Baseline characteristics in the different virus groups of the adult cohort
| Variable | Virus group (no. of healthcare episodes) | SARS-CoV-2 versus influenza | SARS-CoV-2 versus RSV | SARS-CoV-2 versus other viruses | ||||||
| SARS-CoV-2 | Influenza | RSV | Other viruses | OR (95% CI) | aOR (95% CI)* | OR (95% CI) | aOR (95% CI)* | OR (95% CI) | aOR (95% CI)* | |
| Baseline characteristics | ||||||||||
| Male sex, n (%) | 1010 (59) | 1194 (48) | 275 (44) | 840 (56) | 1.51 (1.34 to 1.71) | – | 1.80 (1.50 to 2.17) | – | 1.13 (0.98 to 1.30) | – |
| Age, median (IQR), years | 58 (42–71) | 68 (51–79) | 71 (60–81) | 61 (40–72) | – | – | – | – | – | – |
| Age categories, n (%) | ||||||||||
| 16–39 | 377 (22) | 401 (16) | 36 (6) | 376 (25) | 0.89 (0.72 to 1.09) | – | 2.34 (1.54 to 3.56) | – | 0.61 (0.49 to 0.76) | – |
| 40–49 | 212 (12) | 186 (8) | 33 (5) | 146 (10) | 1.07 (0.84 to 1.38) | – | 1.43 (0.92 to 2.23) | – | 0.88 (0.67 to 1.15) | – |
| 50–59 | 345 (20) | 325 (13) | 77 (12) | 209 (14) | 1.0 (ref) | – | 1.0 (ref) | – | 1.0 (ref) | – |
| 60–69 | 334 (19) | 404 (16) | 130 (21) | 285 (19) | 0.78 (0.63 to 0.96) | – | 0.57 (0.42 to 0.79) | – | 0.71 (0.56 to 0.90) | – |
| 70–79 | 209 (12) | 546 (22) | 167 (27) | 323 (21) | 0.36 (0.29 to 0.45) | – | 0.28 (0.20 to 0.38) | – | 0.39 (0.31 to 0.50) | – |
| ≥80 | 244 (14) | 606 (25) | 181 (29) | 169 (11) | 0.38 (0.31 to 0.47) | – | 0.30 (0.22 to 0.41) | – | 0.87 (0.67 to 1.14) | – |
| BMI, median (IQR), kg/m2§ | 27 (24–31) | 25 (22–29) | 25 (22–29) | 24 (21–28) | – | – | – | – | – | – |
| BMI categories, n (%) | ||||||||||
| Normoweight (18.5–24.9)† | 529 (31) | 1062 (43) | 276 (44) | 711 (47) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| Underweight (<18.5) | 44 (3) | 137 (6) | 39 (6) | 128 (9) | 0.65 (0.44 to 0.96) | 0.67 (0.45 to 1.01) | 0.58 (0.35 to 0.94) | 0.59 (0.35 to 1.01) | 0.46 (0.31 to 0.69) | 0.47 (0.31 to 0.69) |
| Overweight (25–29.9) | 638 (37) | 772 (31) | 176 (28) | 412 (27) | 1.66 (1.42 to 1.95) | 1.55 (1.31 to 1.83) | 1.89 (1.50 to 2.38) | 1.68 (1.31 to 2.15) | 2.08 (1.74 to 2.49) | 2.06 (1.71 to 2.47) |
| Obese (≥30) | 510 (30) | 497 (20) | 132 (21) | 257 (17) | 2.06 (1.74 to 2.45) | 1.91 (1.60 to 2.28) | 2.01 (1.56 to 2.59) | 1.67 (1.28 to 2.19) | 2.67 (2.19 to 3.27) | 2.66 (2.16 to 3.26) |
| CCI, median (IQR), points | 1 (0–2) | 1 (0–3) | 2 (1–4) | 2 (1–3) | – | – | – | – | – | – |
| CCI categories, n (%) | ||||||||||
| 0–1 | 1199 (70) | 1252 (51) | 235 (38) | 580 (38) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| 2–4 | 386 (22) | 890 (36) | 284 (46) | 675 (45) | 0.45 (0.39 to 0.52) | 0.52 (0.45 to 0.61) | 0.27 (0.22 to 0.33) | 0.39 (0.31 to 0.49) | 0.28 (0.24 to 0.32) | 0.24 (0.20 to 0.28) |
| ≥5 | 136 (8) | 326 (13) | 105 (17) | 253 (17) | 0.44 (0.35 to 0.54) | 0.50 (0.40 to 0.62) | 0.25 (0.19 to 0.34) | 0.36 (0.27 to 0.49) | 0.26 (0.21 to 0.33) | 0.22 (0.17 to 0.28) |
