Comparing cefazolin/ metronidazole, piperacillin-tazobactam, or c efoxitin as surgical antibiotic prophylaxis in patients undergoing pancreaticoduodenectomy: A retrospective cohort study.

BACKGROUND: Preoperative antibiotic options for pancreaticoduodenectomy (PD) include cefoxitin (CX), piperacillin-tazobactam (PT), or combined cefazolin and metronidazole (CM). Recent studies suggest the superiority of PT over CX, but evidence for CM is unclear. OBJECTIVE: To explore the impact of preoperative antibiotic selection (CM vs. PT and CX vs. PT) on the development of surgical site infections (SSI). METHODS: Consecutive adult patients at one institution who underwent PD from November 2017 to December 2021 and received either CM, PT, or CX preoperatively, were included. The primary outcome was SSI. Secondary outcomes included postoperative infections and clinically significant postoperative pancreatic fistula (POPF). Logistic regression models were used. RESULTS: Among 127 patients included in the study, PT, CM, and CX were administered in 46 (36.2%), 44 (34.6%), and 37 (29.4%) patients, respectively. There were 32 (27.1%) SSI, 20 (36.1%) infections, and 21 (22.9%) POPF events. PT use was associated with reduced risk of SSI compared to CX (OR: 0.32, 95% CI: 0.11-0.89, p = 0.03), but there was no difference as compared to CM (OR: 0.75, 95% CI: 0.27-2.13, p = 0.59). There were no differences in secondary outcomes. CONCLUSION: PT reduced SSI rates compared to CX but was no different to CM among patients undergoing PD at our center.

Associations of preoperative anaemia with healthcare resource use and outcomes after colorectal surgery: a population-based cohort study.

BACKGROUND: Preoperative anaemia is common in patient undergoing colorectal surgery. Understanding the population-level costs of preoperative anaemia will inform development and evaluation of anaemia management at health system levels. METHODS: This was a population-based cohort study using linked, routinely collected data, including residents from Ontario, Canada, aged ≥18 yr who underwent an elective colorectal resection between 2012 and 2022. Primary exposure was preoperative anaemia (haemoglobin <130 g L-1 in males; <120 g L-1 in females). Primary outcome was 30-day costs in 2022 Canadian dollars (CAD), from the perspective of a publicly funded healthcare system. Secondary outcomes included red blood cell transfusion, major adverse events (MAEs), length of stay (LOS), days alive at home (DAH), and readmissions. RESULTS: We included 54,286 patients, with mean 65.3 (range 18-102) years of age and 49.0% females, among which 21 264 (39.2%) had preoperative anaemia. There was an absolute adjusted cost increase of $2671 per person at 30 days after surgery attributable to preoperative anaemia (ratio of means [RoM] 1.05, 95% confidence interval [CI] 1.04-1.06). Compared with the control group, 30-day risks of transfusion (odds ratio [OR] 4.34, 95% CI 4.04-4.66), MAEs (OR 1.14, 95% CI 1.03-1.27), LOS (RoM 1.08, 95% CI 1.07-1.10), and readmissions (OR 1.16, 95% CI 1.08-1.24) were higher in the anaemia group, with reduced DAH (RoM 0.95, 95% CI 0.95-0.96). CONCLUSIONS: Approximately $2671 CAD per person in 30-day health system costs are attributable to preoperative anaemia after colorectal surgery in Ontario, Canada.

Pilot and feasibility trials in surgery are incompletely reported according to the CONSORT checklist: a meta-research study.

OBJECTIVES: Given the key role that pilot and feasibility (PAF) trials play in addressing the challenges of surgical trials, adequate reporting completeness is essential. Our aim was to assess completeness of reporting and evaluate if the items of the Consolidated Standards of Reporting Trials (CONSORT) extension for PAF trials have been reported in surgical PAF trials. STUDY DESIGN: This is a metaresearch study reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were included if they were pilot or feasibility randomized trials evaluating a surgical intervention. The primary outcome was overall adherence to the CONSORT statement extension to randomized PAF trials checklist. A Poisson regression was performed to explore the association between research factors and reporting completeness. SETTING: MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched from January 1-December 31, 2011 and 2021. RESULTS: After screening 1991 citations, 38 studies from 2011 to 34 studies from 2021 were included. The mean CONSORT reporting score across all included studies was 21.5 (standard deviation 6.3). After excluding items that were not applicable to all studies, a mean of 20.1 (standard deviation 6.1) of 34 items (0.59) were reported. Studies published in 2021 (vs 2011) did not have a greater number of CONSORT items reported (incidence rate ratio [IRR] 1.01, 95% confidence interval [CI] 0.89-1.15). Studies registered in a clinical trial registry (IRR 1.29, 95% CI 1.12-1.48) and randomizing more than 50 patients (IRR 1.16, 95% CI 1.04-1.30) were associated with more CONSORT items reported. CONCLUSION: The reporting completeness of surgical PAF trials is poor and has not improved after the publication of the CONSORT extension.

