Anaesthesia 2021, 76, 748–758 doi:10.1111/anae.15458 Original Article Timing of surgery following SARS-CoV-2 infection: an international prospective cohort study COVIDSurg Collaborative* and GlobalSurg Collaborative* NIHR Global Health Research Unit on Global Surgery, Birmingham, UK Summary Peri-operative SARS-CoV-2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS-CoV-2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre-operative SARS-CoV-2 infection were compared with those without previous SARS-CoV-2 infection. The primary outcome measure was 30-day postoperative mortality. Logistic regression models were used to calculate adjusted 30-day mortality rates stratified by time from diagnosis of SARS-CoV-2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre-operative SARS-CoV-2 diagnosis. Adjusted 30-day mortality in patients without SARS-CoV-2 infection was 1.5% (95%CI 1.4–1.5). In patients with a pre-operative SARS-CoV-2 diagnosis, mortality was increased in patients having surgery within 0–2 weeks, 3–4 weeks and 5–6 weeks of the diagnosis (odds ratio (95%CI) 4.1 (3.3–4.8), 3.9 (2.6–5.1) and 3.6 (2.0–5.2), respectively). Surgery performed ≥ 7 weeks after SARS- CoV-2 diagnosis was associated with a similar mortality risk to baseline (odds ratio (95%CI) 1.5 (0.9–2.1)). After a ≥ 7 week delay in undertaking surgery following SARS-CoV-2 infection, patients with ongoing symptoms had a higher mortality than patients whose symptoms had resolved or who had been asymptomatic (6.0% (95%CI 3.2– 8.7) vs. 2.4% (95%CI 1.4–3.4) vs. 1.3% (95%CI 0.6–2.0), respectively). Where possible, surgery should be delayed for at least 7 weeks following SARS-CoV-2 infection. Patients with ongoing symptoms ≥ 7 weeks from diagnosis may benefit from further delay. ................................................................................................................................................................. Correspondence to: D. Nepogodiev Email: dnepogodiev@doctors.org.uk Accepted: 26 February 2021 Keywords: COVID-19; delay; SARS-CoV-2; surgery; timing This article is accompanied by an editorial by Wijeysundera and Khadaroo, Anaesthesia 2021; 76: 731–5. *Collaborating authors are listed in online Supporting Information Appendix S2. Twitter: @CovidSurg; @GlobalSurg Introduction SARS-CoV-2 case infection rates, but these countries Patients with peri-operative SARS-CoV-2 infection are at already have tens of millions of SARS-CoV-2 infection increased risk of death and pulmonary complications survivors. Most low- and middle-income countries (LMICs) following surgery [1–3]. As the cumulative number of are likely to have limited access to SARS-CoV-2 vaccines people who have had SARS-CoV-2 infection rises, it will be until at least 2023 [4, 5]. Thus, pre-operative SARS-CoV-2 increasingly common for patients needing surgery to have infection will remain a challenge for the foreseeable future. previously had SARS-CoV-2 infection. High-income Pre-pandemic studies suggest delaying surgery in countries that are already implementing vaccination patients who have experienced respiratory infection in the programmes are likely to experience reductions in new 4 weeks preceding surgery [6–8]. However, there is only 748 © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection Anaesthesia 2021, 76, 748–758 limited evidence regarding the optimal timing of surgery data in one or multiple surgical specialties, depending on following SARS-CoV-2 infection. A prospective cohort study local resources. Data could be collected over up to four including 122 patients having surgical for cancer, found that blocks of 7 consecutive days (5 October 2020 – 1 November surgery ≥ 4 weeks after a positive SARS-CoV-2 swab result 2020). was associated with a lower risk of postoperative mortality Patients were classified as having pre-operative SARS- than earlier surgery [9]. A study in Brazil included 49 patients CoV-2 infection based on any one of the following criteria: whose elective surgery was delayed following the (a) positive RT-PCR nasopharyngeal swab taken before pre-operative diagnosis of asymptomatic SARS-CoV-2 surgery (even if the result became available after