| ECI, median (IQR), points | 0 (0–6) | 5 (0–11) | 9 (3–14) | 7 (3–12) | – | – | – | – | – | – |
| ECI categories, n (%) | ||||||||||
| ≤0 | 947 (55) | 809 (33) | 104 (17) | 352 (23) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| 1–10 | 493 (29) | 1005 (41) | 255 (41) | 613 (41) | 0.42 (0.36 to 0.48) | 0.46 (0.40 to 0.54) | 0.21 (0.16 to 0.27) | 0.28 (0.21 to 0.36) | 0.30 (0.25 to 0.35) | 0.26 (0.21 to 0.31) |
| ≥11 | 281 (16) | 654 (26) | 265 (42) | 543 (36) | 0.37 (0.31 to 0.43) | 0.43 (0.36 to 0.52) | 0.12 (0.09 to 0.15) | 0.17 (0.13 to 0.23) | 0.19 (0.16 to 0.23) | 0.15 (0.12 to 0.18) |
| Comorbidities, n (%) | ||||||||||
| Diabetes mellitus‡ | 392 (23) | 467 (19) | 107 (17) | 247 (16) | 1.26 (1.09 to 1.47) | 1.46 (1.24 to 1.71) | 1.43 (1.13 to 1.81) | 1.87 (1.46 to 2.41) | 1.51 (1.26 to 1.80) | 1.54 (1.28 to 1.85) |
| Hypertension‡ | 660 (38) | 907 (37) | 246 (39) | 413 (27) | 1.07 (0.94 to 1.22) | 1.68 (1.44 to 1.95) | 0.96 (0.79 to 1.15) | 2.10 (1.69 to 2.63) | 1.65 (1.42 to 1.92) | 1.95 (1.64 to 2.32) |
| Cardiac disease‡ | 403 (23) | 728 (29) | 237 (38) | 410 (27) | 0.73 (0.63 to 0.84) | 1.01 (0.86 to 1.18) | 0.50 (0.41 to 0.61) | 0.85 (0.68 to 1.06) | 0.82 (0.70 to 0.96) | 0.80 (0.67 to 0.96) |
| Chronic pulmonary disease‡ | 252 (15) | 518 (21) | 171 (27) | 328 (22) | 0.65 (0.55 to 0.76) | 0.79 (0.67 to 0.94) | 0.45 (0.36 to 0.57) | 0.66 (0.52 to 0.84) | 0.62 (0.51 to 0.74) | 0.63 (0.52 to 0.75) |
| Chronic kidney failure‡ | 133 (8) | 259 (10) | 86 (14) | 159 (11) | 0.71 (0.57 to 0.89) | 0.84 (0.67 to 1.05) | 0.52 (0.39 to 0.70) | 0.74 (0.54 to 1.00) | 0.71 (0.56 to 0.90) | 0.70 (0.55 to 0.90) |
| Malignancy‡ | 185 (11) | 537 (22) | 218 (35) | 606 (40) | 0.43 (0.36 to 0.52) | 0.46 (0.39 to 0.56) | 0.22 (0.18 to 0.28) | 0.27 (0.21 to 0.34) | 0.18 (0.15 to 0.22) | 0.17 (0.14 to 0.21) |
| Immunosuppression‡ | 314 (18) | 791 (32) | 295 (47) | 807 (54) | 0.47 (0.41 to 0.55) | 0.50 (0.43 to 0.58) | 0.25 (0.20 to 0.30) | 0.30 (0.24 to 0.37) | 0.19 (0.17 to 0.23) | 0.18 (0.15 to 0.21) |
| Any of the comorbidities above‡ | 1014 (59) | 1754 (71) | 513 (82) | 1199 (80) | 0.58 (0.51 to 0.66) | 0.72 (0.61 to 0.83) | 0.31 (0.25 to 0.39) | 0.54 (0.42 to 0.70) | 0.37 (0.32 to 0.43) | 0.27 (0.23 to 0.33) |
Bold values indicate statistical significance.
*Analyses were adjusted for age and sex.
†Normoweight defined as a BMI of 18.5–24.9, underweight <18.5, overweight 25–29.9, obese ≥30.
‡Based on ICD-10 codes from −5 years to +24 hours from admission time point. See list of ICD-10 codes for each comorbidity category in online supplemental table 1.
§Variable containing missing values, which were imputed using multiple imputation by chained equations by predictive mean modelling. Descriptive data were calculated for each of the 50 imputed datasets, and the mean of each descriptive statistics is presented.
aOR, adjusted OR; BMI, body mass index; CCI, Charlson Comorbidity Index; ECI, Elixhauser Comorbidity Index; RSV, respiratory syncytial virus.