Are preoperative metformin prescriptions associated with a lower risk of postoperative mortality and readmission among patients with type 2 diabetes who underwent a major surgical intervention?

Reitz, K.M. et al. (2020). Association Between Preoperative Metformin Exposure and Postoperative Outcomes in Adults With Type 2 Diabetes. JAMA Surg. Published online April 08, 2020. doi:10.1001/jamasurg.2020.0416
Are preoperative metformin prescriptions associated with a lower risk of postoperative mortality and readmission among patients with type 2 diabetes who underwent a major surgical intervention? This is the question used to inform research into US patients with diabetes who were had a preoperative prescription and those without preoperative prescription, the research team looked at data from over 5000 patients who had undergone surgery. The researchers identified an association between metformin prescriptions before major surgery and reduced risk-adjusted mortality and readmission following the procedure (Source: Reitz, 2020 et al).

Key Points


Question
  Are preoperative metformin prescriptions associated with a lower risk of postoperative mortality and readmission among patients with type 2 diabetes who underwent a major surgical intervention?

Findings  In this cohort study of 5460 patients with diabetes who had a major surgical procedure, preoperative prescriptions of metformin were associated with a statistically significant decrease in the risk of 90-day mortality as well as 30- and 90-day readmission compared with no such prescriptions.

Meaning  Findings from this study suggest that preoperative metformin prescriptions may be associated with decreased postoperative mortality and readmission compared with no preoperative exposure to this medication, but further research is needed to ascertain if this relationship is causal.

Abstract

Importance  Adults with comorbidity have less physiological reserve and an increased rate of postoperative mortality and readmission after the stress of a major surgical intervention.

Objective  To assess postoperative mortality and readmission among individuals with diabetes with or without preoperative prescriptions for metformin.

Design, Setting, and Participants  This cohort study obtained data from the electronic health record of a multicenter, single health care system in Pennsylvania. Included were adults with diabetes who underwent a major operation with hospital admission from January 1, 2010, to January 1, 2016, at 15 community and academic hospitals within the system. Individuals without a clinical indication for metformin therapy were excluded. Follow-up continued until December 18, 2018.

Exposures  Preoperative metformin exposure was defined as 1 or more prescriptions for metformin in the 180 days before the surgical procedure.

Main Outcomes and Measures  All-cause postoperative mortality, hospital readmission within 90 days of discharge, and preoperative inflammation measured by the neutrophil to leukocyte ratio were compared between those with and without preoperative prescriptions for metformin. The corresponding absolute risk reduction (ARR) and adjusted hazard ratio (HR) with 95% CI were calculated in a propensity score–matched cohort.

Results  Among the 10 088 individuals with diabetes who underwent a major surgical intervention, 5962 (59%) had preoperative metformin prescriptions. A total of 5460 patients were propensity score–matched, among whom the mean (SD) age was 67.7 (12.2) years, and 2866 (53%) were women. In the propensity score–matched cohort, preoperative metformin prescriptions were associated with a reduced hazard for 90-day mortality; ARR, 1.28%  and hazard of readmission, with mortality as a competing risk at both 30 days and 90 days. Preoperative inflammation was reduced in those with metformin prescriptions compared with those without. E-value analysis suggested robustness to unmeasured confounding.

Conclusions and Relevance  This study found an association between metformin prescriptions provided to individuals with type 2 diabetes before a major surgical procedure and reduced risk-adjusted mortality and readmission after the operation. This association warrants further investigation.

 

Related: Diabetes UK Metformin associated with reduced mortality rates after major surgery

JAMA Surgery

Perioperative diabetes

Highs and lows: a review of the quality of care provided to patients over the age of 16 who had diabetes and underwent a surgical procedure

perioperative
Image source: http://www.hqip.org.uk

The aim of this study was to highlight where care could be improved in patients with diabetes undergoing surgery.  The overarching theme of the findings was that there was a lack of clinical continuity of diabetes management across the different specialties in the perioperative pathway.

The areas for improvements in care raised by this report, and the recommendations made, have the potential to impact a large portion of surgical patients, providing quality improvement goals for hospitals to measure their practice against.

Improving Diabetic Foot Care: A Guide for Commissioners

The College of Podiatry in collaboration with Health Education England and Insight Health Economics have produced a toolkit for commissioners in England to enable Diabetic Foot Care services to provided more effectively.

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The College are calling on healthcare commissioners to prioritise diabetic foot care and end avoidable amputations that can have a devastating impact on the lives of patients and their families and cost the NHS millions.

Complications from diabetic foot disease are costing the NHS in England more than a billion pounds a year. Today, and every day, 23 people with diabetes in England will have a toe, foot or leg amputated. A third of these are major amputations, meaning that the patient loses their whole foot above the ankle or even more of their leg. Many of these amputations are preceded by diabetes related foot ulcers, caused by a combination of impaired circulation and nerve damage – common problems experienced by people with diabetes.

Experts believe that by improving the way diabetic foot health is commissioned and delivered, around half of these life-shattering surgeries could be avoided.

Full detail: Improving Diabetic Foot Care: A Guide for Commissioners