Diathermy On Diabetes Glucose Monitoring Effectiveness (DODGE)

Assessing the Impact of Intraoperative Diathermy on Accuracy and Functioning of Glucose Monitoring Systems

The goal of this observational study is to investigate if diathermy (a surgical tool that uses electrical energy to control bleeding) has any affect on the accuracy and functioning of continuous glucose monitoring systems in adults and young people with Type 1 Diabetes. The main questions this study aims to answer is -

- Does the accuracy of continuous glucose monitoring systems change after use of diathermy?

Participants will:

• Have their height and weight checked.
• Provide information about their medical history including type of diabetes, other medical conditions and any current medications they take.
• Have paired glucose meter and sensor glucose measurements taken every 15-75 minutes from up to 4 hours before surgery until up to 4 hours after the end of surgery.
• Have two blood samples taken to measure glucose levels, The first one will be before the use of diathermy and the second will be after the use of diathermy.

Study Overview

• Status: Not yet recruiting
• Conditions: Type 1 Diabetes Mellitis

Detailed Description

Background and rationale:

The incidence of type 1 diabetes is rising and technology is an increasingly important part of monitoring and responding to glucose levels. Contemporary monitoring of glucose levels using continuous glucose monitoring (CGM) systems provide users with information about their glucose levels in real time without finger-prick capillary glucose testing. Crucially, these new systems provide information about the trend in blood glucose levels and is now standard in type 1 diabetes. Use of CGM systems is also needed for patients who use "closed loop" systems which adjust insulin at, typically, 5-minute intervals in response to glucose levels. Use of these strategies in glucose level monitoring and management improves long-term outcomes for persons living with diabetes and is now standard of care in type 1 diabetes. Their importance during inpatient admissions and surgery is increasingly recognised but data is limited.

During surgery, diathermy is often used to control bleeding by using high-frequency electrical energy to seal small blood vessels. Available literature supports the hypothesis that CGM systems may not be affected by diathermy, but there is limited information on the actual impact of diathermy on the accuracy of CGM systems. At present, CGM systems warranties are invalidated by diathermy use. Consequently, patients undergoing surgery require a period of blood glucose testing to monitor and respond to glucose levels which are often rendered unstable in the period around surgery. This exposes patients to potentially unnecessary interventions and, for those patients who are needle-phobic or have learning difficulties, the need to renew repeated finger-prick capillary blood testing around surgery may be a significant barrier to effective and optimal glucose monitoring and control. In addition, there may be a delay in responding to hypoglycaemia and hyperglycaemia, due to the time between measurements.

This study aims to assess the impact of intraoperative diathermy use on the accuracy and functioning of CGM systems. Demonstrating that glucose monitoring systems could be effectively used during surgery would:

• Prevent/reduce the need for the anaesthetic team to access the patients' fingers/toes and venous/arterial lines for blood glucose testing during surgery.
• Provide easy, convenient and accurate glucose monitoring to the anaesthetic team, with data transmitted from monitoring systems which can remain underneath surgical coverings.
• Provide prompt, real-time information on glucose trends during surgery, leading to better control of glucose levels including earlier recognition of low and high glucose levels (hypoglycaemia and hyperglycaemia, respectively).

Study design:

This is a single-centre, prospective, single-arm, observational, non-inferiority study of adults and young people with diabetes using CGM systems. 126 participants will be recruited. Sample size was calculated using simulation.

Participants will undergo paired glucometer and sensor glucose measurements every 15-75 minutes from up to 4 hours before the planned time of surgery until up to 4 hours after the completion of surgery, for not more than 24 hours. They will also have two venous blood samples taken for glucose concentration analysis.

Patient recruitment:

Participants will be recruited from patients due to have an elective surgical procedure at Nottingham University Hospital NHS Trust. The initial approach may be from a member of the patient's usual care team with consent to share contact details with the study team. In addition, the Trust's Theatre Management system (Nervecentre) will be reviewed to identify patients with type 1 diabetes who are due to attend for surgery.

