Healthcare use is elevated two decades before a first demyelinating event and differs by age and sex
Bibliographic record
Abstract
OBJECTIVE: Elevated healthcare use before multiple sclerosis (MS) onset suggests earlier opportunity to identify MS. Yet their timing and sociodemographic effects are unclear. We examined rates of healthcare use (and by age/sex) for >two decades pre-MS onset. METHODS: We identified people with MS (PwMS) using administrative data from Canada (Ontario) and Sweden (1991-2020) ("administrative" cohort), and the Swedish MS Registry ("clinical" cohort). The first MS/demyelinating diagnostic code (administrative) or symptom onset (clinical) defined MS onset. We compared annual rates of healthcare use (hospital, physician, and emergency-room [ED]) pre-onset between PwMS and up to five matched population controls using negative binomial regression, and by age/sex. RESULTS: The administrative cohort = 35,018/136,007 PwMS/controls (Ontario), and 10,269/51,297 (Sweden). Rates of healthcare use were higher for PwMS than controls up to 28 (of 29) years (Ontario) and up to 15 (of 19) years (Sweden) pre-onset. Annual healthcare use rose steadily as onset approached, particularly escalating 7 years pre-onset in Ontario (e.g., hospital visit rate ratios [RRs] exceeded 1.30), and 6 years in Sweden (physician visit RRs > 1.10). RRs peaked the year pre-onset (ED visits [Ontario] = 3.04; 95% CI: 2.94-3.13, physician visits [Sweden] = 2.51; 95% CI: 2.44-2.59). In the year pre-onset, RRs were disproportionately higher for males (ED RRs [Ontario] = 3.30; 95% CI: 3.13-3.48 vs. females = 2.90; 95% CI: 2.79-3.02), and dropped steadily by age (physician visit RRs [Sweden] = 2.61/2.27/1.97/1.72 for 50/40/30/20-year-olds). The smaller clinical cohort (7604/37,974 PwMS/controls) exhibited similar patterns, albeit more modest, with RRs elevated up to 5 years pre-onset (physician visit RR [year-5] = 1.08; 95% CI: 1.02-1.14; RR [year-1] = 1.39;1.33-1.46). INTERPRETATION: Higher healthcare use was evident decades before MS onset, escalating 6-7 years pre-onset, peaking the year before, being disproportionately higher for males and older PwMS.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".