surgery); infection [10]. These patients subsequently underwent (b) positive rapid antigen test performed before surgery; (c) surgery following confirmation of a negative SARS-CoV-2 chest computed tomography (CT) scan performed before reverse transcription polymerase chain reaction (RT-PCR) surgery showing changes consistent with pneumonitis nasopharyngeal swab result. The postoperative secondary to SARS-CoV-2 infection; (d) positive pre- complication rates were comparable to patients without operative immunoglobulin G or immunoglobulin M SARS-CoV-2 infection. However, the study did not assess the antibody test; or (e) clinical diagnosis made before surgery optimal duration of delay following SARS-CoV-2 diagnosis. (in the absence of negative RT-PCR swab results). Patients Clinical guidelines support postponing non-emergency who were diagnosed with SARS-CoV-2 in the period surgery for patients with pre-operative SARS-CoV-2 between postoperative days 0 and 30 were not studied. infection, but specific recommendations are conflicting, Data were captured on whether patients had experienced recommending delays ranging from 1 to 12 weeks [11–15]. SARS-CoV-2 symptoms, and if so, whether these symptoms More granular data are needed urgently to inform had resolved by the time of surgery. Both respiratory and clinical practice, especially regarding the significance of non-respiratory symptoms were considered. These were symptomatic vs. asymptomatic pre-operative SARS-CoV-2 classified as follows: asymptomatic; symptomatic but infection. The aim of this study was to determine the optimal symptoms now resolved; or symptomatic with ongoing timing of surgery following SARS-CoV-2 infection. symptoms. Time from the diagnosis of SARS-CoV-2 infection to day of surgery was collected as a categorical factor and Methods pre-determined to be analysed in the following categories: This was an international, multicentre, prospective cohort 0–2 weeks; 3–4 weeks; 5–6 weeks; and ≥ 7 weeks. study that included patients undergoing any type of The primary outcome measure was 30-day surgery. The study was registered at each participating postoperative mortality. Patients were followed-up either in- hospital in accordance with local and national regulations. person or by telephone, as soon after postoperative day 30 Informed patient consent was taken if required by local or as possible. If it was not possible to complete 30-day follow- national regulations. In the UK, this study was registered as up, in-patient mortality status was recorded. The secondary either a clinical audit or service evaluation at each recruiting outcome measure was the incidence of 30-day institution. Co-investigators were required to confirm that postoperative pulmonary complications. This was a applicable local and national approvals were in place composite of pneumonia, acute respiratory distress before uploading data to the online database. The study syndrome (ARDS) and/or unexpected postoperative was compliant with guidelines for the reporting of ventilation. Full definitions are available in online observational studies [16]. In the conduct of this study, no Supporting Information, Appendix S1. changes were made to usual patient care. Routine, The following information was collected for each anonymised data were collected using a secure online patient: age; sex; ASA physical status; revised cardiac risk database (REDCap, Vanderbilt University, Nashville, TN, USA). index (RCRI); presence of respiratory comorbidities; Participating hospitals included consecutive patients indication for surgery; grade of surgery (major/minor); and undergoing elective or emergency surgery for any surgical urgency (elective/emergency). For data protection indication in October 2020. Surgery was defined as any purposes, age was collected as a categorical variable. procedure that is routinely performed in an operating Consistent with previous analyses, age was categorised as theatre by a surgeon. A list of excluded procedures was < 70 years or ≥ 70 years [1, 2]. American Society of provided to investigators and is available in online Anesthesiologists physical status was classified as grades Supporting Information, Appendix S1. Before commencing 1–2 or grades 3–5. Patients were recorded as having data collection, hospitals defined which surgical specialties respiratory comorbidities if they had a diagnosis of asthma would be participating. Hospitals could choose to collect or chronic obstructive pulmonary disease (COPD). © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. 