Is it necessary to discontinue metformin in diabetic patients with GFR > 60 ml/min per 1.73 m2 undergoing coronary angiography: A controversy still exists?

Metformin Can Be Safely Used in Patients Exposed to Contrast Media: A Systematic Review and Meta-Analysis

BACKGROUND

There have been few studies published on the use of contrast media (CM) in metformin-treated patients. In this study, we conducted a systematic review and meta-analysis to investigate the relationship between metformin and contrast-induced acute kidney injury (CI-AKI).

METHODS

A comprehensive search of the Medline, PubMed, Embase, and Web of Science databases for literature on associations between metformin use and CI-AKI incidence was conducted. The pooled odds ratio (OR), or relative risk, as well as the corresponding 95% confidence intervals (CIs), was calculated to assess the relationship between metformin and CI-AKI risk as well as the incidence of lactic acidosis (LA).

RESULTS

In total, seven studies met our eligibility criteria on associations between metformin use and CI-AKI incidence, comprising 2,325 individuals, with 279 new cases of CI-AKI exposed to CM. The pooled analysis revealed no statistically significant increase in the risk of CI-AKI development in patients who used metformin continuously (random-effects OR: 1.15, 95% CI: 0.70-1.90, p = 0.57). No cases of LA that occurred during CM exposure were reported.

CONCLUSION

Metformin can be safely used in patients with moderate renal impairment (eGFR ≥ 30 mL/min/1.73 m2) during CM exposure.

Continuous use of metformin in patients receiving contrast medium: what is the evidence? A systematic review and meta-analysis

OBJECTIVES

Substantial inconsistencies exist in current guidelines regarding recommendations of metformin usage with the administration of a contrast medium. We aimed to perform a meta-analysis to determine whether the risks of contrast-induced acute kidney injury (CI-AKI) and lactic acidosis increase with metformin use in diabetic patients receiving a contrast medium.

METHODS

Studies were retrieved from databases from inception to May 15, 2021. Studies that compared the outcomes of using metformin with not using metformin during contrast medium administration were included. The primary outcomes were incidence of CI-AKI and lactic acidosis. The secondary outcomes were renal function changes from baseline. Data analysis was using risk ratio (RR) for dichotomous outcomes and mean differences (MD) with 95% confidence intervals (CI) for continuous outcomes.

RESULTS

Analyses of two randomized controlled trials and four retrospective cohorts examining a total of 1459 patients revealed no significant differences in the incidence of CI-AKI (RR = 1.08; 95% CI, 0.72 to 1.63) and in changes in renal function measurements (serum creatinine: MD = 0.00 mg/dL, 95% CI, - 0.05 to 0.05; estimated glomerular filtration rate: MD = 0.22, 95% CI, - 2.47 to 2.91) after contrast medium administration between patients using and not using metformin.

CONCLUSIONS

There is no evidence that continuing metformin during contrast medium administration is associated with a higher risk of CI-AKI, lactic acidosis, or renal function deterioration compared to patients who discontinued metformin or who were not metformin users. The limited quality of the included studies may compromise the strength of evidence provided in this meta-analysis.

KEY POINTS

There is no need to discontinue metformin either before or after intravenous contrast medium exposure in patients with eGFR > 30 mL/min/1.73 m2. In patients receiving intra-arterial contrast medium with first-pass renal exposure, there is no need to withhold metformin if eGFR is above 60 mL/min/1.73 m2. For patients who have an eGFR level between 30 and 60 mL/min/1.73 m2 and are receiving intra-arterial contrast medium with first-pass renal exposure, no case of lactic acidosis was observed based on present data, but further evidence is needed to make a strong suggestion regarding its safety.

Glycemic Control in Hospitalized Stroke Patients: A Review

PURPOSE OF REVIEW

The purpose of this review is to discuss clinical trials involving glycemic control in hospitalized stroke patients and to review oral medications used in glycemic control. GLP-1 agonists, which have some preliminary studies in ischemic stroke, will also be reviewed.