Data management and analysis:

Data will be collected by members of the research team using study specific case report forms (CRFs). An ANOVA mixed effects model will be used with participant as a random effect and pre/post diathermy as a fixed effect. An equivalence F-test with an ARD equivalence value of 0.05 will be performed to determine effect of diathermy on ARD.

Quality assurance plan:

Monitoring of study data shall include confirmation of informed consent; source data verification; data storage and data transfer procedures; local quality control checks and procedures, back-up and disaster recovery of any local databases and validation of data manipulation. Entries on CRFs will be verified by inspection against the source data. A 10% sample of CRFs will be checked on a regular basis for verification of all entries made. In addition, the subsequent capture of the data on the study database will be checked. Where corrections are required, these will carry a full audit trail and justification. Study data and evidence of monitoring and systems audits will be made available for inspection by the REC as required.

Reporting adverse effects:

Intraoperative glucose monitoring is currently undertaken using blood glucose meters. The same monitoring will be continued through this study and this study involves no deviation from standard care. Sensor glucose measurements are passively recorded from the participant's receiving device and eligible participants would already be routinely using sensors as part of their diabetes care.

Equipment failure issues, where a sensor or blood glucose measurement is not able to be obtained, will be recorded on the CRF. Adverse events as a result of participation within this study are not expected but will be recorded on an Adverse Event Form if any occurs. Clinical deterioration and surgical complications, not related to the study, will be considered expected in terms of classification.

• Study Type: Observational
• Enrollment (Estimated): 126

Contacts and Locations

Study Locations

• United Kingdom
  • Nottingham, United Kingdom
    • Queen's Medical Centre
    • Contact: James Armstrong, BMBS; Phone Number: 0115 924 9924; Email: james.armstrong8@nhs.net
    • Contact: James M Law, PhD, BMBS; Email: james.law@nottingham.ac.uk
    • Principal Investigator: James Armstrong, BMBS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients aged 4 or older with type 1 diabetes mellitus scheduled to undergo elective surgery at Nottingham Universities Hospitals NHS Trust.

Description

Inclusion Criteria:

• Diagnosis of type 1 diabetes mellitus.
• Planned admission for elective surgery at Nottingham University Hospitals NHS Trust.
• Currently routinely using a prescribed Abbott Libre-2, Abbott Libre-3, Dexcom G6 or Dexcom G7 glucose monitoring system to monitor glucose concentrations.
• Aged 4 years or older on the day of surgery.
• Ability to give informed consent / ability of parent/carer to give informed consent (as appropriate).

Exclusion Criteria:

