Table 2 Baseline characteristics of the derivation and validation cohorts (i.e. incidental antibiotic users with no antibiotic prescription at the date of consultation and in previous 3 months)
| Â | CPRD LRTI | SAIL LRTI | CPRD URTI | SAIL URTI | CPRD UTI | SAIL UTI |
|---|---|---|---|---|---|---|
Total, N | 1,419,725 | 466,814 | 5,717,194 | 1,963,684 | 973,611 | 287,897 |
Males, N (%) | 628,695 (44.28) | 218,594 (46.83) | 2,423,833 (42.4) | 878,512 (44.74) | 132,359 (13.59) | 41,349 (14.37) |
Females, N (%) | 791,030 (55.72) | 248,220 (53.17) | 3,293,361 (57.6) | 1,085,172 (55.26) | 841,252 (86.41) | 246,458 (85.63) |
Median age, years | 53 | 42 | 33 | 16 | 52 | 41 |
Age category, N (%) | ||||||
 ≤ 5 years | 155,053 (10.92) | 107,097 (22.94) | 1,061,821 (18.57) | 628,694 (32.02) | 26,824 (2.76) | 18,273 (6.35) |
 6–18 | 91,898 (6.47) | 38,852 (8.32) | 1,012,710 (17.71) | 399,829 (20.36) | 69,958 (7.19) | 30,133 (10.47) |
 18–40 | 242,421 (17.08) | 80,786 (17.31) | 1,323,811 (23.15) | 432,553 (22.03) | 247,607 (25.43) | 93,602 (32.52) |
 41–60 | 377,157 (26.57) | 91,511 (19.6) | 1,174,640 (20.55) | 252,776 (12.87) | 240,361 (24.69) | 55,948 (19.22) |
 61–80 | 414,346 (29.18) | 102,210 (21.9) | 920,051 (16.09) | 188,988 (9.62) | 264,576 (27.17) | 55,318 (19.22) |
 Over 80 | 138,850 (9.78) | 46,358 (9.93) | 224,161 (3.92) | 60,844 (3.1) | 124,285 (12.77) | 34,533 (12) |
Ethnicity, N (%) | ||||||
 White and unknown | 1,376,529 (96.96) | 459,587 (98.45) | 5,420,768 (94.82) | 1,917,158 (97.63) | 954,772 (97.14) | 283,139 (98.38) |
 Combined minorities | 43,196 (3.04) | 7227 (1.55) | 296,426 (5.18) | 46,526 (2.37) | 27,839 (2.86) | 4668 (1.62) |
Charlson Comorbidity Index, N (%) | ||||||
 Very low | 747,870 (52.68) | 306,723 (65.71) | 3,973,455 (69.5) | 1,577,432 (80.33) | 576,725 (59.24) | 198,433 (68.95) |
 Low | 513,754 (36.19) | 123,116 (26.37) | 1,446,313 (25.3) | 323,548 (16.48) | 289,691 (29.75) | 65,104 (22.62) |
 Medium | 118,117 (8.32) | 27,325 (5.85) | 227,013 (3.97) | 47,483 (2.42) | 78,432 (8.06) | 17,459 (6.07) |
 High | 28,968 (2.04) | 7078 (1.52) | 51,882 (0.91) | 11,425 (0.58) | 20,807 (2.14) | 5028 (1.75) |
 Very high | 11,016 (0.78) | 2572 (0.55) | 18,531 (0.32) | 3796 (0.19) | 7956 (0.82) | 1783 (0.62) |
IMD quintile, N (%) | ||||||
 1—most affluent | 307,540 (21.66) | 112,734 (24.15) | 1,321,579 (23.12) | 456,651 (23.25) | 230,673 (23.69) | 58,126 (20.2) |
 2 | 312,919 (22.04) | 92,361 (19.79) | 1,289,612 (22.56) | 372,911 (18.99) | 234,671 (24.1) | 51,635 (17.94) |
 3 | 276,524 (19.48) | 95,484 (20.45) | 1,128,934 (19.75) | 378,739 (19.29) | 197,637 (20.3) | 57,876 (20.11) |
 4 | 271,090 (19.09) | 77,055 (16.51) | 1,078,634 (18.87) | 335,535 (17.09) | 174,247 (17.9) | 53,226 (18.49) |
 5—most deprived | 251,652 (17.73) | 89,180 (19.1) | 898,435 (15.71) | 419,848 (21.38) | 136,383 (14.01) | 66,944 (23.26) |