RECENT FINDINGS

Until recently, glycemic control targets in hospitalized stroke patients remained unclear. The SHINE (Stroke Hyperglycemia Insulin Network Effort) trial demonstrated no significant difference between aggressive versus standard of care glycemic control in the acute ischemic stroke patient. Although SHINE demonstrated a lack of statistical difference in glycemic control targets, many questions remain including glycemic control in patients with other stroke types (SAH, ICH). The role of non-insulin-based medications in glycemic control for hospitalized stroke patients remains unclear and presents an opportunity for further research. Finally, GLP-1 agonists present an interesting area of research for acute ischemic stroke.

Effect of continuous use of metformin on kidney function in diabetes patients with acute myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

Diabetes patients presenting with ST-segment elevation myocardial infarction (STEMI) scheduled for primary percutaneous coronary intervention (PCI) have an increased risk of contrast induced-acute kidney injury (CI-AKI). The effects of continuous use of metformin on kidney function are still controversial in patients submitted to primary PCI. This study aimed to assess continuous metformin therapy on kidney function in diabetic patients undergoing coronary intervention.

METHODS

Two hundred eighty-four patients with metformin-treated diabetes, who underwent coronary intervention within 24 h for STEMI, were enrolled in the retrospective study. All the patients had estimated glomerular filtration rate (eGFR) of > 30 mL/min/1.73 m2. According to the physicians' decisions after admission, 119 patients continued metformin treatment after primary PCI, while 165 patients discontinued it > 48 h after the procedure. Serum creatinine was collected at admission and within 48 h post primary PCI to evaluate the incidence of CI-AKI. We performed a multiple logistic regression analysis to examine the determinants of CI-AKI.

RESULTS

No statistical difference in CI-AKI incidence between the continuous and the discontinuous metformin group (12.6%vs10.3%, p = 0.545). Multivariable logistic regression analysis indicated eGFR ≤60 ml/min/1.73 m2[p = 0.025, OR: 3.131; 95% CI (1.156-8.482)] and contrast volume [p = 0.002, OR: 1.010; 95% CI (1.004-1.016)] were predictive factors of CI-AKI. Metformin therapy was irrelevant to CI-AKI [p = 0.365, OR: 0.698; 95% CI (0.320-1.521)]. No case of lactic acidosis was found in this study. Besides, the study supported discontinuation of metformin was not beneficial for patients' blood glucose control after admission.

CONCLUSIONS

The study indicated that the metformin continuation after primary PCI for STEMI in diabetic patients with eGFR > 30 ml/min / 1.73 m2 did not increase the risk of CI-AKI.

Metformin, arterial contrast and acute kidney Injury

BACKGROUND AND AIM OF THE WORK

We aim to respond to interesting article in your journal by Namazi et al. regarding metformin use in patients undergoing coronary angiography and risk of developing metformin associated lactic acidosis. We share our experience regarding patients using metformin undergoing urgent coronary angiography and risk of developing contrast induced nephropathy.

METHODS

A retrospective chart review of 154 patients who underwent emergency coronary angiography (CAG) with arterial contrast exposure. The study was approved by the institution review board (Metrowest Medical Center IRB, Framingham Massachusetts, USA).

RESULTS

154 patients admitted with acute coronary syndrome during months of January 2014 - December 2014; 67 patients used metformin (100% had diabetes mellitus) whereas 87 were not on metformin (31% had diabetes mellitus). Our study revealed no difference in contrast induced nephropathy (CIN) between the two groups (p=0.29), when compared at 48 hours after arterial contrast exposure. Higher serum creatinine may be have precluded the use of metformin in the control group.

CONCLUSIONS

Our single center, small observational study showed no difference in the incidence of CIN in patients who continued to be on metformin after arterial contrast exposure compared to the control group.