749 Anaesthesia 2021, 76, 748–758 COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection Indications for surgery were classified as: benign disease; CoV-2 infection or who were not infected. To address cancer; obstetrics; or trauma. Emergency surgery was further possible bias, average marginal effects were used to defined as surgery on an unplanned admission, and elective produce adjusted mortality rates by time from SARS-CoV-2 surgery was defined as surgery on a planned admission. The diagnosis to surgery, stratified by the following pre-selected RCRI calculation and grade of surgery classification are variables: age; ASA physical status; urgency of surgery; and available in online Supporting Information, Appendix S1. grade of surgery. In order to explore the association of pre- National income was recorded for each participating operative COVID-19 symptoms, a further logistic regression country, based on the World Bank’s classification [17]. model was fitted. This included only those patients who had To ensure consistent denominators, missing data were a pre-operative SARS-CoV-2 diagnosis, since COVID-19 included in the descriptive analyses. Imputation for missing symptom status was not applicable to patients who did not data was not planned as, based on previous studies, a < 2% have pre-operative SARS-CoV-2. These models were fitted rate of missing data was anticipated [1, 2]. For categorical with a primary outcome of 30-day postoperative mortality. variables, a chi-squared test was used to test for differences Further models were fitted for the secondary outcome of between groups. the incidence of 30-day postoperative pulmonary To adjust time from SARS-CoV-2 diagnosis to surgery for complications. Analyses were completed in Stata, version confounding factors, logistic regression models were fitted 15.1 (StataCorp, College Station, TX, USA). with variables selected a priori. These were variables that have previously been identified as independent predictors of Results mortality in patients with peri-operative SARS-CoV-2 infection A total of 140,231 patients were included across 1674 [1] and included: age; sex; ASA physical status; RCRI; hospitals in 116 countries (see online Supporting indication for surgery; grade of surgery; urgency of surgery; Information, Figure S1). Patient and surgical characteristics presence of respiratory comorbidities; and national income. are shown in Table 1. Baseline characteristic data for Average marginal effects were used to produce adjusted patients having elective surgery are available in online mortality estimates stratified by time from SARS-CoV-2 Supporting Information (Table S1). In total, 3127 (2.2%) diagnosis to surgery. The main model included all patients. patients had a pre-operative SARS-CoV-2 diagnosis. The Since delayed surgery is more likely for elective rather time from SARS-CoV-2 diagnosis to surgery was 0–2 weeks than emergency cases, a sensitivity analysis was performed in 1138 patients (36.4%), 3–4 weeks in 461 patients including only elective patients. A further sensitivity analysis (14.7%), 5–6 weeks in 326 patients (10.4%) and ≥ 7 weeks was performed including only patients who either had RT- in 1202 patients (38.4%) (Table 1). The majority of patients PCR nasopharyngeal swab-proven pre-operative SARS- were asymptomatic at the time of surgery (either having Table 1 Baseline characteristics and outcomes for patients undergoing surgery stratified by time from diagnosis of SARS-CoV-2 infection. Values are number (proportion). Pre-operative SARS-CoV-2 infection No pre-operative (by timing of diagnosis prior to surgery) SARS-CoV-2 infection 0–2 weeks 3–4 weeks 5–6 weeks ≥ 7 weeks (n = 137,104) (n = 1138) (n = 461) (n = 326) (n = 1202) Age; years 0–29 31,456 (22.9%) 331 (29.1%) 84 (18.2%) 62 (19.0%) 169 (14.1%) 30–49 37,673 (27.5%) 