Predicting dysphagia onset in patients with ALS: the ALS dysphagia risk score

Purpose: For patients diagnosed with ALS, dysphagia can result in aspiration, malnutrition, and mortality. The purpose of this study was to develop a clinical prediction model capable of identifying patients with ALS at imminent risk for developing swallowing complications. Methods: A retrospective cohort study using the Pooled Resource Open-Access ALS Clinical Trials Database (PRO-ACT) was conducted. After dividing the PRO-ACT database into development and validation cohorts with dysphagia defined from the ALS Functional Rating Scale (ALSFRS), a multivariable Cox proportional hazards regression model estimated the probability of dysphagia at 3, 6, and 12-months with subsequent evaluation of model discrimination and calibration. Results: With 2057 participants in the development cohort and 1891 in the validation cohort, the Cox model included 7 clinical variables: spinal-onset; bulbar, fine and gross motor ALSFRS subscale scores; respiratory impairment; functional progression rate; and time from diagnosis. The cumulative incidence of dysphagia was 18% at 3-months, 29% at 6-months, and 45% at 12-months. The mean predicted probability of dysphagia development ranged from 4.5% in the bottommost risk decile to 40% in the topmost decile at 3 months, 10%-72% at 6 months, and 25%-93% at 12 months. In the validation cohort, the model had good discrimination and calibration with an optimism corrected c-statistic of 0.70 and calibration slope of 0.96. Conclusions: The ALS dysphagia risk score can be used to identify patients with ALS at high risk for self-reported dysphagia development who would benefit from a comprehensive swallowing assessment and proactive dysphagia management strategies.