Serum copper and obesity among healthy adults in the National Health and Nutrition Examination Survey.

BACKGROUND: Copper (Cu) homeostasis are important processes in the cause of metabolic diseases, but the association between Cu and obesity remains unclear. METHODS: Participants were drawn from the 2011-2016 National Health and Nutrition Examination Survey (NHANES). Weighted logistic regression assessed the associations of serum Cu concentrations (tertiles) with obesity and central obesity in individuals without comorbidities. Obesity was defined as a BMI ≥30.0 kg/m2, and central obesity was defined as a waist circumference ≥80 cm for women and ≥95 cm for men. RESULTS: This cross-sectional study included 1,665 adults without comorbidities, representing 24,744,034 people (mean age 35.1 years, 48.5% female). High serum Cu levels (tertile 3: ≥19.19 µmol/L) were associated with higher odds of obesity (adjusted odds ratio [OR]: 4.48, 95% CI[confidence interval]: 2.44-8.32) and central obesity (OR: 2.36, 95% CI: 1.19-4.66) compared to low serum Cu levels (tertile 1: ≤15.64 µmol/L). The dose-response curve showed a nonlinear association between Cu levels and obesity (P-nonlinear = 0.02) and a linear association with central obesity (P-nonlinear = 0.21). CONCLUSION: This study suggests that higher serum Cu levels are associated with increased odds of obesity in healthy American adults.

First-line treatment with sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide-1 receptor agonists in type 2 diabetic population at low risk of cardiovascular disease: a meta-analysis.

Background: The benefit of first-line use of sodium-dependent glucose transport 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) in type 2 diabetes mellitus (T2DM) with low risk of cardiovascular diseases are not clear. Methods: PubMed, EMBASE and Cochrane Library databases were searched to identify eligible randomized controlled trials. We used the odds ratio (OR) and mean difference (MD) and the corresponding 95% confidence interval (CI) to assess the dichotomous and continuous variable, respectively. Results: Thirteen studies involving 2,885 T2DM at low risk of cardiovascular diseases were included. Compared to placebo, first line use of SGLT2i significantly reduced glycosylated hemoglobin type A1C (HbA1c) (MD: -0.72), weight (MD: -1.32) and fasting plasma glucose (FPG) (MD: -27.05) levels. Compared with metformin, SGLT2i reduced body weight (MD: -1.50) and FPG (MD: -10.13) more effectively, with similar reduction for HbA1c (MD: -0.05). No significant increased safety adverse was found for SGLT2i, including nasopharyngitis (OR: 1.07), urinary tract infection (OR: 2.31), diarrhea (OR: 1.18) and hypoglycemia (OR: 1.06). GLP-1RAs significantly reduced HbA1c (MD: -1.13), weight (MD: -2.12) and FPG (MD: -31.44) levels as first-line therapy compared to placebo. GLP-1RAs significantly increased occurrence of diarrhea (OR: 2.18), hypoglycemia (OR: 3.10), vomiting (OR: 8.22), and nausea (OR: 4.41). Conclusion: First line use of SGLT2i and GLP-1RAs is effective in reducing HbA1c, weight, and FPG levels in T2DM patients at low risk for cardiovascular disease. SGLT2i may be superior to metformin in controlling body weight and FPG. GLP-1RAs may increase the occurrence of diarrhea, hypoglycemia, vomiting, and nausea. Systematic review registration: PROSPERO (International Prospective Register of Systematic Reviews. https://www.york.ac.uk/inst/crd, CRD42022347233).

Association of serum copper (Cu) with cardiovascular mortality and all-cause mortality in a general population: a prospective cohort study.