355 (31.2%) 149 (32.3%) 101 (31.0%) 364 (30.3%) 50–69 41,649 (30.4%) 265 (23.3%) 162 (35.1%) 109 (33.4%) 471 (39.2%) 70–79 17,577 (12.8%) 93 (8.2%) 52 (11.3%) 41 (12.6%) 121 (10.1%) ≥ 80 8747 (6.4%) 94 (8.3%) 14 (3.0%) 13 (4.0%) 77 (6.4%) Missing 2 (0%) – – – – Sex Female 71,375 (52.1%) 610 (53.6%) 220 (47.7%) 177 (54.3%) 634 (52.7%) Missing 5 (0.0%) – – – – (continued) 750 © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection Anaesthesia 2021, 76, 748–758 Table 1 (continued) Pre-operative SARS-CoV-2 infection No pre-operative (by timing of diagnosis prior to surgery) SARS-CoV-2 infection 0–2 weeks 3–4 weeks 5–6 weeks ≥ 7 weeks (n = 137,104) (n = 1138) (n = 461) (n = 326) (n = 1202) ASA physical status 1–2 103,503 (75.5%) 779 (68.5%) 316 (68.5%) 227 (69.6%) 805 (67.0%) 3–5 33,553 (24.5%) 359 (31.5%) 145 (31.5%) 99 (30.4%) 397 (33.0%) Missing 48 (0.0%) – – – – Revised cardiac risk index 0 61,379 (44.8%) 433 (38.0%) 176 (38.2%) 123 (37.7%) 446 (37.1%) 1 60,722 (44.3%) 512 (45.0%) 211 (45.8%) 145 (44.5%) 564 (46.9%) 2 11,116 (8.1%) 134 (11.8%) 50 (10.8%) 41 (12.6%) 129 (10.7%) ≥3 3818 (2.8%) 59 (5.2%) 24 (5.2%) 17 (5.2%) 62 (5.2%) Missing 69 (0.1%) – – – 1 (0.1%) Respiratory comorbidities Yes 12,190 (8.9%) 114 (10.0%) 45 (9.8%) 31 (9.5%) 123 (10.2%) Missing 111 (0.1%) – – – – Indication for surgery Benign 86,764 (63.3%) 629 (55.3%) 273 (59.2%) 208 (63.8%) 822 (68.4%) Cancer 23,612 (17.2%) 100 (8.8%) 117 (25.4%) 73 (22.4%) 234 (19.5%) Trauma 17,048 (12.4%) 193 (17.0%) 48 (10.4%) 27 (8.3%) 96 (8.0%) Obstetrics 9673 (7.1%) 216 (19.0%) 23 (5.0%) 18 (5.5%) 50 (4.2%) Missing 7 (0.0%) – – – – Grade of surgery Minor 55,301 (40.3%) 400 (35.1%) 131 (28.4%) 122 (37.4%) 462 (38.4%) Major 81,771 (59.6%) 738 (64.9%) 330 (71.6%) 204 (62.6%) 739 (61.5%) Missing 32 (0.0%) – – – 1 (0.1%) Urgency of surgery Elective 95,680 (69.8%) 338 (29.7%) 300 (65.1%) 232 (71.2%) 892 (74.2%) Emergency 41,413 (30.2%) 800 (70.3%) 161 (34.9%) 94 (28.8%) 310 (25.8%) Missing 11 (0.0%) – – – – COVID-19 symptoms Asymptomatic – 731 (64.2%) 203 (44.0%) 133 (40.8%) 317 (26.4%) Symptomatic – resolved – 124 (10.9%) 193 (41.9%) 163 (50.0%) 820 (68.2%) Symptomatic – ongoing – 277 (24.3%) 65 (14.1%) 28 (8.6%) 56 (4.7%) Missing – 6 (0.5%) - 2 (0.6%) 9 (0.7%) Country income High 90,024 (65.7%) 461 (40.5%) 159 (34.5%) 135 (41.4%) 696 (57.9%) Low/middle 47,080 (34.3%) 677 (59.5%) 302 (65.5%) 191 (58.6%) 506 (42.1%) 30-day postoperative mortality Yes 1973 (1.4%) 104 (9.1%) 32 (6.9%) 18 (5.5%) 24 (2.0%) Missing 92 (0.1%) 0 (0.0%) – – 2 (0.2%) 30-day postoperative pulmonary complications Yes 3654 (2.7%) 149 (13.1%) 60 (13.0%) 33 (10.1%) 42 (3.5%) Missing 105 (0.1%) – – – 3 (0.2%) ASA, American Society of Anaesthesiologists. © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. 751 Anaesthesia 2021, 76, 748–758 COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection Table 2 Unadjusted and adjusted model for 30-day postoperative mortality in all patients. Values are odds ratio (OR) (95%CI). Unadjusted Adjusted OR (95%CI) p value OR (95%CI) p value Age; years 0–69 Reference – Reference – ≥ 70 3.12 (2.86–3.40) < 0.001 1.72 (1.56–1.90) < 0.001 Sex Female Reference – Reference – Male 1.41 (1.29–1.53) < 0.001 1.09 (0.99–1.19) 0.068 ASA physical status 1–2 Reference – Reference – 3–5 8.96 (8.13–9.87) < 0.001 5.32 (4.75–5.96) < 0.001 Revised cardiac risk index 0 Reference – Reference – 1 2.33 (2.07–2.61) < 0.001 1.43 (1.26–1.63) < 0.001 2 6.50 (5.69–7.42) < 0.001 1.82 (1.56–2.13) < 0.001 ≥3 12.81 (11.02–14.89) < 0.001 2.78 (2.32–3.32) < 0.001 Respiratory comorbidities No Reference – Reference – Yes 1.71 (1.51–1.94) < 0.001 1.02 (0.89–1.16) 0.767 Indication for surgery Benign Reference – Reference – Cancer 1.62 (1.46–1.80) < 0.001 1.98 (1.76–2.23) < 0.001 Trauma 1.60 (1.43–1.80) < 0.001 0.91 (0.79–1.04) 0.173 Obstetrics 0.27 (0.19–0.37) < 0.001 0.23 (0.16–0.33) < 0.001 Grade of surgery Minor Reference – Reference – Major 3.25 (2.90–3.63) < 0.001 2.37 (2.11–2.67) < 0.001 Urgency of surgery Elective Reference – Reference – Emergency 5.60 (5.10–6.15) < 0.001 6.48 (5.83–7.21) < 0.001 Country income High Reference – Reference – Low/middle 1.76 (1.61–1.92) < 0.001 2.96 (2.69–3.26) < 0.001 Pre-operative