A systematic assessment of medical diagnoses preceding the first diagnosis of multiple sclerosis: Supplementary materials

Objective: To explore the occurrence of diseases and symptoms in the five years prior to diagnosis in patients with multiple sclerosis (MS) in a case-control study. Methods: Using ambulatory claims data we systematically assessed differences in the occurrence of diseases and symptoms in the five years prior to first diagnosis in patients with MS (n=10,262) as compared to patients with two other autoimmune diseases – Crohn’s disease (n=15,502) and psoriasis (n=98,432) - and individuals without these diseases (n=73,430). Results: Forty-three ICD-10 codes were recorded more frequently for patients with MS before diagnosis as compared to controls without autoimmune disease. Many of these findings were confirmed in a comparison to the other control groups. A high proportion of these ICD-10 codes represent symptoms suggestive of demyelinating events or other neurological diagnoses. In a sensitivity analysis excluding patients with such recordings prior to first diagnosis, no association...