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.

SARS-CoV-2 has been associated with an increased rate of venous thromboembolism in critically ill patients. Since surgical patients are already at higher risk of venous thromboembolism than general populations, this study aimed to determine if patients with peri-operative or prior SARS-CoV-2 were at further increased risk of venous thromboembolism. We conducted a planned sub-study and analysis from an international, multicentre, prospective cohort study of elective and emergency patients undergoing surgery during October 2020. Patients from all surgical specialties were included. The primary outcome measure was venous thromboembolism (pulmonary embolism or deep vein thrombosis) within 30 days of surgery. SARS-CoV-2 diagnosis was defined as peri-operative (7 days before to 30 days after surgery); recent (1-6 weeks before surgery); previous (≥7 weeks before surgery); or none. Information on prophylaxis regimens or pre-operative anti-coagulation for baseline comorbidities was not available. Postoperative venous thromboembolism rate was 0.5% (666/123,591) in patients without SARS-CoV-2; 2.2% (50/2317) in patients with peri-operative SARS-CoV-2; 1.6% (15/953) in patients with recent SARS-CoV-2; and 1.0% (11/1148) in patients with previous SARS-CoV-2. After adjustment for confounding factors, patients with peri-operative (adjusted odds ratio 1.5 (95%CI 1.1-2.0)) and recent SARS-CoV-2 (1.9 (95%CI 1.2-3.3)) remained at higher risk of venous thromboembolism, with a borderline finding in previous SARS-CoV-2 (1.7 (95%CI 0.9-3.0)). Overall, venous thromboembolism was independently associated with 30-day mortality ). In patients with SARS-CoV-2, mortality without venous thromboembolism was 7.4% (319/4342) and with venous thromboembolism was 40.8% (31/76). Patients undergoing surgery with peri-operative or recent SARS-CoV-2 appear to be at increased risk of postoperative venous thromboembolism compared with patients with no history of SARS-CoV-2 infection. Optimal venous thromboembolism prophylaxis and treatment are unknown in this cohort of patients, and these data should be interpreted accordingly.

Circadian rhythms have an essential role in feeding behavior and metabolism. ROR␣ is a nuclear receptor involved in the interface of the circadian system and metabolism. The adipocyte glyceroneogenesis pathway derives free fatty acids (FFA) liberated by lipolysis to reesterification into triglycerides, thus regulating FFA homeostasis and fat mass. Glyceroneogenesis shares with hepatic gluconeogenesis the key enzyme phosphoenolpyruvate carboxykinase c (PEPCKc), whose gene is a ROR␣ target in the liver. ROR␣-deficient mice (staggerer, ROR sg/sg ) have been shown to exhibit a lean phenotype and fasting hypoglycemia for unsolved reasons. In the present study, we investigated whether adipocyte glyceroneogenesis might also be a target pathway of ROR␣, and we further evaluated the role of ROR␣ in hepatocyte gluconeogenesis. In vivo investigations comparing ROR sg/sg mice with their wild-type (WT) littermates under fasting conditions demonstrated that, in the absence of ROR␣, the release of FFA into the bloodstream was altered and the rise in glycemia in response to pyruvate reduced. The functional analysis of each pathway, performed in adipose tissue or liver explants, confirmed the impairment of adipocyte glyceroneogenesis and liver gluconeogenesis in the ROR sg/sg mice; these reductions of FFA reesterification or glucose production were associated with decreases in PEPCKc mRNA and protein levels. Treatment of explants with ROR␣ agonist or antagonist enhanced or inhibited these pathways, respectively, in tissues isolated from WT but not ROR sg/sg mice. Our results indicated that both adipocyte glyceroneogenesis and hepatocyte gluconeogenesis were regulated by ROR␣. This study demonstrates the physiological function of ROR␣ in regulating both glucose and FFA homeostasis. glyceroneogenesis; phosphoenolpyruvate carboxykinase c; nuclear retinoid-related orphan receptor-␣; adipose tissue RETINOID-RELATED ORPHAN RECEPTORS (RORs) are members of the nuclear receptor family. The ROR family comprises three members: ROR␣ (NR1F1), ROR␤ (NR1F2), and ROR␥ (NR1F3), with ROR␣ being the most abundant isoform present in the adipose tissue (18). RORs regulate gene transcription by binding to specific DNA response elements (RORE) consisting of the consensus RGGTCA core motif. Reciprocally, the nuclear receptor Rev-erb␣ (NR1D1) acts as a transcriptional repressor by competing with RORs for RORE binding and thereby antagonizes ROR action. Indeed, both receptors are often coexpressed in the same tissues (14).ROR␣ and Rev-erb␣ are involved in many pathways implicated in various physiological functions, including immune function, circadian rhythms, and metabolism. They appear to be pivotal players at the interface between the circadian system and metabolism (49). Among the direct target genes of ROR␣ and Rev-erb␣ are several clock genes such as Bmal1, thus ensuring a fine tuning of circadian rhythms, as well as some metabolic genes involved in the control of cholesterol and bile acid metabolism (11, 29) apolipoprotein synthesis (39), lipogene...