BACKGROUND: Copper (Cu) homeostasis and Cu-induced cell death are gaining recognition as crucial processes in the pathogenesis of cardiovascular disease (CVD). Circulating Cu associated with CVD and mortality is yet to be fully elucidated. OBJECTIVE: This national prospective cohort study is to estimate relationship between serum Cu and the risk of CVD and all-cause mortality. METHODS: This study included participants from the National Health and Nutrition Examination Survey 2011-2016. Weighted Cox proportional hazards regression analysis and exposure-response curves were applied. RESULTS: This included 5,412 adults, representing 76,479,702 individuals. During a mean of 5.85 years of follow-up (31,653 person-years), 96 CVD and 356 all-cause mortality events occurred. Age and sex-adjusted survival curves showed that individuals with higher levels of serum Cu experienced increased CVD and all-cause death rates (tertiles, p < 0.05). Compared with the participant in tertile 1 of serum Cu (< 16.31 mol/L), those in tertile 3 (≥ 19.84 mol/L) were significantly associated with CVD mortality (HR: 7.06, 95%CI: 1.85,26.96), and all-cause mortality (HR: 2.84, 95% CI: 1.66,4.87). The dose-response curve indicated a linear relationship between serum Cu and CVD mortality (p -nonlinear = 0.48) and all-cause (p -nonlinear = 0.62). A meta-analysis included additional three prospective cohorts with 13,189 patients confirmed the association between higher serum Cu and CVD (HR: 2.08, 95% CI: 1.63,2.65) and all-cause mortality (HR: 1.89, 95%CI: 1.58,2.25). CONCLUSION: The present study suggests excessive serum Cu concentrations are associated with the risk of CVD and all-cause mortality in American adults. Our findings and the causal relationships require further investigation.

Sex differences in mortality and hospitalization in heart failure with preserved and mid-range ejection fraction: a systematic review and meta-analysis of cohort studies.

Introduction: The influence of sex on the prognosis of heart failure with preserved or intermediate ejection fraction (HFpEF and HFmrEF) remains uncertain. This study aimed to investigate whether sex differences impact the prognosis of patients diagnosed with HFpEF and HFmrEF. Methods: A comprehensive search across three databases (PubMed, the Cochrane Library, and Embase) was conducted to identify sex-related prognostic cohort studies focusing on HFpEF and HFmrEF. Risk estimates were synthesized using the random effects model. The analysis included 14 cohorts comprising 41,508 HFpEF patients (44.65% males) and 10,692 HFmrEF patients (61.79% males). Results: Among HFpEF patients, men exhibited significantly higher rates of all-cause mortality (13 studies; hazard ratio (HR): 1.24, 95% confidence interval (CI): 1.15 to 1.33)) and cardiovascular disease mortality (5 studies; HR: 1.22, 95% CI: 1.14 to 1.31) compared to women. However, no significant difference was observed in HF admissions. For HFmrEF patients, men displayed notably higher all-cause mortality (HR: 1.21, 95% CI: 1.12 to 1.31) but no significant differences in cardiovascular mortality or HF admissions. Discussion: These findings suggest that male patients diagnosed with HFpEF and HFmrEF may face a more unfavorable prognosis in terms of all-cause mortality. Variations were noted in cardiovascular mortality and HF admissions, indicating potential complexities in sex-related prognostic factors within these heart failure categories. In summary, male patients with HFpEF and HFmrEF may have a more unfavorable prognosis.

Fibroblast growth factor-23 and the risk of cardiovascular diseases and mortality in the general population: A systematic review and dose-response meta-analysis.

Background: In the past decade, fibroblast growth factor 23 (FGF23) has been recognized as an important biomarker of cardiovascular diseases. This study aimed to assess the relationship between FGF23 and the risk of cardiovascular diseases (CVDs) in general populations. Methods: The protocol was registered prospectively in PROSPERO (CRD42021281837) and two authors independently searched for relevant studies in the PubMed, EMBASE, and Cochrane Library databases. The random effects model was applied. Results: In total, 29 prospective studies involving 135,576 participants were included. In the general population, the category analysis revealed that elevated FGF23 levels were related to increased risks of myocardial infarction (MI) (RR: 1.40, 95%CI: 1.03-1.89), stroke (RR: 1.20, 95%CI: 1.02-1.43), heart failure (HF) (RR: 1.37, 95%CI: 1.23-1.52), CVD events (RR: 1.22, 95%CI: 0.99-1.51), cardiovascular mortality (RR: 1.46, 95%CI: 1.29-1.65), and all-cause mortality (RR: 1.50, 95%CI: 1.29-1.74). In the continuous analysis, per doubling of FGF23 was associated with increased risks of MI (RR: 1.08, 95%CI: 0.94-1.25), stroke (RR: 1.21, 95%CI: 0.99-1.48), HF (RR: 1.24, 95%CI: 1.14-1.35), CVD events (RR: 1.12, 95%CI: 0.99-1.27), cardiovascular mortality (RR: 1.43, 95%CI: 1.09-1.88), all-cause mortality (RR: 1.37, 95%CI: 1.15-1.62). Furthermore, the dose-response analysis demonstrated a potentially non-linear relationship between FGF23 and stroke, HF, and all-cause mortality. In contrast, a potentially linear relationship between FGF23 and cardiovascular mortality was observed (p for non-linearity = 0.73). Conclusion: The present study suggests that increased serum FGF23 levels are positively related to CVD events and mortality in the general population. The clinical application of FGF23 levels to predict CVD risk requires further research.

