FVC%, forced vital capacity per cent of predicted; NECI, non-executive cognitive impairment; NCCI, non-classifiable cognitive impairment.