Quality of life following perioperative optimization with nutritional supplements in patients undergoing gastrointestinal surgery for cancer: A randomized, placebo-controlled feasibility clinical trial.

BACKGROUND: Up to two thirds of patients presenting for abdominal cancer surgery are malnourished pre-operatively. Perioperative nutritional supplementation has been proposed to improve surgical outcomes, though its effect on quality of life (QoL) is not yet understood. METHODS: A randomized controlled feasibility trial for perioperative nutrition among patients undergoing major abdominal cancer surgery was conducted. Participants in the intervention group received supplements for 30 days before surgery. Participants completed two QoL questionnaires (EORTC-QLQ-C-30 and FACT-G) at baseline, then 4 and 12 weeks postoperatively. Participants were compared between and within groups at baseline, Weeks 4, and 12 using t tests. Minimal clinically important differences (MCIDs) were considered as a 10-point worsening from baseline. RESULTS: Sixty-six participants were available for analysis in this study, including 33 in the intervention and 30 in the control arms. Baseline demographics were balanced between groups except for different rates of pancreas cancer (36% intervention vs. 9% control) and colorectal cancer (19% intervention vs. 34% control). At baseline, participants in the intervention group had lower overall QoL (59% vs. 77%, p = 0.01), role functioning (72% vs 88%, p = 0.045), and cognitive functioning (79% vs 90%, p = 0.047). Following surgery, role and physical functioning worsened in the control group, without significant differences between groups. Role functioning was persistently worsened at 12 weeks in the control group. The rates of MCIDs were similar between both intervention and control groups. DISCUSSION: Perioperative nutrition was associated with preservation of QoL in the postoperative period following major abdominal cancer surgery compared to placebo. SUMMARY: Among patients undergoing surgery for cancer, the majority present at high risk for malnutrition. In this placebo-controlled randomized trial among patients undergoing major abdominal surgery for cancer, preoperative nutrition supplementation was associated with the preservation of QoL in the postoperative period.

Desmopressin to reduce periprocedural bleeding and transfusion: a systematic review and meta-analysis.

We systematically reviewed the literature to investigate the effects of peri-procedural desmopressin in patients without known inherited bleeding disorders undergoing surgery or other invasive procedures. We included 63 randomized trials (4163 participants) published up to February 1, 2023. Seven trials were published after a 2017 Cochrane systematic review on this topic. There were 38 trials in cardiac surgery, 22 in noncardiac surgery, and 3 in non-surgical procedures. Meta-analyses demonstrated that desmopressin likely does not reduce the risk of receiving a red blood cell transfusion (25 trials, risk ratio [RR] 0.95, 95% confidence interval [CI] 0.86 to 1.05) and may not reduce the risk of reoperation due to bleeding (22 trials, RR 0.75, 95% CI 0.47 to 1.19) when compared to placebo or usual care. However, we demonstrated significant reductions in number of units of red blood cells transfused (25 trials, mean difference -0.55 units, 95% CI - 0.94 to - 0.15), total volume of blood loss (33 trials, standardized mean difference - 0.40 standard deviations; 95% CI - 0.56 to - 0.23), and the risk of bleeding events (2 trials, RR 0.45, 95% CI 0.24 to 0.84). The certainty of evidence of these findings was generally low. Desmopressin increased the risk of clinically significant hypotension that required intervention (19 trials, RR 2.15, 95% CI 1.36 to 3.41). Limited evidence suggests that tranexamic acid is more effective than desmopressin in reducing transfusion risk (3 trials, RR 2.38 favoring tranexamic acid, 95% CI 1.06 to 5.39) and total volume of blood loss (3 trials, mean difference 391.7 mL favoring tranexamic acid, 95% CI - 93.3 to 876.7 mL). No trials directly informed the safety and hemostatic efficacy of desmopressin in advanced kidney disease. In conclusion, desmopressin likely reduces periprocedural blood loss and the number of units of blood transfused in small trials with methodologic limitations. However, the risk of hypotension needs to be mitigated. Large trials should evaluate desmopressin alongside tranexamic acid and enroll patients with advanced kidney disease.