Prevalence of NSAID use among people with COVID-19 and the association with COVID-19-related outcomes: Systematic review and meta-analysis.

AIM: Recent reports of potential harmful effects of nonsteroidal anti-inflammatory drugs (NSAIDs) in treating patients with coronavirus disease 2019 (COVID-19) have raised great concern. METHODS: We searched the PubMed, EMBASE, Cochrane Library and MedRxiv databases to examine the prevalence of NSAID use and associated COVID-19 risk, outcomes and safety. RESULTS: Twenty-five studies with a total of 101 215 COVID-19 patients were included. Prevalence of NSAID use among COVID-19 patients was 19% (95% confidence interval [CI] 14-23%, no. of studies [n] = 22) and NSAID use prior to admission or diagnosis of COVID-19 was not associated with an increased risk of COVID-19 (adjusted odds ratio [aOR] = 0.93, 95% CI 0.82-1.06, I2  = 34%, n = 3), hospitalization (aOR = 1.06, 95% CI 0.76-1.48, I2  = 81%, n = 5), mechanical ventilation (aOR = 0.71, 95% CI 0.47-1.06, I2  = 38%, n = 4) or length of hospital stay. Moreover, prior use of NSAIDs was associated with a decreased risk of severe COVID-19 (aOR = 0.79, 95% CI 0.71-0.89, I2  = 0%, n = 7) and death (aOR = 0.68, 95% CI 0.52-0.89, I2 = 85%, n = 10). Prior NSAID administration might also be associated with an increased risk of stroke (aOR = 2.32, 95% CI 1.04-5.2, I2  = 0%, n = 2), but not myocardial infarction (aOR = 1.49, 95% CI 0.25-8.92, I2  = 0, n = 2) and composite thrombotic events (aOR = 1.56, 95% CI 0.66-3.69, I2  = 52%, n = 2). CONCLUSION: Based on current evidence, NSAID use prior to admission or diagnosis of COVID-19 was not linked with increased odds or exacerbation of COVID-19. NSAIDs might provide a survival benefit, although they might potentially increase the risk of stroke. Controlled trials are still required to further assess the clinical benefit and safety (e.g., stroke and acute renal failure) of NSAIDs in treating patients with COVID-19.

Hyperuricemia Is Associated With the Risk of Atrial Fibrillation Independent of Sex: A Dose-Response Meta-Analysis.

Background: Conflicting findings of the association between serum uric acid (SUA) and atrial fibrillation (AF) have been reported in both men and women. The sex-specific associations between SUA and the risk of AF are unclear, although hyperuricemia is independently associated with the risk of AF. We performed this meta-analysis to assess the sex-specific effect of SUA on the risk of AF. Methods: The PubMed, EMBASE, and Cochrane Library databases were searched up to October 3, 2021, for studies that reported sex-specific associations of SUA levels with AF. Linear relationships were assessed by the generalized least squares trend estimation. This study was registered with PROSPERO (42020193013). Results: Ten eligible studies with 814,804 participants (415,779 men and 399,025 women) were identified. In the category analysis, high SUA was associated with an increased risk of AF in both men (OR: 1.42; 95% CI, 1.18-1.71, I2 = 34%) and women (OR: 2.02; 95% CI, 1.29-3.16, I2 = 70%). In the dose-response analysis, for each 60 µmol/L (1 mg/dL) increase in the SUA level, the risk of AF increased by 15% (OR: 1.15; 95% CI, 1.07-1.25, I2 = 74%) in men and 35% (OR: 1.35; 95% CI, 1.18-1.53, I2 = 73%) in women. There was a borderline difference in the impact of SUA on the risk of AF between men and women (P for interaction = 0.05). A significant linear relationship between SUA and the risk of AF was observed in men (P for non-linearity = 0.91) and women (P for non-linearity = 0.92). Conclusions: This study suggested that there was a significant linear relationship between SUA and the risk of AF among men and women, with a higher risk estimate for women. Additional trials are required to assess the effect of reduced SUA therapy on AF incidence. Systematic Review Registration: https:www.crd.york.ac.uk/PROSPERO/, identifier: CRD 42020193013.

