Self-controlled case series analyses for the association between stimulant medication treatment and first medically-attended injury event, stratified by case characteristics
| Characteristic | Cases in analysis (n) | Adjusted IRR (95% CI)* |
|---|---|---|
| All stimulants | 328 | 0.68 (0.50 to 0.91) |
| Gender | ||
| Male | 285 | 0.63 (0.50 to 0.91) |
| Female | 43 | 1.01 (0.46 to 2.21) |
| Age at initial prescription, years | ||
| 1–5 | 10 | 0.52 (0.11 to 2.48) |
| 6–9 | 151 | 0.78 (0.52 to 1.18) |
| 10–14 | 140 | 0.62 (0.39 to 0.97) |
| 15–18 | 27 | 0.85 (0.28 to 2.56) |
| Initial medication type | ||
| MPH | 252 | 0.70 (0.50 to 0.98) |
| Long-acting MPH | 71 | 0.73 (0.37 to 1.44) |
| Dexamphetamine | 5 | N/A |
*The IRR estimates the rate ratio of injury comparing treated periods to untreated periods. All estimates are self-controlled and additionally adjusted for age in 2-year categories and season, except age group estimates, which are adjusted for season only.
IRR, incident rate ratio; MPH, methylphenidate.