SARS-CoV-2 by timing of pre-operative diagnosis No diagnosis Reference – Reference – 0–2 weeks 6.88 (5.60–8.46) < 0.001 3.22 (2.55–4.07) < 0.001 3–4 weeks 5.11 (3.56–7.33) < 0.001 3.03 (2.03–4.52) < 0.001 5–6 weeks 4.00 (2.48–6.45) < 0.001 2.78 (1.64–4.71) < 0.001 ≥ 7 weeks 1.40 (0.93–2.10) 0.107 1.02 (0.66–1.56) 0.940 ASA, American Society of Anesthesiologists. never had symptoms or symptoms having resolved) 64.2%; p < 0.001) and to undergo emergency surgery (Table 1). (30.2% vs. 43.7%; p < 0.001). However, there was lower Compared with patients who did not have SARS-CoV-2 proportion of patients aged ≥ 70 years in the cohort with infection, patients with pre-operative SARS-CoV-2 infection SARS-CoV-2 infection (16.1% vs. 19.2%; p < 0.001). were more likely to be ASA physical status 3–5 (24.5% vs. The overall 30-day postoperative mortality rate was 32.0%; p < 0.001), to undergo major surgery (59.6% vs. 1.5% (2151/140,231). When stratified by time from 752 © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection Anaesthesia 2021, 76, 748–758 SARS-CoV-2 diagnosis to surgery, 30-day postoperative mortality rate was similar to patients who did not have mortality rates were as follows: 9.1% (104/1138) 0–2 weeks; SARS-CoV-2 infection (Fig. 1). 6.9% (32/461) 3–4 weeks; 5.5% (18/326) 5–6 weeks; and Sensitivity analyses including only patients having 2.0% (24/1202) at ≥ 7 weeks. The 30-day mortality rate in elective surgery (available in online Supporting patients who did not have a pre-operative SARS-CoV-2 Information, Tables S1–S3) and only patients with RT-PCR infection was 1.4% (1973/137,104). nasopharyngeal swab-proven SARS-CoV-2 infection In the adjusted model, there was a significantly higher (available in online Supporting Information, Tables S4–S5) risk of 30-day mortality in patients with pre-operative SARS- showed that patients having surgery 0–2 weeks, 3–4 weeks CoV-2 infection diagnosed 0–2 weeks, 3–4 weeks and 5– and 5–6 weeks after SARS-CoV-2 diagnosis had 6 weeks before surgery compared with patients who did not significantly higher adjusted 30-day postoperative have a pre-operative SARS-CoV-2 infection (Table 2). mortality rates compared with patients who did not have However, there was no significant difference in 30-day SARS-CoV-2 infection (Fig. 1). Patients operated ≥ 7 weeks postoperative mortality rate in those patients diagnosed with after SARS-CoV-2 infection had a similar mortality as SARS-CoV-2 infection ≥ 7 weeks before surgery (Table 2). patients without SARS-CoV-2 infection. These findings were Adjusted 30-day mortality rate in patients who did also consistent across sub-groups stratified by age, ASA not have SARS-CoV-2 infection was 1.5% (95%CI 1.4– physical status, and grade and urgency of surgery (Fig. 2). 1.5). This was increased in patients who had surgery at In the analysis restricted to patients who had 0–2 weeks, 3–4 weeks and at 5–6 weeks after SARS-CoV- experienced pre-operative SARS-CoV-2 infection, patients 2 diagnosis (Fig. 1). In patients who had surgery with ongoing COVID-19 symptoms had a higher ≥ 7 weeks after SARS-CoV-2 diagnosis, the 30-day adjusted 30-day mortality rate than patients whose Figure 1 Overall adjusted 30-day postoperative mortality from main analysis and sensitivity analyses for patients having elective surgery and those patients with a reverse transcription polymerase chain reaction (RT-PCR) nasopharyngeal swab positive result for SARS-CoV-2. ‘No pre-operative SARS-CoV-2’ refers to patients without a diagnosis of SARS-CoV-2 infection. The time-periods relate to the timing of surgery following the diagnosis of SARS-CoV-2 infection. Sensitivity analysis for RT-PCR nasopharyngeal swab proven SARS-CoV-2 includes patients who either had RT-PCR nasopharyngeal swab proven SARS-CoV-2 or did not have a SARS-CoV-2 diagnosis; patients with a SARS-CoV-2 diagnosis which was not supported by a RT-PCR nasopharyngeal swab were not analysed. Full models and results are available in online Supporting Information (Appendix S1, Tables S3–S4 (elective patients), Tables S5–S6 (swab-proven SARS-CoV-2 infection)). © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. 