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Table 1 Basic characteristics of the individuals in the matched cohort for COVID-19 and seasonal influenza

From: COVID-19 and risk of subsequent life-threatening secondary infections: a matched cohort study in UK Biobank

Characteristics Matched cohort for COVID-19 Matched cohort for seasonal influenza
COVID-19 patients (N = 5151) Matched individuals& (N = 51,402) Seasonal influenza patients (N = 6169) Matched individuals& (N = 61,555)
Age at index date, years 66.00 (58.00–74.00) 66.00 (58.00–74.00) 62.00 (55.00–69.00) 62.00 (55.00–69.00)
Townsend deprivation index* − 1.46 (− 3.24–1.76) − 1.45 (− 3.22–1.75) − 1.49 (− 3.32–1.49) − 1.48 (− 3.32–1.49)
Charlson comorbidity index# 0.00 (0.00–2.00) 0.00 (0.00–2.00) 0.00 (0.00–1.00) 0.00 (0.00–1.00)
Follow-up time, weeks 11.86 (9.71–13.04) 12.71 (10.29–13.04) 13.04 (13.04–13.04) 13.04 (13.04–13.04)
Sex
Female 2564 (49.78%) 25,592 (49.79%) 3733 (60.51%) 37,289 (60.58%)
Male 2587 (50.22%) 25,810 (50.21%) 2436 (39.49%) 24,266 (39.42%)
Education level
College or university degree 1203 (23.35%) 16,330 (31.77%) 1813 (29.39%) 19,521 (31.71%)
A levels/AS levels or equivalent 476 (9.24%) 5710 (11.11%) 680 (11.02%) 6810 (11.06%)
O levels/GCSEs/CSEs or equivalent 1503 (29.18%) 14,080 (27.39%) 1700 (27.56%) 16,622 (27.00%)
Other qualifications 1838 (35.68%) 14,127 (27.48%) 1800 (29.18%) 17,228 (27.99%)
Unknown 131 (2.54%) 1155 (2.25%) 176 (2.85%) 1374 (2.23%)
Body mass index
< 24.1 964 (18.71%) 12,253 (23.84%) 1504 (24.38%) 15,608 (25.36%)
24.1–29.9 2503 (48.59%) 25,173 (48.97%) 3034 (49.18%) 29,810 (48.43%)
≥ 29.9 1640 (31.84%) 13,644 (26.54%) 1564 (25.35%) 15,742 (25.57%)
Unknown 44 (0.85%) 332 (0.65%) 67 (1.09%) 395 (0.64%)
Smoking
Yes 2491 (48.36%) 23,707 (46.12%) 2827 (45.83%) 27,336 (44.41%)
No 2621 (50.88%) 27,357 (53.22%) 3291 (53.35%) 33,831 (54.96%)
Unknown 39 (0.76%) 338 (0.66%) 51 (0.83%) 388 (0.63%)
History of life-threatening infections$
Yes 566 (10.99%) 3767 (7.33%) 366 (5.93%) 2589 (4.21%)
No 4585 (89.01%) 47,635 (92.67%) 5803 (94.07%) 58,966 (95.79%)
Life-threatening secondary infections diagnosis
Sepsis 119 (96.75%) 141 (93.38%) 69 (97.18%) 133 (97.08%)
Endocarditis 3 (2.44%) 6 (3.97%) 0 (0.00%) 2 (1.46%)
Central nervous system infections 1 (0.81%) 4 (2.65%) 2 (2.82%) 2 (1.46%)
  1. The values were reported as median (lower quantile-upper quantile) for continuous variables or number (%) for categorical variables; these variables were ascertained at the time of enrollment into the UK Biobank study: Townsend deprivation index, education level, BMI, and smoking
  2. Abbreviations: CSE, Certificate of Secondary Education; GCSE, General Certificate of Secondary Education
  3. *Townsend deprivation index was assigned to each individual based on their postcode location, and a greater index score implies a greater degree of deprivation
  4. #Charlson comorbidity index at the index date, calculated based on inpatient hospital data (see Additional File 1: Table S4 for details)
  5. &Up to 10 individuals free of exposure disease at the index date were randomly selected and individually matched to each exposed individual by birth year, sex, decile of Townsend deprivation index, and Charlson comorbidity index (0, 1, 2, or 3+)
  6. $Defined as hospital admission with any diagnosis of life-threatening infections prior to the index date