Liver Fibrosis Scores and Hospitalization, Mechanical Ventilation, Severity, and Death in Patients with COVID-19: A Systematic Review and Dose-Response Meta-Analysis.

Methods: We identified relevant cohort studies that assessed the relationship between liver fibrosis scores (e.g., FIB-4, NAFLD fibrosis score (NFS), and aspartate aminotransferase to platelet ratio index (APRI)) and associated prognosis outcomes by searching the PubMed, EMBASE, and medRxiv databases. The potential dose-response effect was performed using a stage robust error meta-regression. Results: Sixteen studies with 8,736 hospitalized patients with COVID-19 were included. One-point score in FIB-4 increase was significantly associated with increased mechanical ventilation (RR: 2.23, 95% CI: 1.37-3.65, P=0.001), severe COVID-19 (RR: 1.82, 95% CI: 1.53-2.16, P < 0.001), and death (RR: 1.47, 95% CI: 1.31-1.65, P < 0.001), rather than hospitalization (RR: 1.35, 95% CI: 0.72-2.56, P=0.35). Furthermore, there is a significant positive linear relationship between FIB-4 and severe COVID-19 (P nonlinearity=0.12) and mortality (P nonlinearity=0.18). Regarding other liver scores, one unit elevation in APRI increased the risk of death by 178% (RR: 2.78, 95% CI: 1.10-6.99, P=0.03). Higher NFS (≥-1.5) and Forns index were associated with increased risk of severe COVID-19 and COVID-19-associated death. Conclusion: Our dose-response meta-analysis suggests high liver fibrosis scores are associated with worse prognosis in patients with COVID-19. For patients with COVID-19 at admission, especially for those with coexisting chronic liver diseases, assessment of liver fibrosis scores might be useful for identifying high risk of developing severe COVID-19 cases and worse outcomes.

Low vitamin D levels do not aggravate COVID-19 risk or death, and vitamin D supplementation does not improve outcomes in hospitalized patients with COVID-19: a meta-analysis and GRADE assessment of cohort studies and RCTs.

BACKGROUND: The associations between vitamin D and coronavirus disease 2019 (COVID-19) infection and clinical outcomes are controversial. The efficacy of vitamin D supplementation in COVID-19 is also not clear. METHODS: We identified relevant cohort studies that assessed the relationship between vitamin D, COVID-19 infection and associated death and randomized controlled trials (RCTs) that reported vitamin D supplementation on the outcomes in patients with COVID-19 by searching the PubMed, EMBASE, and medRxiv databases up to June 5th, 2021. Evidence quality levels and recommendations were assessed using the GRADE system. RESULTS: Eleven cohort studies with 536,105 patients and two RCTs were identified. Vitamin D deficiency (< 20 ng/ml) or insufficiency (< 30 ng/ml) was not associated with an significant increased risk of COVID-19 infection (OR for < 20 ng/ml: 1.61, 95% CI: 0.92-2.80, I2 = 92%) or in-hospital death (OR for < 20 ng/ml: 2.18, 95% CI: 0.91-5.26, I2 = 72%; OR for < 30 ng/ml: 3.07, 95% CI: 0.64-14.78, I2 = 66%). Each 10 ng/ml increase in serum vitamin D was not associated with a significant decreased risk of COVID-19 infection (OR: 0.92, 95% CI: 0.79-1.08, I2 = 98%) or death (OR: 0.65, 95% CI: 0.40-1.06, I2 = 79%). The overall quality of evidence (GRADE) for COVID-19 infection and associated death was very low. Vitamin D supplements did not significantly decrease death (OR: 0.57, I2 = 64%) or ICU admission (OR: 0.14, I2 = 90%) in patients with COVID-19. The level of evidence as qualified using GRADE was low. CONCLUSIONS: Current evidence suggested that vitamin D deficiency or insufficiency was not significantly linked to susceptibility to COVID-19 infection or its associated death. Vitamin D supplements did not significantly improve clinical outcomes in patients with COVID-19. The overall GRADE evidence quality was low, we suggest that vitamin D supplementation was not recommended for patients with COVID-19.