753 Anaesthesia 2021, 76, 748–758 COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection Figure 2 Adjusted 30-day postoperative mortality rates from main analysis, stratified by pre-defined sub-groups. ‘No pre- operative SARS-CoV-2’ refers to patients without a diagnosis of SARS-CoV-2 infection. The time-periods relate to the timing of surgery following the diagnosis of SARS-CoV-2 infection. Full models and results are available in online Supporting Information (Appendix S1, Table S2). symptoms had resolved or who had been asymptomatic symptoms were at greatest risk of 30-day postoperative (Fig. 3). Following a ≥ 7-week delay between SARS-CoV-2 pulmonary complications (Fig. 5). infection and surgery, patients with ongoing COVID-19 symptoms had a higher mortality rate than patients whose Discussion symptoms had resolved or who had been asymptomatic This study found that patients operated within 6 weeks of (Fig. 3). SARS-CoV-2 diagnosis were at an increased risk of 30-day Overall, 2.8% (3938/140,231) of patients developed a postoperative mortality and 30-day postoperative postoperative pulmonary complication within 30 days, pulmonary complications. These risks decreased to including 1.7% (2387/140,231) who developed pneumonia, baseline in patients who underwent surgery ≥ 7 weeks after 0.8% (1100/140,231) who developed ARDS, and 0.8% SARS-CoV-2 diagnosis. These findings were consistent (1137/140,231) who had an unexpected requirement for across both low-risk (age < 70 years, ASA physical status mechanical ventilation. In both the overall analysis and the 1–2, minor surgery) and high-risk (age ≥ 70 years, ASA sensitivity analysis for elective surgery, patients who had physical status 3–5, major surgery) sub-groups. Therefore, surgery 0–2 weeks, 3–4 weeks and 5–6 weeks after SARS- surgery should be delayed for at least 7 weeks following CoV-2 diagnosis had significantly higher adjusted 30-day SARS-CoV-2 infection to reduce the risk of postoperative postoperative pulmonary complication rates compared mortality and pulmonary complications. In addition, we have with patients who did not have SARS-CoV-2 infection. shown that patients who are still symptomatic ≥ 7 weeks after However, patients who had surgery ≥ 7 weeks after SARS-CoV-2 infection and undergo surgery also have an SARS-CoV-2 infection had similar rates of postoperative increased mortality rate. As such, these patients may benefit pulmonary complications as patients without SARS-CoV-2 from a further delay until their symptoms resolve. infection (Fig. 4). Among patients operated ≥ 7 following Our findings that pre-operative SARS-CoV-2 infection SARS-CoV-2 diagnosis, those with ongoing COVID-19 increases the risk of postoperative mortality and pulmonary 754 © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection Anaesthesia 2021, 76, 748–758 Figure 3 Adjusted 30-day postoperative mortality rates in patients with pre-operative SARS-CoV-2 infection stratified by COVID-19 symptoms. The time-periods relate to the timing of surgery following the diagnosis of SARS-CoV-2 infection. Full models and results are available in online Supporting Information (Appendix S1, Tables S7–S8). Figure 4 Overall adjusted 30-day postoperative pulmonary complications (PPC) rate from main analysis and sensitivity analysis for patients having elective surgery. ‘No pre-operative SARS-CoV-2’ refers to patients without a diagnosis of SARS-CoV-2 infection. The time-periods relate to the timing of surgery following the diagnosis of SARS-CoV-2 infection. Full models and results are shown in online Supporting Information (Appendix S1, Tables S9–S10). © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. 