Table 1.
Baseline characteristics of paediatric cohort, aged < 18 years, in The Health Improvement Network® (THIN®) database, 1994–2015
| Characteristic | Control n = 1 809 029 |
Mild AD n = 381 678 |
Moderate AD n = 22 433 |
Severe AD n = 5320 |
|---|---|---|---|---|
| Age, median (IQR), years Sex | 4 (2–9) | 4 (1–8) | 9 (4–14) | 5 (1–10) |
| Sex | ||||
| Female | 872 279 (48·22) | 184 682 (48·39) | 11 054 (49·28) | 2335 (43·89) |
| Male | 936 750 (51·78) | 196 996 (51·61) | 11 379 (50·72) | 2985 (56·11) |
| Townsend deprivation index | ||||
| 1 Lowest | 424 409 (24·71) | 89 820 (24·89) | 4768 (22·55) | 1251 (25·00) |
| 2 Low | 340 677 (19·84) | 71 979 (19·95) | 4106 (19·42) | 1069 (21·37) |
| 3 Moderate | 355 559 (20·70) | 75 261 (20·86) | 4551 (21·52) | 1033 (20·65) |
| 4 High | 339 336 (19·76) | 70 649 (19·58) | 4316 (20·41) | 900 (17·99) |
| 5 Highest | 257 540 (14·99) | 53 113 (14·72) | 3407 (16·11) | 750 (14·99) |
| Unknown | 91 508 (5·06) | 20 856 (5·46) | 1285 (5·73) | 317 (5·96) |
| PY per 1000, median (IQR) | 4·99 (2·0–9·4) | 5·22 (2·1–9·7) | 6·02 (2·6–10·2) | 6·89 (2·7–12·6) |
| Allergic rhinitis | 75 050 (4·15) | 23 935 (6·27) | 2870 (12·79) | 521 (9·79) |
| Asthma | 169 679 (9·38) | 49 782 (13·04) | 6094 (27·17) | 1222 (22·97) |
| Congestive heart failure | 768 (0·04) | 134 (0·04) | 2 (0·01) | 5 (0·09) |
| Chronic kidney disease | 825 (0·05) | 140 (0·04) | 8 (0·04) | 19 (0·36) |
| COPD | 188 (0·01) | 47 (0·01) | 3 (0·01) | 3 (0·06) |
| Depression | 4318 (0·24) | 797 (0·21) | 158 (0·70) | 15 (0·28) |
| Diabetes mellitus | 2708 (0·15) | 395 (0·10) | 31 (0·14) | 8 (0·15) |
| Inflammatory bowel disease | 411 (0·02) | 65 (0·02) | 10 (0·04) | 79 (1·48) |
| Liver disease | 904 (0·05) | 165 (0·04) | 10 (0·04) | 21 (0·39) |
| Prior influenza vaccination | 33 292 (1·84) | 6484 (1·70) | 604 (2·69) | 121 (2·27) |
| Prior meningococcal vaccination | 35 889 (1·98) | 8134 (2·13) | 567 (2·53) | 117 (2·20) |
| Prior pneumococcal vaccination | 15 519 (0·86) | 3343 (0·88) | 112 (0·50) | 28 (0·53) |
| History of herpesvirus infectiona | 288 140 (15·93) | 64 421 (16·88) | 4484 (19·99) | 1062 (19·96) |
| History of opportunistic infectionb | 1045 (0·06) | 237 (0·06) | 29 (0·13) | 4 (0·08) |
| History of serious infectionc | 69 218 (3·83) | 15 919 (4·17) | 716 (3·19) | 221 (4·15) |
All values are n (%) unless stated otherwise. AD, atopic dermatitis; PY, person-years; IQR, interquartile range; COPD, chronic obstructive pulmonary disease.
Herpesvirus infection includes cytomegalovirus, Epstein–Barr virus, herpes simplex virus and varicella zoster virus infections.
Opportunistic infection includes actinomycosis/nocardiosis, aspergillosis, BK virus, cryptococcosis, cytomegalovirus, mucormycosis, other mycoses (blastomycosis, coccidioidomycosis, histoplasmosis and paracoccidioidomycosis), pneumocystis, progressive multifocal leukoencephalopathy, tuberculosis and toxoplasmosis.
Serious infection includes infections of respiratory tract, urinary tract, gastrointestinal tract/abdominal cavity, bone or joints, central nervous system or meninges, heart, skin or soft tissue, prostate, breast, and eyes and sepsis requiring hospitalization.