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

Table 3 **Symptoms/diagnoses* and median time to diagnosis**

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

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.
*Observed at a frequency < 10% with a prevalence ratio ≥ 5 compared with the Medicare cohort.
^†In the eight quarters before ALS diagnosis, not including the quarter of diagnosis (n = 399).
^‡Prevalence in the Medicare cohort.
^§Percentage of patients in the ALS cohort having a given symptom/ the percentage of patients in the Medicare cohort with the same symptom.
^‖In the time to diagnosis cohort (n = 272).

ISSN: 1471-2377