Fragility of Statistically Significant Outcomes in Colonic Diverticular Disease Randomized Trials: A Systematic Review.

BACKGROUND: The p value has been criticized as an oversimplified determination of whether a treatment effect exists. One alternative is the fragility index. It is a representation of the minimum number of nonevents that would need to be converted to events to increase the p value above 0.05. OBJECTIVE: To determine the fragility index of randomized controlled trials assessing the efficacy of interventions for patients with diverticular disease since 2010 to assess the robustness of current evidence. DESIGN: MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched from inception to August 2022. SETTINGS: Articles were eligible for inclusion if they were randomized trials conducted between 2010 and 2022 with parallel, superiority designs evaluating interventions in patients with diverticular disease. Only randomized trials with dichotomous primary outcomes with an associated p value of <0.05 were considered for inclusion. PARTICIPANTS: Any surgical or medical intervention for patients with diverticular disease. MAIN OUTCOME MEASURES: The fragility index was determined by adding events and subtracting nonevents from the groups with the smaller number of events. Events were added until the p value exceeded 0.05. The smallest number of events required was considered the fragility index. RESULTS: After screening 1271 citations, 15 randomized trials met the inclusion criteria. Nine of the studies evaluated surgical interventions and 6 evaluated medical interventions. The mean number of patients randomly assigned and lost to follow-up per randomized controlled trial was 92 (SD 35.3) and 9 (SD 11.4), respectively. The median fragility index was 1 (range, 0-5). The fragility indices for the included studies did not correlate significantly with any study characteristics. LIMITATIONS: Small sample, heterogeneity, and lack of inclusion of studies with continuous outcomes. CONCLUSIONS: The randomized trials evaluating surgical and medical interventions for diverticular disease are not robust. Changing a single-outcome event in most studies was sufficient to make a statistically significant study finding not significant. See Video Abstract . FRAGILIDAD DE LOS RESULTADOS ESTADSTICAMENTE SIGNIFICATIVOS EN ENSAYOS ALEATORIOS DE ENFERMEDAD DIVERTICULAR DEL COLON UNA REVISIN SISTEMTICA: ANTECEDENTES:El valor p ha sido criticado por una determinación demasiado simplificada de si existe un efecto del tratamiento. Una alternativa es el Índice de Fragilidad. Es una representación del número mínimo de no eventos que deberían convertirse en eventos para aumentar el valor p por encima de 0,05.OBJETIVO:Determinar el IF de ensayos controlados aleatorios que evalúan la eficacia de las intervenciones para pacientes con enfermedad diverticular desde 2010 para evaluar la solidez de la evidencia actual.FUENTES DE DATOS:Se realizaron búsquedas en MEDLINE, Embase y CENTRAL desde el inicio hasta agosto de 2022.SELECCIÓN DE ESTUDIOS:Los artículos eran elegibles para su inclusión si eran ensayos aleatorizados realizados entre 2010 y 2022 con diseños paralelos de superioridad que evaluaran intervenciones en pacientes con enfermedad diverticular. Sólo se consideraron para su inclusión los ensayos aleatorizados con resultados primarios dicotómicos con un valor de p asociado menor que 0,05.INTERVENCIÓNES:Cualquier intervención quirúrgica o médica para pacientes con enfermedad diverticular.PRINCIPALES MEDIDAS DE VALORACIÓN:El índice de fragilidad se determinó sumando eventos y restando no eventos de los grupos con el menor número de eventos. Se agregaron eventos hasta que el valor p superó 0,05. El menor número de eventos requeridos se consideró índice de fragilidad.RESULTADOS:Después de examinar 1271 citas, 15 ensayos aleatorios cumplieron los criterios de inclusión. Nueve de los estudios evaluaron intervenciones quirúrgicas y seis evaluaron intervenciones médicas. El número medio de pacientes aleatorizados y perdidos durante el seguimiento por ECA fue 92 (DE 35,3) y 9 (DE 11,4), respectivamente. La mediana del índice de fragilidad fue 1 (rango: 0-5). Los índices de fragilidad de los estudios incluidos no se correlacionaron significativamente con ninguna característica del estudio.LIMITACIONES:Muestra pequeña, heterogeneidad y falta de inclusión de estudios con resultados continuos.CONCLUSIONES:Los ensayos aleatorios que evalúan las intervenciones quirúrgicas y médicas para la enfermedad diverticular no son sólidos. Cambiar un solo evento de resultado en la mayoría de los estudios fue suficiente para que un hallazgo estadísticamente significativo del estudio no fuera significativo. (Traducción- Dr. Ingrid Melo ).