Dose-response relationship among body mass index, abdominal adiposity and atrial fibrillation in patients undergoing cardiac surgery: a meta-analysis of 35 cohorts.

BACKGROUND: Whether overweight increases the risk of postoperative atrial fibrillation (POAF) is unclear, and whether adiposity independently contributes to POAF has not been comprehensively studied. Thus, we conducted a meta-analysis to clarify the strength and shape of the exposure-effect relationship between adiposity and POAF. METHODS: The PubMed, Cochrane Library, and EMBASE databases were searched for revelant studies (randomized controlled trials (RCTs), cohort studies, and nest-case control studies) reporting data regarding the relationship between adiposity and the risk of POAF. RESULTS: Thirty-five publications involving 33,271 cases/141,442 patients were included. Analysis of categorical variables showed that obesity (RR: 1.39, 95% CI [1.21-1.61]; P < 0.001), but not being underweight (RR: 1.44, 95% CI [0.90-2.30]; P = 0.13) or being overweight (RR: 1.03, 95% CI [0.95-1.11]; P = 0.48) was associated with an increased risk of POAF. In the exposure-effect analysis (BMI) was 1.09 (95% CI [1.05-1.12]; P < 0.001) for the risk of POAF. There was a significant linear relationship between BMI and POAF (Pnonlinearity = 0.44); the curve was flat and began to rise steeply at a BMI of approximately 30. Notably, BMI levels below 30 (overweight) were not associated with a higher risk of POAF. Additionally, waist obesity or visceral adiposity index was associated with the risk of POAF. CONCLUSION: Based on the current evidence, our findings showed that high body mass index or abdominal adiposity was independently associated with an increased risk of POAF, while underweight or overweight might not significantly increase the POAF risk.

Green tea consumption and risk for esophageal cancer: A systematic review and dose-response meta-analysis.

OBJECTIVE: Controversial results of the association between green tea consumption and risk for esophageal cancer (EC) were reported by previous meta-analysis. Thus, the aim of this study was to quantitatively investigate the association. METHODS: The Cochrane Library, PubMed, and EMBASE databases were searched for relevant studies. We used a "one-stage approach" with a restricted cubic spline model to summarize the dose-specific relationships between green tea and risk for EC. Odds ratios (ORs) were used to measure the effects. Fourteen studies were included with a total of 5057 ECs among 493 332 participants. RESULTS: In the dose-response analysis, the summary OR for a 1 cup/d increase in green tea was 1.00 (95% confidence interval [CI], 0.95-1.04; I2 = 77%). No nonlinearity association was observed between tea consumption and risk for EC (P = 0.71 for nonlinearity). In the subgroup of sex, the summary OR for a 1 cup/d increase in green tea was 1.03 (95% CI, 0.95-1.11, I2 = 67%) for men and 0.79 (95% CI, 0.68-0.91; I2 = 0%) for women. CONCLUSION: Contrary to previous studies, based on current evidence, the present dose-response study suggested no association between green tea and risk for EC. However, there might be a protective effect of green tea in women. Notably, our conclusion might be influenced by limited studies and potential bias, such as dose of green tea assessment and select bias of case-control studies. Further larger number, prospective, and well-designed larger-scale studies are needed to provide more precise evidence, especially in women and more regions (United States and Europe).

The Prevalence and Associated Death of Ventricular Arrhythmia and Sudden Cardiac Death in Hospitalized Patients With COVID-19: A Systematic Review and Meta-Analysis.

BACKGROUND: Arrhythmia is a very common complication of coronavirus disease 2019 (COVID-19); however, the prevalence of ventricular arrhythmia and associated outcomes are not well-explored. Here, we conducted a systematic review and meta-analysis to determine the prevalence and associated death of ventricular arrhythmia and sudden cardiac death (SCD) in patients with COVID-19. METHODS: Databases of PubMed, Cochrane Library, Embase, and MdeRxiv were searched. Studies that could calculate the prevalence of ventricular arrhythmia/SCD during hospital admission or associated death in patients with COVID-19 were included. The study was registered with the PROSPERO (CRD42021271328). RESULTS: A total of 21 studies with 13,790 patients were included. The pooled prevalence of ventricular arrhythmia was 5% (95% CI: 4-6%), with a relatively high-SCD prevalence (1.8% in hospitalized COVID-19 and 10% in deceased cases of COVID-19). Subgroup analysis showed that ventricular arrhythmia was more common in patients with elevated cardiac troponin T [ES (effect size): 10%, 95% CI: -0.2 to 22%] and in European (ES: 20%, 95% CI: 11-29%) populations. Besides, ventricular arrhythmia was independently associated with an increased risk of death in patients with COVID-19 [odds ratio (OR) = 2.83; 95% CI: 1.78-4.51]. CONCLUSION: Ventricular arrhythmia and SCD resulted as a common occurrence with a high prevalence in patients with COVID-19 admitted to the hospital. Furthermore, ventricular arrhythmia significantly contributed to an increased risk of death in hospitalized patients with COVID-19. Clinicians might be vigilant of ventricular arrhythmias for patients with COVID-19, especially for severe cases. SYSTEMATIC REVIEW REGISTRATION: www.york.ac.uk/inst/crd, identifier: CRD42021271328.

