Table 1.
Investigating factors associated with viral infection using logistic regression
| Factor | Level | Summary* | Virus positive* | Virus negative* | Unadjusted OR (95% CI, P value)† | Adjusted OR (95% CI, P value)‡ |
|---|---|---|---|---|---|---|
| Time period | Pre-pandemic | 6296 (39) | 2090 (39) | 4206 (39) | Reference | Reference |
| Post-pandemic | 9961 (61) | 3315 (61) | 6646 (61) | 1·00 (0·94–1·07, P = 0·912) | 1·31 (1·22–1·41, P < 0·001) | |
| Season | Winter | 5016 (31) | 2001 (37) | 3015 (28) | Reference | Reference |
| Spring | 4305 (26) | 1541 (29) | 2764 (25) | 0·84 (0·77–0·91, P < 0·001) | 0·79 (0·73–0·87, P < 0·001) | |
| Summer | 2952 (18) | 667 (12) | 2285 (21) | 0·44 (0·40–0·49, P < 0·001) | 0·42 (0·38–0·47, P < 0·001) | |
| Autumn | 3984 (25) | 1196 (22) | 2788 (26) | 0·65 (0·59–0·71, P < 0·001) | 0·61 (0·56–0·67, P < 0·001) | |
| Age group (years) | < 1 | 1277 (13) | 959 (18) | 1218 (11) | Reference | Reference |
| 1–5 | 2596 (16) | 1327 (25) | 1269 (12) | 1·33 (1·18–1·49, P < 0·001) | 1·25 (1·11–1·41, P < 0·001) | |
| 6–16 | 1722 (11) | 564 (10) | 1158 (11) | 0·62 (0·54–0·71, P < 0·001) | 0·53 (0·46–0·60, P < 0·001) | |
| 17–45 | 3782 (23) | 1035 (19) | 2747 (25) | 0·48 (0·43–0·53, P < 0·001) | 0·36 (0·32–0·40, P < 0·001) | |
| 46–64 | 3247 (20) | 866 (16) | 2381 (22) | 0·46 (0·41–0·52, P < 0·001) | 0·37 (0·33–0·41, P < 0·001) | |
| ⩾65 | 2733 (17) | 654 (12) | 2079 (19) | 0·40 (0·35–0·45, P < 0·001) | 0·34 (0·30–0·39, P < 0·001) | |
| Gender | Female | 7941 (49) | 2575 (48) | 5366 (49) | Reference | Reference |
| Male | 8316 (51) | 5486 (52) | 2830 (51) | 1·07 (1·01–1·15, P = 0·03) | 1·08 (1·01–1·15, P = 0·032) | |
| Patients’ origin§ | GP | 3012 (19) | 1260 (23) | 1752 (16) | Reference | Reference |
| Hospital (general) | 11 878 (73) | 3725 (69) | 8153 (75) | 0·64 (0·59–0·69, P < 0·001) | 0·54 (0·49–0·59, P < 0·001) | |
| Hospital (critical care) | 1367 (8) | 420 (8) | 947 (9) | 0·62 (0·54–0·71, P < 0·001) | 0·56 (0·49–0·65, P < 0·001) |
OR, Odds ratio; CI, confidence interval.
*
Distribution of patient numbers, with corresponding % in parentheses, across factor levels for all patients (summary) and for virus-positive and virus-negative groups.
†
Unadjusted OR based on univariable logistic regression.
‡
Adjusted OR based on multivariable logistic regression.
§
Patients’ location corresponding with first clinical sample: GP, General Practitioner's surgery; Hospital (general), outpatients and non-critical-care patients; Hospital (critical care), patients admitted to an intensive care, intensive therapy, high dependency, or coronary care unit.