Landiolol for the prevention of postoperative atrial fibrillation after cardiac surgery: a systematic review and meta-analysis.

PURPOSE: Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery. Although the evidence suggests that beta blockers prevent POAF, they often cause hypotension. Landiolol, an ultra-short-acting ß1 blocker, may prevent POAF, without adverse hemodynamic consequences. SOURCE: We searched MEDLINE, CENTRAL, Embase, and trial registries between January 1970 and March 2022. We included randomized controlled trials (RCTs) that evaluated the effect of landiolol for the prevention of POAF after cardiac surgery. Two reviewers independently assessed eligibility, extracted data, and assessed risk of bias using the Risk of Bias 2.0 tool. We pooled data using random-effects models. We used the Grading of Recommendations, Assessment, Development and Evaluations framework to assess certainty of evidence. PRINCIPAL FINDINGS: Nine RCTs including 868 participants met the eligibility criteria. Patients randomized to landiolol (56/460) had less POAF compared with controls (133/408) with a relative risk (RR) of 0.40 (95% confidence interval [CI], 0.30 to 0.54; I2 = 0%;) and an absolute risk of 12.2% vs 32.6% (absolute risk difference, 20.4%; 95% CI, 15.0 to 25.0). Landiolol resulted in a shorter hospital length-of-stay (LOS) (268 patients; mean difference, -2.32 days; 95% CI, -4.02 to -0.57; I2 = 0%). We found no significant difference in bradycardia (RR, 1.11; 95% CI, 0.48 to 2.56; I2 = 0%). No hypotension was reported with landiolol. We judged the certainty of evidence as moderate for POAF (because of indirectness as outcomes were not clearly defined) and low for LOS (because of imprecision and concern of reporting bias). CONCLUSION: In patients undergoing cardiac surgery, landiolol likely reduces POAF and may reduce LOS. A definitive large RCT is needed to confirm these findings. STUDY REGISTRATION: PROSPERO (CRD42021262703); registered 25 July 2021.

RéSUMé: OBJECTIF: La fibrillation auriculaire postopératoire (FAPO) est une complication fréquente après une chirurgie cardiaque. Bien que les données probantes suggèrent que les bêta-bloqueurs préviennent la FAPO, ces agents provoquent souvent une hypotension. Le landiolol, un ß1-bloqueur à action ultra-courte, pourrait prévenir la FAPO sans conséquences hémodynamiques indésirables. SOURCES: Nous avons effectué des recherches dans les bases de données MEDLINE, CENTRAL et Embase, et dans les registres d'études publiées entre janvier 1970 et mars 2022. Nous avons inclus les études randomisées contrôlées (ERC) évaluant l'effet du landiolol pour la prévention de la FAPO après une chirurgie cardiaque. Deux personnes ont indépendamment révisé l'éligibilité, extrait les données et évalué le risque de biais à l'aide de l'outil Risque de biais 2.0. Nous avons regroupé les données à l'aide de modèles à effets aléatoires. Nous avons utilisé le système de notation GRADE (Grading of Recommendations Assessment, Development, and Evaluation) pour évaluer la certitude des données probantes. CONSTATATIONS PRINCIPALES: Neuf ERC incluant 868 personnes remplissaient les critères d'éligibilité. Les patient·es randomisé·es dans le groupe landiolol (56/460) présentaient moins de FAPO que les témoins (133/408), avec un risque relatif (RR) de 0,40 (intervalle de confiance [IC] à 95 %, 0,30 à 0,54; I2 = 0 %) et un risque absolu de 12,2 % vs 32,6 % (différence de risque absolue, 20,4 %; IC 95 % 95 %, 15,0 à 25,0). Le landiolol a entraîné une durée de séjour hospitalier plus courte (268 patient·es; différence moyenne, −2,32 jours; IC 95 %, −4,02 à −0,57; I2 = 0 %). Nous n'avons trouvé aucune différence significative en matière de bradycardie (RR, 1,11; IC 95 %, 0,48 à 2,56; I2 = 0 %). Aucune hypotension n'a été rapportée avec le landiolol. Nous avons jugé que la certitude des données probantes était modérée pour la FAPO (en raison du caractère indirect car les critères d'évaluation n'étaient pas clairement définis) et faible pour la durée de séjour hospitalier (en raison de l'imprécision et de questionnements concernant le biais de déclaration). CONCLUSION: Chez les patient·es bénéficiant d'une chirurgie cardiaque, le landiolol réduit probablement la FAPO et peut réduire la durée de séjour hospitalier. Une ERC définitive à grande échelle est nécessaire pour confirmer ces résultats. ENREGISTREMENT DE L'éTUDE: PROSPERO (CRD42021262703); enregistrée le 25 juillet 2021.

