| No antibiotics, n (%) | Antibiotics, n (%) | Univariate analysis | Full model | |||
---|---|---|---|---|---|---|---|
OR (95% CI) | p-value | OR (95% CI) | p-value | ||||
 |  | 11,592 (20.1) | 44,706 (79.4) |  |  |  |  |
Demographic factors | |||||||
 Gender | Male | 4339 (37.4) | 18,589 (41.6) | 1 (ref) |  | 1 (ref) |  |
Female | 7253 (62.6) | 26,117 (58.4) | 0.84 (0.81, 0.88) | < 0.001 | 0.82 (0.76, 0.88) | < 0.001 | |
 Age at ALRTI (years) c | per SD |  |  | 0.90 (0.88, 0.92) | < 0.001 | 1.00 (0.96, 1.04) | 0.87 |
 IMD quintile | 1 (Least) | 2202 (19.0) | 9737 (21.8) | 1 (ref) |  | 1 (ref) |  |
2 | 2164 (18.7) | 9275 (20.8) | 0.95 (0.88, 1.02) | Â | 0.99 (0.88, 1.12) | Â | |
3 | 2257 (19.5) | 8824 (19.7) | 0.87 (0.81, 0.94) | Â | 0.94 (0.83, 1.05) | Â | |
4 | 2341 (20.2) | 8321 (18.6) | 0.79 (0.73, 0.85) | Â | 0.90 (0.80, 1.01) | Â | |
5 (Most) | 2628 (22.7) | 8549 (19.1) | 0.75 (0.69, 0.81) | < 0.001 | 1.01 (0.89, 1.15) | 0.21 | |
 Smoking status | Never | 4363 (37.6) | 17,652 (39.5) | 1 (ref) |  | 1 (ref) |  |
Current | 6220 (53.7) | 20,966 (46.9) | 0.84 (0.81, 0.88) | Â | 1.00 (0.93, 1.08) | Â | |
Previous | 1009 (8.7) | 6085 (13.6) | 1.51 (1.40, 1.63) | < 0.001 | 1.19 (1.05, 1.34) | 0.01 | |
Clinical factors | |||||||
 Season of infection | Summer | 4391 (37.9) | 15,994 (35.8) | 1 (ref) |  | 1 (ref) |  |
Winder | 7201 (62.1) | 28,712 (64.2) | 1.10 (1.05, 1.15) | < 0.001 | 1.06 (0.98, 1.14) | 0.14 | |
 Prescribed asthma medication d | No | 10,548 (91.0) | 37,436 (83.7) | 1 (ref) |  | 1 (ref) |  |
Yes | 1044 (9.0) | 7270 (16.3) | 2.11 (1.97, 2.27) | < 0.001 | 1.04 (0.94, 1.15) | 0.43 | |
 Number of ALRTI in prior 12 months | 0 | 7440 (64.2) | 42,027 (94.0) | 1 (ref) |  | 1 (ref) |  |
1 | 3131 (27.0) | 2318 (5.2) | 0.13 (0.12, 0.14) | Â | 0.24 (0.21, 0.27) | Â | |
2+ | 1021 (8.8) | 361 (0.8) | 0.06 (0.05, 0.07) | < 0.001 | 0.16 (0.13, 0.20) | < 0.001 | |
 Multimorbidity score e | 0 | 6998 (60.4) | 16,143 (36.1) | 1 (ref) |  | 1 (ref) |  |
1 | 1626 (14.0) | 11,484 (25.7) | 3.14 (2.96, 3.33) | Â | 1.15 (1.05, 1.27) | Â | |
2 | 1176 (10.1) | 7513 (16.8) | 2.87 (2.68, 3.08) | Â | 1.09 (0.97, 1.21) | Â | |
3+ | 1792 (15.5) | 9566 (21.4) | 2.45 (2.31, 2.60) | < 0.001 | 0.96 (0.86, 1.07) | < 0.001 | |
 Number of antibiotics prescribed in previous 12 months f | 0 | 8636 (74.5) | 532 (1.2) | 0.004 (0.003, 0.004) |  | 0.006 (0.005, 0.006) |  |
1 | 1584 (13.7) | 24,577 (55.0) | 1 (ref) | Â | 1 (ref) | Â | |
2 | 659 (5.7) | 10,163 (22.7) | 0.99 (0.90, 1.09) | Â | 1.16 (1.05, 1.28) | Â | |
3+ | 713 (6.2) | 9434 (21.1) | 0.86 (0.78, 0.94) | < 0.001 | 1.35 (1.21, 1.49) | < 0.001 | |
Practice factors | |||||||
 Practice ALRTI antibiotic rates (per 1000 patients) c | per SD |  |  | 1.47 (1.44, 1.5) | < 0.001 | 1.45 (1.39, 1.52) | < 0.001 |