Table 2. Characteristics of the EHR-derived cohort of multiple sclerosis (MS) patients and the subset of patients who receive care at a subspecialty MS Centera.
| Parameter | EHR-derived Cohort (n = 5,495) | MS Center Subset (n = 4,241) |
| Sex (% female) | 73% | 73% |
| Race/Ethnicity (% non-Hispanic white) | 72% | 75% |
| Age at first ICD-9 code for MS, years (median [Q1–Q3]) | 41 [33–49] | 40 [32–49] |
| Duration of follow-up, years (median [Q1–Q3]) | 8.4 [3.5–13.7] | 9.1 [4.3–14.4] |
| Number of ICD-9 code for MS per patient (median [Q1–Q3]) | 22 [8–49] | 26 [9–55] |
| Number of MRI brain per patient (median [Q1–Q3]) | 6 [3]–[12] | 8 [4]–[14] |
| Number of MRI cervical spine per patient (median [Q1–Q3]) | 4 [2]–[6] | 4 [2]–[7] |
| Number of entries by a MS neurologist per patient(median [Q1–Q3]) | 47 [13–124] | 56 [12–139] |
| Number of prescriptions for MS disease modifyingtreatment per patient (median [Q1–Q3]) | 5 (2–13) | 6 (3–15) |
| Receiving MS disease modifying treatment, % | 49% | 55% |
a
A subset of the patients in the EHR-derived MS cohort receives neurological care at the Partners MS Center where neuroimaging and clinical outcomes are available. For comparison, our cohort shares similar basic demographic characteristics as an independent MS patient registry from the North American Research Committee on Multiple Sclerosis (NARCOMS): 73% of the NARCOMS patients are female, 90% are self-described White, mean age at diagnosis is 37 years, and 52% of the patients are receiving immune modulatory therapy [32].
Abbreviation: ICD-9 = 340 is the diagnostic code for MS.