Number of patient–physician encounters by age group and condition, with observed antibiotic prescribing rate
| Condition | Patient age, yr; no. of encounters | Patient age, yr; antibiotic prescribing rate/% unnecessary* | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| < 2 | 2–18 | 19–64 | ≥ 65 | All ages | < 2 | 2–18 | 19–64 | ≥ 65 | All ages | |
| Common cold | 13 097 | 33 054 | 56 988 | 13 127 | 116 266 | 11.1/11.1 | 18.7/18.7 | 18.8/18.8 | 19.8/19.8 | 18.0/18.0 |
| Miscellaneous nonbacterial infections† | 7318 | 24 315 | 50 610 | 9758 | 92 001 | 34.8/34.8 | 23.5/23.5 | 8.4/8.4 | 6.7/6.7 | 14.3/14.3 |
| Urinary tract infection‡ | 371 | 4876 | 29 522 | 15 069 | 49 839 | 26.6/0.0 | 54.5/0.0 | 62.3/0.0 | 60.0/0.0 | 60.6/0.0 |
| Asthma | 658 | 6411 | 18 647 | 4975 | 30 691 | 7.1/7.1 | 5.5/5.5 | 7.9/7.9 | 11.1/11.1 | 7.9/7.9 |
| Acute bronchitis | 850 | 3007 | 15 588 | 7009 | 26 454 | 41.2/36.2 | 56.6/48.6 | 61.8/53.8 | 61.6/53.6 | 60.5/52.6 |
| Acute sinusitis | 148 | 1617 | 20 253 | 3899 | 25 917 | 53.4/33.4 | 61.0/41.0 | 68.1/50.1 | 61.6/43.6 | 66.6/48.4 |
| Gastroenteritis | 2231 | 4345 | 12 970 | 3939 | 23 485 | 1.7/0.0 | 3.0/0.0 | 7.6/2.6 | 6.9/1.9 | 6.0/1.7 |
| Purulent skin/ soft-tissue infection | 695 | 3492 | 20 253 | 3899 | 25 917 | 22.6 /0.0 | 30.9/0.0 | 24.3/0.0 | 25.6/0.0 | 25.5/0.0 |
| Eye infection | 1901 | 4207 | 10 927 | 2802 | 19 837 | 6.3/5.3 | 5.7/4.7 | 6.4/5.4 | 6.5/5.5 | 6.3/5.3 |
| Reproductive tract infection‡ | NA | 1311 | 12 894 | 1364 | 15 569 | NA | 14.7/0.0 | 17.3/0.0 | 11.5/0.0 | 16.6/0.0 |
| Acute pharyngitis | 495 | 7052 | 7329 | 364 | 15 240 | 74.6/56.6 | 77.4/37.4 | 63.6/35.6 | 44.0/16.0 | 69.9/36.7 |
| Nonpurulent skin/ soft-tissue infection‡ | 233 | 1477 | 8307 | 4517 | 14 534 | 51.9/0.0 | 64.7/0.0 | 67.2/0.0 | 64.6/0.0 | 65.9/0.0 |
| Pneumonia‡ | 553 | 2099 | 6306 | 4152 | 13 110 | 62.8/0.0 | 74.4/0.0 | 63.9/0.0 | 58.2/0.0 | 63.8/0.0 |
| Acute otitis media | 1974 | 4806 | NA | NA | 6888 | 71.6¶/31.6 | 73.4/43.4 | NA | NA | 61.6/39.3 |
| Influenza | 125 | 926 | 3838 | 1198 | 6087 | 16.8/16.8 | 13.2/13.2 | 10.5/10.5 | 6.8/6.8 | 10.3/10.3 |
| Otitis externa | 112 | 1338 | 2842 | 958 | 5250 | 38.4/38.4 | 16.2/16.2 | 13.2/12.2 | 8.6/7.6 | 13.7/12.9 |
| Dental condition | 232 | 873 | 2501 | 639 | 4245 | 2.2/0.0 | 11.5/7.5 | 46.7/42.7 | 37.7/33.7 | 35.7/31.8 |
| Acute exacerbation of COPD | NA | NA | 949 | 1604 | 2553 | NA | NA | 80.1/30.1 | 76.1/26.1 | 77.6/27.6 |
| Prostatitis | NA | NA | 1377 | 729 | 2106 | NA | NA | 46.9/0.0 | 30.6/0.0 | 41.3/0.0 |
| Miscellaneous bacterial infectionsठ| 40 | 257 | 1337 | 195 | 1829 | 32.5/0.0 | 17.1/0.0 | 6.4/0.0 | 8.7/0.0 | 8.7/0.0 |
| Epididymo-orchitis | NA | 88 | 1165 | 159 | 1412 | NA | 27.3 /0.0 | 46.2/0.0 | 59.8/0.0 | 46.4/0.0 |
| Chronic sinusitis | < 6 | < 100 | 1042 | 282 | 1387 | Sup | Sup | 21.9/7.9 | 21.6/7.6 | 21.4/7.5 |
| Pyelonephritis‡ | < 6 | < 100 | 735 | 177 | 986 | Sup | Sup | 60.5/0.0 | 59.9/0.0 | 59.9/0.0 |
| Total | 31 148 | 105 682 | 279 618 | 79 435 | 495 901** | 23.4/17.6 | 29.6/18.6 | 30.3/14.5 | 35.7/13.0 | 30.6/15.4 |
Note: COPD = chronic obstructive pulmonary disease, NA = not available, Sup = suppressed owing to small cell size.
↵* The percent unnecessary was calculated by subtracting the expected prescribing rate (Appendix 1, Supplemental Table S1) from the total antibiotic prescribing rate. Totals are weighted by the number of encounters. The conditions are ordered from the most to the least numbers of observed encounters.
↵† Included herpes simplex, herpes zoster, infectious mononucleosis, warts, other viral illnesses, ringworm, candidiasis, stomatitis and serous otitis media.
↵‡ Tier 1 conditions had unnecessary prescribing rates constrained to 0% since the expected appropriateness rates were 100% and we did not consider negative values to be inappropriate.
↵§ Included typhoid fever, tuberculosis, pertussis and septicemia.
↵¶ In children aged 6–24 months only. An additional 108 encounters in children less than 6 months of age were included, with an antibiotic prescribing rate of 50.9%, and all were considered appropriate.
↵** We excluded 3669 encounters involving conditions in patient age groups that did not have an expected prescribing rate (e.g., otitis media in adults).