The impact of surgical randomised controlled trials on the management of FAI syndrome: a citation analysis.

PURPOSE: To identify and assess the clinical impact of randomised controlled trials (RCTs) assessing the surgical management of femoroacetabular impingement syndrome (FAIS) through a citation analysis. METHODS: MEDLINE, EMBASE and CENTRAL were searched from inception to April 22, 2023 for RCTs assessing the surgical management of FAIS. Study characteristics were directly abstracted from included trials and citation metrics were obtained from the Clarivate Web of Knowledge database on May 19, 2023. The continuous fragility index (CFI) was calculated for eligible outcomes. Univariate regression models were used to explore correlations between total citations per year and various study characteristics. RESULTS: Ten studies comprising one thousand two hundred ninetypatients were eligible for analysis. Studies were published from 2013 to 2023. Eight countries were represented across various trials with 91% being either North American or European. The mean journal impact factor of published studies was 39.684 (median 2.982; range 1.31-202.73). The mean citation density was 14.17 (range 0.33-48.67). The median CFI was 4.8 (range 1-32.2). Correlation analysis demonstrated strong and statistically significant correlations to study sample size (R = 0.75, p = 0.012), journal impact factor (R = 0.80, p = 0.006) and continuous fragility index (R = 0.95, p = 0.015). CONCLUSION: Trials assessing the surgical management of FAIS present with a wide range of clinical uptake based on citation density and are published in journals of broadly variable impact factor. Despite promising citation metrics, high-quality evidence on arthroscopy for FAIS is limited to the United States and Europe with an unclear international impact. Future knowledge translation efforts are warranted to maximise the international uptake of evidence regarding arthroscopic management of FAIS. LEVEL OF EVIDENCE: I.

Laparoscopic ovarian transposition prior to pelvic radiation in young women with anorectal malignancies: a systematic review and meta-analysis of prevalence.

AIM: Young women undergoing radiotherapy (RT) for pelvic malignancies are at risk of developing premature ovarian insufficiency. Ovarian transposition (OT) aims to preserve ovarian function in these patients. However, its role in anorectal malignancy has yet to be firmly established. The aim of this review was to determine the effectiveness of laparoscopic OT in preserving ovarian function in premenopausal women undergoing neoadjuvant pelvic RT for anorectal malignancies. METHODS: MEDLINE, Embase and CENTRAL were systematically searched from inception through to May 2022. Articles were included if they evaluated ovarian function after OT in women with anorectal malignancies undergoing pelvic RT. The primary outcome was ovarian function preservation. The secondary outcome was 30-day postoperative morbidity following OT. RESULTS: From 207 citations, 10 studies with 133 patients with rectal or anal cancer who underwent OT prior to RT were included. Meta-analysis of pooled proportions of preserved ovarian function demonstrated an incidence of 66.9% (95% CI 55.0-79.0%, I2 = 43%). The 30-day postoperative morbidity rate was 1.2% (n = 1). There was heterogeneity in interventions and outcome reporting. CONCLUSIONS: Laparoscopic OT in premenopausal patients undergoing pelvic radiation for anorectal malignancies might be an effective technique at reducing ovarian exposure to RT. The meta-analyses must be interpreted within the context of clinical heterogeneity of the included studies. Further studies are required to fully investigate the outcomes of OT in patients undergoing pelvic radiation for anorectal malignancies.

Prognostic factors of overall survival in patients with recurrent disease following liver resection for colorectal cancer metastases: A multicenter external validation study.

