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Number of cases and its control moments participating in case‐crossover study in BIFAP and CPRD
| Number of cases with M controls (N%) | Number of cases with at least M controls (N%) | |||
|---|---|---|---|---|
| Control moments (M) | CPRD | BIFAP | CPRD | BIFAP |
| 1 | 530 (4.1) | 267 (4.7) | 12 853 (100) | 5412 (100) |
| 2 | 474 (3.7) | 272 (4.8) | 12 323 (95.9) | 5145 (95.1) |
| 3 | 492 (3.8) | 274 (4.8) | 11 849 (92.2) | 4873 (90.0) |
| 4 | 11 357 (88.4) | 4599 (80.6) | 11 357 (88.4) | 4599 (85.0) |