755 Anaesthesia 2021, 76, 748–758 COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection Figure 5 Adjusted 30-day postoperative pulmonary complications (PPC) rate in patients with pre-operative SARS-CoV-2 infection stratified by COVID-19 symptoms. The time-periods relate to the timing of surgery following the diagnosis of SARS- CoV-2 infection. Full model and results are available in online Supporting Information (Appendix S1, Tables S13–S14). complications is line with previous work [1–3]. However, this support the safe restarting of surgery in the context of a is the first study to provide robust data regarding the rapidly increasing number of people who have survived optimal timing for surgery following SARS-CoV-2 infection. SARS-CoV-2. This study’s findings should support informed The greater granularity in this analysis compared with shared decision-making by anaesthetists, surgeons and previous studies [9, 10] has enabled ≥ 7 weeks to be patients. Decisions should be tailored for each patient, since determined as the optimal cut-off. Whilst cut-offs beyond the possible advantages of delaying surgery for at least 7 weeks were not formally tested, they are unlikely to offer a 7 weeks following SARS-CoV-2 diagnosis must be balanced significant advantage, since adjusted mortality rates for against the potential risks of delay. For some urgent surgical delay intervals ≥ 7 weeks were broadly stable (see online procedures, such as resection of advanced tumours [19, 20], Supporting Information, Appendix S1). Moreover, overall surgeons and patients may decide that the risks of delay are mortality following a delay of ≥ 7 weeks was similar to not justified. mortality in patients who did not have pre-operative SARS- This study has some limitations. Firstly, ascertainment of CoV-2 infection. SARS-CoV-2 status was based on routine pre-operative There is a backlog of tens of millions of elective tests. 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British Journal of Surgery 2020; surgery in 116 countries, in order to determine the optimal 107: e601–2. timing of surgery after SARS-CoV-2 infection. We found that 10. Baiocchi G, Aguiar S Jr, Duprat JP, et al. Early postoperative outcomes among patients with delayed surgeries after risks of postoperative morbidity and mortality are greatest if preoperative positive test for SARS-CoV-2: a case-control study patients are operated within 6 weeks of diagnosis of SARS- from a single institution. Journal of Surgical Oncology 2021; CoV-2 infection. Our results suggest that, where possible, 123: 823–33 11. Arnal Velasco S, Morales-Conde S. Recomendaciones para la surgery should be delayed for at least 7 weeks following programaci on de cirugıa en condiciones de seguridad durante SARS-CoV-2 infection. Patients with ongoing symptoms at la pandemia COVID-19. 2020. https://www.aecirujanos.es/file s/noticias/165/documentos/COVID19_Cirugia_electiva(1).pdf ≥ 7 weeks from diagnosis may benefit from further delay. (accessed 03/02/2021). 12. Andrea A, Stefano A, Francesco C, et al. Gestione della Fase Pre- Acknowledgements Operatoria. 2020. https://www.sicm.it/storage-file/covid19/ Trial registration at clinicaltrials.gov (NCT04509986). The 0525-LG-Pre-Op-Covid-SICM_PDF.pdf (accessed 05/02/2021). 13. Frydenberg M, Maddern G, Collinson T, et al. Delaying surgery authors would like to thank the RCS Covid Research Group for patients recovering from COVID-19: a rapid review for their support. Funding was provided by: the National commissioned by RACS. 2021. https://www.surgeons.org/-/ Institute for Health Research (NIHR) Global Health Research media/Project/RACS/surgeons-org/files/news/covid19-informa tion-hub/2021-01-11-RACS-Post-covid-delay-to-surgery-report. Unit; Association of Coloproctology of Great Britain and pdf (accessed 04/02/2021). Ireland; Bowel and Cancer Research; Bowel Disease 14. American Society of Anesthesiologists. ASA and APSF Joint Statement on Elective Surgery and Anesthesia for Patients after Research Foundation; Association of Upper Gastrointestinal COVID-19 Infection. 2020. https://www.asahq.org/about-asa/ Surgeons; British Association of Surgical Oncology; British newsroom/news-releases/2020/12/asa-and-apsf-joint-stateme Gynaecological Cancer Society; European Society of nt-on-elective-surgery-and-anesthesia-for-patients-after-covid- 19-infection (accessed 04/02/2021). Coloproctology; Medtronic; NIHR Academy; Sarcoma UK; 15. European Association for Endoscopic Surgery and other the Urology Foundation; Vascular Society for Great Britain Interventional Techniques. Preoperative testing and screening and Ireland; and Yorkshire Cancer Research. The views for elective surgery during the pandemic COVID-19 to re-start surgery. 