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Table 3 Symptoms/diagnoses* and median time to diagnosis

From: Diagnosis pathway for patients with amyotrophic lateral sclerosis: retrospective analysis of the US Medicare longitudinal claims database

Symptom group Symptom/diagnosis Pre-ALS frequency, % Medicare frequency, % Prevalence ratio§ Median time to diagnosis from first limb/bulbar symptom, years
Nerve Chronic inflammatory demyelinating polyneuropathy 2 < 1 30.5 ND
Nerve Myopathy (including myopathy with weakness) 8 < 1 28.6 2.75
Nerve Unspecified disease of spinal cord (including myelopathy NOS) 5 < 1 19.6 2.25
Nerve Cervical/thoracic or lumbar spondylosis with myelopathy 6 1 11.2 3.50
Limb Atrophy, muscular disuse 5 1 5.0 2.75
  1. ALS, amyotrophic lateral sclerosis; ND, not determined because of small sample of patients with chronic inflammatory demyelinating polyneuropathy in the time to diagnosis cohort; NOS, not otherwise specified.
  2. *Observed at a frequency < 10% with a prevalence ratio ≥ 5 compared with the Medicare cohort.
  3. In the eight quarters before ALS diagnosis, not including the quarter of diagnosis (n = 399).
  4. Prevalence in the Medicare cohort.
  5. §Percentage of patients in the ALS cohort having a given symptom/ the percentage of patients in the Medicare cohort with the same symptom.
  6. In the time to diagnosis cohort (n = 272).