Stratification analysis of association between preoperative COVID-19 and risk of postoperative complications
| Subgroup | No COVID-19 | Pre-1w | Pre-2w | Pre-3w | Pre-4w or more |
| Age | |||||
| <50 (n=1247) | Ref. | 1.78 (0.59, 5.32) | 0.99 (0.31, 3.23) | 0.90 (0.29, 2.73) | 0.82 (0.46, 1.47) |
| ≥50 (n=1583) | Ref. | 3.34 (1.67, 6.70) | 2.65 (1.36, 5.16) | 1.46 (0.67, 3.18) | 1.43 (1.00, 2.03) |
| Smoking | |||||
| No (n=2484) | Ref. | 2.06 (1.07, 3.97) | 2.31 (1.25, 4.25) | 1.20 (0.60, 2.42) | 1.12 (0.81, 1.55) |
| Yes (n=346) | Ref. | 17.22 (3.87, 76.70) | 1.65 (0.27, 10.03) | 2.52 (0.51, 12.53) | 2.54 (1.05, 6.15) |
| COVID-19 vaccination status | |||||
| No (n=221) | Ref. | 2.97 (0.20, 44.55) | 1.66 (0.08, 33.08) | 1.94 (0.20, 18.96) | 1.31 (0.51, 3.38) |
| Yes (n=2609) | Ref. | 2.68 (1.47, 4.88) | 2.14 (1.18, 3.89) | 1.21 (0.62, 2.38) | 1.24 (0.90, 1.71) |
| Comorbidity | |||||
| 0 (n=1825) | Ref. | 1.48 (0.46, 4.71) | 2.60 (1.10, 6.12) | 1.72 (0.60, 4.90) | 1.47 (0.83, 2.59) |
| ≥1 (n=1005) | Ref. | 3.66 (1.80, 7.42) | 2.03 (0.92, 4.47) | 1.06 (0.48, 2.36) | 1.17 (0.82, 1.66) |
| Severity of COVID-19 | |||||
| Mild (n=2728) | Ref. | 2.04 (1.02, 4.07) | 1.88 (1.01, 3.50) | 1.18 (0.59, 2.34) | 1.29 (0.95, 1.77) |
| Moderate/severe (n=1061) | Ref. | 5.92 (2.04, 17.18) | 5.12 (1.11, 23.67) | 2.40 (0.48, 12.09) | 0.68 (0.29, 1.61) |
Pre-1w, preoperative COVID-19 within 1 week; Pre-2w, preoperative COVID-19 within 1–2 weeks; Pre-3w, preoperative COVID-19 within 2–3 weeks; Pre-4w or more, preoperative COVID-19 beyond 3 weeks.
Values are odds ratios (ORs) with 95% confidence intervals (CIs), estimated from multivariable logistic regression models adjusted for age (continuous) and sex (men and women), BMI (continuous), smoking (yes or no), COVID-19 vaccination status (yes or no), comorbidities (yes or no), history of cancer (yes or no), ASA classification (grades 1–2 and grades 3–5), grade of surgery (minor or major), urgency of surgery (elective or emergency), duration of surgery (≤240 min or >240 min), general anaesthesia (yes or no) and type of surgery (thoracic, head and neck, cardiovascular, digestive, breast, gynaecologic and obstetrics, orthopaedic and other surgeries).
ASA, American Society of Anesthesiologists; BMI, body mass index.