Antibiotics prescribed, stratified by age and tier classification system,19 to 204 313 patients in Ontario, 2011/12 to 2015/16*
| Classification† | < 2 | Patient age, yr; no. (column %) of prescriptions | |||
|---|---|---|---|---|---|
| 2–18 | 19–64 | ≥ 65 | All ages | ||
| Tier 1 | 591 (4.5) | 5438 (10.2) | 12 305 (7.1) | 5581 (8.0) | 23 915 (7.7) |
| Tier 2a | 0 (0.0) | 25 (< 0.1) | 19 532 (11.2) | 9325 (13.4) | 28 882 (9.3) |
| Tier 2b | 1622 (12.4) | 10 058 (18.8) | 9971 (5.7) | 2194 (3.1) | 23 845 (7.7) |
| Tier 2c | 927 (7.1) | 3129 (5.8) | 26 721 (15.4) | 7513 (10.8) | 38 290 (12.3) |
| Tier 3 | 4094 (31.3) | 12 547 (23.5) | 16 756 (9.6) | 3858 (5.5) | 37 255 (12.0) |
| Excluded | 3509 (26.8) | 10 962 (20.5) | 47 224 (27.2) | 20 716 (29.7) | 82 411 (26.6) |
| No documented encounter | 2354 (18.0) | 11 308 (21.1) | 41 288 (23.8) | 20 593 (29.5) | 75 543 (24.4) |
| Total no. (row %) of antibiotics | 13 097 (4.2) | 53 467 (17.2) | 173 797 (56.0) | 69 780 (22.5) | 310 141 (100.0) |
↵* Maximum 1 antibiotic per encounter.
↵† Tier 1 = conditions for which antibiotics are always indicated (expected prescribing rate 100%), tier 2a = conditions for which antibiotics are frequently indicated (expected prescribing rate 51%–99%), tier 2b = conditions for which antibiotics are sometimes indicated (expected prescribing rate 21%–50%), tier 2c = conditions for which antibiotics are rarely indicated (expected prescribing rate 1%–20%), tier 3 = conditions for which antibiotics are never indicated (expected prescribing rate 0%).