Impact of body mass index on procedural complications, procedure duration, and radiation dose in patients with atrial fibrillation undergoing radiofrequency ablation: A systematic review and meta-analysis.

BACKGROUND: The association of body mass index (BMI) and procedure-related factors in patients with atrial fibrillation (AF) after radiofrequency ablation (RFA) is still unclear. HYPOTHESIS: BMI is associated with increased the radiation dose, procedure duration, and procedural complications. METHODS: Prospective studies assessing BMI and procedure duration, radiation dose, and procedural complications in patients with AF after RFA were identified through electronic searches of PubMed, Embase, and the Cochrane Library database. RESULTS: Ten studies with 14 735 participants undergoing RFA were included. Procedure duration was significantly longer in patients with overweight or obesity than in patients with normal BMI, with a mean difference (MD) of 0.95. Patients with overweight and obesity were exposed to a larger radiation dose, with standard MD of 1.71 and 1.98, respectively. There was no significant association between overweight or obesity and the risk of procedural complications (RR of 0.91 for overweight, 1.01 for obesity, 0.89 for stage I obesity, 1.00 for stage II obesity, and 0.94 for stage III obesity). Further analysis showed there was no significant difference regarding stroke or transient ischemic attack (overweight, RR: 0.92; obesity, RR: 1.02); cardiac tamponade (overweight, RR: 0.92; obesity, RR: 1.02); groin hematoma (overweight, RR: 0.62; obesity, RR: 0.40); or pulmonary vein stenosis (overweight, RR: 0.49; obesity, RR: 0.40) among BMI groups. CONCLUSION: Based on available evidence, we first showed that patients with overweight/obesity undergoing RFA experienced a significantly increased procedure duration and received a larger radiation dose than patients with normal BMI; however, there was no significant difference in procedural complications between patients with overweight/obesity and patients with normal BMI.

Dose-response analysis between hemoglobin A1c and risk of atrial fibrillation in patients with and without known diabetes.

BACKGROUND: The relationship between serum hemoglobin A1c (HbA1c) and atrial fibrillation (AF) or postoperative AF (POAF) in coronary artery bypass (CABG) patients is still under debate. It is also unclear whether there is a dose-response relationship between circulating HbA1c and the risk of AF or POAF. METHODS AND RESULTS: The Cochrane Library, PubMed, and EMBASE databases were searched. A robust-error meta-regression method was used to summarize the shape of the dose-response relationship. The RR and 95%CI were using a random-effects model. In total, 14 studies were included, totaling 17,914 AF cases among 352,325 participants. The summary RR per 1% increase in HbA1c was 1.16 (95% CI: 1.07-1.27). In the subgroup analysis, the summary RR was 1.13 (95% CI: 1.08-1.19) or 1.12 (95% CI: 1.05-1.20) for patients with diabetes or without known diabetes, respectively. The nonlinear analysis showed a nonlinear (Pnonlinear = 0.04) relationship between HbA1c and AF, with a significantly increased risk of AF if HbA1c was over 6.3%. However, HbA1c (per 1% increase) was not associated with POAF in patients with diabetes (RR: 1.13, P = 0.34) or without known diabetes (RR: 0.91, P = 0.37) among patients undergoing CABG. CONCLUSION: Our results suggest that higher HbA1c was associated with an increased risk of AF, both in diabetes and in without diabetes or with unknown diabetes. However, no association was found between HbA1c and POAF in patients undergoing CABG. Further prospective studies with larger population sizes are needed to explore the association between serum HbA1c level and the risk of POAF.