2021. https://eaes.eu/covid-19-statements/preopera expressed are those of the authors and not necessarily those tive-testing-and-screening-for-elective-surgery-during-the-pa of the funding partners. No other competing interests. ndemic-covid-19-to-re-start-surgery/ (accessed 04/02/2021). © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists. 757 Anaesthesia 2021, 76, 748–758 COVIDSurg Collaborative and GlobalSurg Collaborative | Timing of surgery following SARS-CoV-2 infection 16. von Elm E, Altman DG, Egger M, et al. The strengthening the Table S7. Unadjusted and adjusted models for 30-day reporting of observational studies in epidemiology (STROBE) postoperative mortality in patients with pre-operative SARS- statement: guidelines for reporting observational studies. Lancet 2007; 370: 1453–7. CoV-2 infection. 17. World Bank. World Bank Country and Lending Groups. 2021. Table S8. Unadjusted and adjusted 30-day https://datahelpdesk.worldbank.org/knowledgebase/articles/ postoperative mortality in patients with pre-operative SARS- 906519-world-bank-country-and-lending-groups (accessed 04/01/2021). CoV-2 infection in key sub-groups. 18. COVIDSurg Collaborative. Elective surgery cancellations due Table S9. Unadjusted and adjusted model for 30-day to the COVID-19 pandemic: global predictive modelling to inform surgical recovery plans. British Journal of Surgery 2020; postoperative pulmonary complications in all patients. 107: 1440–9. Table S10. Unadjusted and adjusted 30-day 19. Hanna TP, King WD, Thibodeau S, et al. Mortality due to cancer postoperative pulmonary complications in key sub-groups treatment delay: systematic review and meta-analysis. British Medical Journal 2020; 371: m4087. from main analysis. 20. Maringe C, Spicer J, Morris M, et al. The impact of the COVID- Table S11. Sensitivity analysis for elective patients with 19 pandemic on cancer deaths due to delays in diagnosis in unadjusted and adjusted model for 30-day postoperative England, UK: a national, population-based, modelling study. Lancet Oncology 2020; 21: 1023–34. pulmonary complications. Table S12. Sensitivity analysis for elective patients with Supporting Information unadjusted and adjusted 30-day postoperative pulmonary Additional supporting information may be found online via complications in key sub-groups. the journal website. Table S13. Unadjusted and adjusted models for 30- day postoperative pulmonary complications in patients with Appendix S1. Supporting information. pre-operative SARS-CoV-2 infection. Table S1. Baseline characteristics and outcomes in Table S14. Unadjusted and adjusted 30-day elective patients. postoperative pulmonary complications in patients with Table S2. Unadjusted and adjusted 30-day pre-operative SARS-CoV-2 infection in key sub-groups. postoperative mortality (95%CI) in key sub-groups from Table S15. List of excluded procedures. main analysis. Table S16. 30-day postoperative mortality and Table S3. Sensitivity analysis for elective patients with postoperative pulmonary complication rates stratified by unadjusted and adjusted models for 30-day postoperative timing of surgery after SARS-CoV-2 diagnosis. mortality. Table S17. 30-day postoperative mortality and Table S4. Sensitivity analysis for elective patients with postoperative pulmonary complication rates in patients unadjusted and adjusted 30-day postoperative mortality operated ≥ 3 weeks after SARS-CoV-2 diagnosis, stratified by (95%CI) in key sub-groups. results of most recent repeat RT-PCR nasopharyngeal swab. Table S5. Sensitivity analysis for RT-PCR nasopharyngeal Figure S1. Study flowchart. swab proven SARS-CoV-2 infection, with unadjusted and Figure S2. Adjusted 30-day postoperative mortality adjusted models for 30-day postoperative mortality. rates from sensitivity analysis for elective patients, stratified Table S6. Sensitivity analysis for RT-PCR by pre-defined sub-groups. nasopharyngeal swab proven SARS-CoV-2 infection with Appendix S2. COVIDSurg Collaborative and unadjusted and adjusted 30-day postoperative mortality in GlobalSurg Collaborative authors (all PubMed indexed co- key sub-groups. authors). 758 © 2021 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists.