Continuation of Metformin Till Night Before Surgery and Lactate Levels in Patients Undergoing Coronary Artery Bypass Graft Surgery

Dapagliflozin for inpatient hyperglycemia in cardiac surgery patients with type 2 diabetes: randomised controlled trial (Dapa-Hospital trial)

AIMS

To examine the efficacy and safety of dapagliflozin in the treatment of hyperglycemia in cardiac surgery patients with type 2 diabetes (T2D).

METHODS

Cardiac surgery patients with T2D (n = 250) were randomly assigned (1:1) to receive dapagliflozin plus basal-bolus insulin (DAPA group) or basal-bolus insulin alone (INSULIN group) in the early postoperative period. The primary outcome was mean difference in daily blood glucose (BG) concentrations between groups. The major safety outcomes were the occurrence of severe ketonemia/diabetic ketoacidosis (DKA) and hypoglycemia. All analyses were performed according to the intention-to-treat principle.

RESULTS

The median age of the patients was 61 years (range, 55-61), and 219 (87.6%) were men. Overall, the randomization blood glucose was 165 mg/dL (SD, 37) and glycated hemoglobin was 7.7% (SD, 1.4). There were no differences in mean daily BG concentrations (149 vs. 150 mg/dL), mean percentage of readings within target BG of 70-180 mg/dL (82.7% vs. 82.5%), total daily insulin dose (mean, 39 vs. 40 units/day), number of daily insulin injections (median, 3.9 vs. 4), length of hospital stay (median, 10 vs. 10 days), or hospital complications (21.6% vs. 24.8%) between the DAPA and INSULIN groups. The mean plasma ketone levels were significantly higher in the DAPA group than in the INSULIN group at day 3 (0.71 vs. 0.30 mmol/L) and day 5 (0.42 vs. 0.19 mmol/L) of randomization. Six patients in the DAPA group developed severe ketonemia, but no patient developed DKA. There were no differences in the proportion of patients with BG < 70 mg/dL (9.6% vs. 7.2%) between the two groups.

CONCLUSION

Dapagliflozin complementary to basal-bolus insulin does not improve glycemia further over and above the basal-bolus insulin alone in hospitalized cardiac surgery patients. Dapagliflozin significantly increases plasma ketones levels. Safety of dapagliflozin in hospitalized patients needs further investigation. Trial registration ClinicalTrials.gov NCT05457933.

Efficacy and safety of degludec U100 versus glargine U300 for the early postoperative management of patients with type 2 diabetes mellitus undergoing coronary artery bypass graft surgery: A non-inferiority randomized trial

AIMS

To compare the efficacy and safety of degludec U100 versus glargine U300 for the early postoperative management of patients with type 2 diabetes mellitus (T2D) undergoing coronary artery bypass graft (CABG) surgery.

METHODS

A total of 239 patients were randomly assigned (1:1) to receive a basal-bolus regimen in the early postoperative period using degludec U100 (n = 122) or glargine U300 (n = 117) as basal and glulisine before meals. The primary outcome was mean differences between groups in their daily BG concentrations. The major safety outcome was the occurrence of hypoglycemia.

RESULTS

There were no differences in mean daily BG concentrations (157 vs. 162 mg/dl), mean percentage of readings within target BG of 70-180 mg/dl (74% vs. 73%), daily basal insulin dose (19 vs. 21 units/day), length of stay (median [IQR]: 9 vs. 9 days), or hospital complications (21.3% vs. 21.4%) between treatment groups. There were no differences in the proportion of patients with BG <70 mg/dl (15.6% vs. 23.1%) or <54 mg/dl (1.6% vs. 4.3%) between degludec-100 and glargine-300 groups.

CONCLUSIONS

Treatment with degludec U100 is as effective and safe as glargine U300 for the early postoperative hospital management of patients with T2D undergoing CABG.

A comparison of postoperative blood lactate concentrations and kinetics in cardiac surgical patients being and not being administered metformin

Aim. Early discontinuation of metformin before cardiac surgery is advised by several national societies but no hard evidence exist supporting this practice. This precaution is mostly extrapolated by data on different clinical settings. The aim of this study is to investigate the impact of preoperative metformin use on lactate concentrations and lactate clearance during the first postoperative day after cardiac surgery.Methods. Among 367 consecutive patients who underwent elective on-pump cardiac surgery from January 2019 to October 2019, 109 were diabetics, 74 of which were treated with metformin. Data on lactate concentrations and clearance during the first postoperative day were prospectively collected on arrival, H6, H12 and H24 in the ICU and compared. A subgroup analysis focusing only on diabetic patients was also performed. Repeated measures multivariate analysis of variance (MANOVA) was used to investigate the data based on group, time and their interaction effects.Results. Lactate concentrations were the same for both groups upon arrival in the ICU. Interestingly, metformin users had lower lactate concentrations than non-users on the following measurements (p = 0.003 at 6 h and p = 0.01 at 24 h). No significant interaction was found between the two groups (p = 0.76). No difference was found between the two groups in terms of lactate clearance (p = 0.53). In the subgroup analysis no difference was found between metformin users and non-users neither on lactate concentrations (p = 0.61) nor on lactate clearance (p = 0.86).Conclusions. In a post cardiac surgery ICU setting, using metformin up until the night before surgery was not associated with increased postoperative lactate concentrations or impaired lactate clearance.

Association of Metformin with the Mortality and Incidence of Cardiovascular Events in Patients with Pre-existing Cardiovascular Diseases

INTRODUCTION

Whether metformin reduces all-cause cardiovascular mortality and the incidence of cardiovascular events in patients with pre-existing cardiovascular diseases (CVD) remains inconclusive. Some randomised controlled trials (RCTs) and cohort studies have shown that metformin is associated with an increased risk of mortality and cardiovascular events.

METHODS

We conducted a pooling synthesis to assess the effects of metformin in all-cause cardiovascular mortality and incidence of cardiovascular events in patients with CVD. Studies published up to October 2021 in PubMed or Embase with a registration in PROSPERO (CRD42020189905) were collected. Both RCT and cohort studies were included. Hazard ratios (HR) with 95% CI were pooled across various trials using the random-effects model.

RESULTS

This study enrolled 35 published studies (in 14 publications) for qualitative synthesis and identified 33 studies (published in 26 publications) for quantitative analysis. We analysed a total of 61,704 patients, among them 58,271 patients were used to calculate all-cause mortality while 12,814 patients were used to calculate cardiovascular mortality. Compared with non-metformin control, metformin usage is associated with a reduction in all-cause mortality (HR: 0.90; 95% CI 0.83, 0.98; p = 0.01), cardiovascular mortality (HR: 0.89; 95% CI 0.85, 0.94; p < 0.0001), incidence of coronary revascularisation (HR: 0.79; 95% CI 0.64, 0.98; p = 0.03), and heart failure (HR: 0.90; 95% CI 0.87, 0.94; p < 0.0001) in patients with pre-existing cardiovascular diseases.

CONCLUSION

Metformin use is associated with a reduction in all-cause mortality, cardiovascular mortality, incidence of coronary revascularisation, and heart failure in patients with CVD; however, metformin usage was not associated with reduction in the incidence of myocardial infarction, angina, or stroke.

Increasing metformin concentrations and its excretion in both rat and porcine ex vivo normothermic kidney perfusion model

INTRODUCTION

Metformin can accumulate and cause lactic acidosis in patients with renal insufficiency. Metformin is known to inhibit mitochondria, while renal secretion of the drug by proximal tubules indirectly requires energy. We investigated whether addition of metformin before or during ex vivo isolated normothermic machine perfusion (NMP) of porcine and rat kidneys affects its elimination.

RESEARCH DESIGN AND METHODS

First, Lewis rats were pretreated with metformin or saline the day before nephrectomy. Subsequently, NMP of the kidney was performed for 90 min. Metformin was added to the perfusion fluid in one of three different concentrations (none, 30 mg/L or 300 mg/L). Second, metformin was added in increasing doses to the perfusion fluid during 4 hours of NMP of porcine kidneys. Metformin concentration was determined in the perfusion fluid and urine by liquid chromatography-tandem mass spectrometry.

RESULTS

Metformin clearance was approximately 4-5 times higher than creatinine clearance in both models, underscoring secretion of the drug. Metformin clearance at the end of NMP in rat kidneys perfused with 30 mg/L was lower than in metformin pretreated rats without the addition of metformin during perfusion (both p≤0.05), but kidneys perfused with 300 mg/L trended toward lower metformin clearance (p=0.06). Creatinine clearance was not different between treatment groups. During NMP of porcine kidneys, metformin clearance peaked at 90 min of NMP (18.2±13.7 mL/min/100 g). Thereafter, metformin clearance declined, while creatinine clearance remained stable. This observation can be explained by saturation of metformin transporters with a Michaelis-Menten constant (95% CI) of 23.0 (10.0 to 52.3) mg/L.

CONCLUSIONS

Metformin was secreted during NMP of both rat and porcine kidneys. Excretion of metformin decreased under increasing concentrations of metformin, which might be explained by saturation of metformin transporters rather than a self-inhibitory effect. It remains unknown whether a self-inhibitory effect contributes to metformin accumulation in humans with longer exposure times.