Symptoms prior to diagnosis among a diverse patient population with amyotrophic lateral sclerosis In the USA

Amyotrophic lateral sclerosis (ALS) symptom onset is gradual and may include muscle weakness, dysarthria, dysphagia, and respiratory difficulties among others. The objective of this study is to describe sex and racial/ethnic variation in limb and bulbar symptom diagnoses before ALS diagnosis in the USA. This retrospective cohort study was conducted using Optum's de-identified Market Clarity Data with a patient identification period between January 2015 and December 2019. Cases were identified using ICD-9/10 codes and were required to have ≥3 years of continuous enrollment or EHR activity prior to diagnosis. Descriptive statistics of symptom frequency and onset were stratified by sex and race. This study identified 7121 individuals with ALS, 3303 female (46%) and 3818 male (54%). Most identified as Non-Hispanic White (67.5%), followed by African American (6.6%), Hispanic (3.6%), and Asian (0.9%), with 21.4% missing race/ethnicity. In the 3 years before ALS diagnosis, 42.9% of subjects were diagnosed with ≥1 bulbar symptom, 74.5% with ≥1 limb symptom, and 34.6% with both. Females more likely to be diagnosed than males: any bulbar 47.1% versus 39.3%, (p < 0.0001), any limb 76.0% versus 73.2%, (p = 0.007), both 38.1% versus 31.6%, (p < 0.0001). Variation by race/ethnicity was observed for limb symptoms (p < 0.0001) and both bulbar and limb symptoms (p = 0.008), but not bulbar symptoms alone (p = 0.07). Symptom onset to ALS was longer for females and varied by race/ethnicity. Females were more likely to present with bulbar and limb symptoms prior to ALS diagnosis and African American patients were more likely to present with limb symptoms than other race/ethnicities.