Use of the emergency department before pediatric-onset multiple sclerosis: a matched cohort study

Background and objectives — Higher health care use before multiple sclerosis (MS) onset could suggest a measurable prodromal phase. Emergency department (ED) utilization can provide critical information for early detection of developing health issues. However, little is known of ED utilization before onset of pediatric-onset MS (POMS). We examined ED utilization by visit rates and discharge diagnoses (conditions) before the first demyelinating event (index) in a population-based POMS cohort.

Methods — In this matched cohort study, patients with POMS (younger than 18 years) were identified through a validated algorithm using linked health administrative data from ON, Canada (2000–2020). Up to 5 demographically matched non-MS individuals per person with POMS were randomly selected. Count-based regression estimated differences in ED visit rates up to 18 years before index. Yearly relative differences, reported as rate ratios ([RRs]; 95% CI), and cumulative 18-year RRs by ED visit–related diagnoses were also reported.

Results — Among 230 patients with POMS and 621 non-MS individuals, 63%–67% were female. Both cohorts had a mean age at index of 14.01 years, with SDs of 3.78 and 3.74, respectively. The POMS cohort had higher ED visit rates, starting from 12 years before index and peaking in the year before index (adjusted RR = 4.02; 3.07–5.26) vs the non-MS cohort. The POMS cohort had higher ED use for 7 conditions in the 18-year period before index, with the highest rate observed for nervous system–related visits (RR = 5.28; 1.69–16.49), followed by mental disorders (RR = 3.05; 1.41–6.62), ill-defined signs/symptoms (RR = 2.37; 1.80–3.12), musculoskeletal conditions (RR = 2.18; 1.15–4.15), disorders of sense organs (RR = 1.91; 1.37–2.66), infections (RR = 1.67; 1.17–2.38), and respiratory system conditions (RR = 1.63; 1.14–2.35). In yearly analyses, respiratory-related ED visits were higher in the POMS cohort at 12 years before index (RR = 2.72; 1.02–7.27) while visits for 5 other conditions were higher in the year before index (specifically, ill-defined signs/symptoms = 11.74, 6.93–19.89; nervous system conditions = 9.03, 2.69–30.32; disorders of sense organs = 5.96, 3.15–11.28; other health system contacts = 5.42, 1.75–16.82; and musculoskeletal conditions = 5.12, 2.12–12.37).

Discussion — Compared with the non-MS cohort, the POMS cohort had higher ED utilization for respiratory conditions beginning 12 years before the first demyelinating event and for multiple system–related concerns in the year before. Findings may have implications for the future earlier identification of POMS, enabling prompt treatment of POMS. Limitations include small subgroup analyses, especially by age, necessitating cautious interpretation.