BACKGROUND: The clinical course of patients experiencing recurrence following hepatectomy for colorectal cancer metastases (CRM) is poorly defined. Previous studies associated shorter time to recurrence (TTR) in months, node-positive primary tumor, and more than one site of recurrence with worse outcomes. METHODS: We conducted a retrospective cohort study across four Canadian institutions to externally validate previously established prognostic factors of overall survival (OS). We included consecutive adult patients who had a recurrence following curative-intent liver resection for CRM. Prognostic factors were explored using a multivariable Cox regression model. Risk group cutoffs were identified through recursive partitioning. OS between low- and high-risk groups was compared using the Kaplan-Meier method. RESULTS: This study included 471 patients. Shorter TTR in months (hazard ratio [HR]: 0.95, 95% confidence interval [CI]: 0.93-0.97), presence of extrahepatic disease at first hepatectomy (HR: 2.54, 95% CI: 1.18-5.50), and larger tumor size in millimetres (HR: 1.01, 95% CI: 1.00-1.02) were associated with worse OS. Median OS in the high- and low-risk groups were 40.5 (95% CI: 34.0-45.7 months) versus 64.7 months (95% CI: 57.9-72.3 months; p < 0.001), respectively. CONCLUSIONS: We externally validated the prognostic significance of shorter TTR (<8.5 months) as a predictor of worse OS in patients who recur the following hepatectomy for CRM.

Passive Versus Active Intra-Abdominal Drainage Following Pancreatic Resection: Does A Superior Drainage System Exist? A Systematic Review and Meta-Analysis.

Postoperative pancreatic fistula (POPF) is a major source of morbidity following pancreatic resection. Surgically placed drains under suction or gravity are routinely used to help mitigate the complications associated with POPF. Controversy exists as to whether one of these drain management strategies is superior. The objective was to identify and compare the incidence of POPF, adverse events, and resource utilization associated with passive gravity (PG) versus active suction (AS) drainage following pancreatic resection. MEDLINE, EMBASE, CINAHL, and Cochrane Library databases were searched from inception to May 18, 2020. Outcomes of interest included POPF, post-pancreatectomy hemorrhage (PPH), surgical site infection (SSI), other major morbidity, and resource utilization. Descriptive qualitative and pooled quantitative meta-analyses were performed. One randomized control trial and five cohort studies involving 10 663 patients were included. Meta-analysis found no difference in the odds of developing POPF between AS and PG (p = 0.78). There were no differences in other endpoints including PPH (p = 0.58), SSI (wound p = 0.21, organ space p = 0.05), major morbidity (p = 0.71), or resource utilization (p = 0.72). The risk of POPF or other adverse outcomes is not impacted by drain management following pancreatic resection. Based on current evidence, a suggestion cannot be made to support the use of one drain over another at this time. There is a trend toward increased intra-abdominal wound infections with AS drains (p = 0.05) that merits further investigation.

The Impact of Bariatric Surgery on Diabetic Retinopathy: A Systematic Review and Meta-Analysis.

OBJECTIVE: While bariatric surgery induces remission of type 2 diabetes mellitus and reduces other microvascular complications, its impact on diabetic retinopathy (DR) is unclear. Some trials suggest early worsening of DR postsurgery because of rapid improvements in hyperglycemia. This meta-analysis sought to estimate the impact of bariatric surgery on DR for obese patients compared with medical treatment. DESIGN: Systematic review and meta-analysis. METHODS: The Medline, Embase, and PubMed Central databases were searched to March 2020. Primary studies comparing DR in patients undergoing bariatric surgery with those undergoing medical management were included. Results were meta-analyzed using a random-effects model. Primary outcomes included prevalence of all DR and sight-threatening DR after surgery. Secondary outcomes included worsening of DR within and beyond 12 months. RESULTS: Overall, 14 studies comprised of 110,300 surgical patients and 252,289 control subjects were included. Surgical patients had a statistically significantly lower postoperative prevalence of all DR (relative risk [RR] 0.17 [95% confidence interval {CI} 0.13-0.22]) and sight-threatening DR (RR 0.47 [95% CI 0.27-0.82]). Early worsening of DR and progression to sight-threatening DR had occurred more often in those with more severe DR initially. However, beyond 12 months, bariatric surgery resulted in significantly fewer patients with worsened DR (RR 0.29 [95% CI 0.16-0.54]). The overall risk of bias was low; estimates of relative effects had low to moderate certainty of evidence. CONCLUSION: While bariatric surgery was associated with fewer cases of all and sight-threatening DR, early worsening was more severe in patients with existing sight-threatening DR. These findings argue for frequent monitoring during the first postoperative year.