• Use of paracetamol above maximum dose within 7 days before the scheduled date of surgery (in adults with body weight under 51kg - maximum of 60mg/kg per day, in adults with body weight 51kg and above - maximum of 4g per day, in children - maximum dose as per their age as stated in the British National Formulary for Children)
• Any use of hydroxyurea within 7 days before the scheduled date of surgery
• Use of more than 500mg per day of ascorbic acid / vitamin C within 7 days before the scheduled date of surgery
• Currently taking medications as part of a clinical trial.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Patients with T1DM aged 4 or older routinely using CGM systems undergoing elective surgery; Patients (aged 4 or above) with a diagnosis of type 1 diabetes mellitus who routinely use a prescribed Abbott Libre-2, Abbott Libre-3, Dexcom G6 or Dexcom G7 glucose monitoring system to monitor glucose concentrations. Patients will scheduled to have a planned admission for elective surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To assess if the Absolute Relative Differences (ARDs) of continuous glucose monitoring systems change after use of diathermy.	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (glucometer) glucose reading (mmol/L) divided by the reference reading. The null hypothesis is that there is no difference (non-inferiority) following diathermy (where equivalence is defined as less than a 0.05 difference in ARD).	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To assess whether ARD changes following diathermy depending on type of diathermy used (bipolar/monopolar).	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (glucometer) glucose reading (mmol/L) divided by the reference reading. Equivalence is defined as less than a 0.05 difference in ARD.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.
To assess whether ARD changes following diathermy when the model is adjusted for glucose trend (rate of change).	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (glucometer) glucose reading (mmol/L) divided by the reference reading. Equivalence is defined as less than a 0.05 difference in ARD.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.
To assess whether ARD changes following diathermy when the model is adjusted for duration of surgery (minutes).	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (glucometer) glucose reading (mmol/L) divided by the reference reading. Equivalence is defined as less than a 0.05 difference in ARD.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.
To assess whether ARD changes following diathermy when the model is adjusted for site of surgery.	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (glucometer) glucose reading (mmol/L) divided by the reference reading. Equivalence is defined as less than a 0.05 difference in ARD.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.
To assess whether ARD changes following diathermy according to participant characteristic of age (years).	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (glucometer) glucose reading (mmol/L) divided by the reference reading. Equivalence is defined as less than a 0.05 difference in ARD.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.
To assess whether ARD changes following diathermy according to participant characteristic of weight (kg).	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (glucometer) glucose reading (mmol/L) divided by the reference reading. Equivalence is defined as less than a 0.05 difference in ARD.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.
To assess whether ARD changes following diathermy according to participant characteristic of BMI (or BMI SDS in under 18s).	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (glucometer) glucose reading (mmol/L) divided by the reference reading. Equivalence is defined as less than a 0.05 difference in ARD.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.
To assess sensor accuracy before and after diathermy using error grid analysis.	Error grid analysis will be used to assess the effect of CGM systems accuracy after diathermy use on clinical decision making.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.
To assess whether the ARD of each system changes after use of diathermy using laboratory glucose concentration results as the reference readings.	The ARD is the absolute difference between the sensor reading (mmol/L) and the reference (laboratory glucose concentration) glucose reading (mmol/L) divided by the reference reading. Equivalence is defined as less than a 0.05 difference in ARD.	From up to 4 hours prior to the start of surgery to 4 hours after the end of surgery, for no more than a total of 24 hours.

Collaborators and Investigators

• Sponsor: University of Nottingham
• Investigators: Study Director: James M Law, PhD, BMBS, University Hospitals of Derby and Burton NHS Foundation Trust, University of Nottingham; Principal Investigator: James Armstrong, BMBS, Nottingham University Hospitals NHS Trust

Publications and helpful links

General Publications

• Avari P, Lumb A, Flanagan D, Rayman G, Misra S, Dhatariya K, Choudhary P. Continuous Glucose Monitoring Within Hospital: A Scoping Review and Summary of Guidelines From the Joint British Diabetes Societies for Inpatient Care. J Diabetes Sci Technol. 2023 May;17(3):611-624. doi: 10.1177/19322968221137338. Epub 2022 Nov 28.
• Gregory GA, Robinson TIG, Linklater SE, Wang F, Colagiuri S, de Beaufort C, Donaghue KC; International Diabetes Federation Diabetes Atlas Type 1 Diabetes in Adults Special Interest Group; Magliano DJ, Maniam J, Orchard TJ, Rai P, Ogle GD. Global incidence, prevalence, and mortality of type 1 diabetes in 2021 with projection to 2040: a modelling study. Lancet Diabetes Endocrinol. 2022 Oct;10(10):741-760. doi: 10.1016/S2213-8587(22)00218-2. Epub 2022 Sep 13.
• Using technology to support diabetes care in hospital (2024). Joint British Diabetes Societies for Inpatient Care (JBDS-IP) Group and Diabetes Technology Network (DTN). Available at: https://abcd.care/sites/default/files/resources/JBDS_20_Using_Technology_to_Support_Diabetes_Care_in_Hospital_1.pdf (Accessed: 16 May 2024).
• Type 1 diabetes in adults: QS208 (2023). National Institute for Health and Care Excellence. Available at: https://www.nice.org.uk/guidance/qs208.
• Parkes JL, Slatin SL, Pardo S, Ginsberg BH. A new consensus error grid to evaluate the clinical significance of inaccuracies in the measurement of blood glucose. Diabetes Care. 2000 Aug;23(8):1143-8. doi: 10.2337/diacare.23.8.1143.
• Kovatchev BP, Gonder-Frederick LA, Cox DJ, Clarke WL. Evaluating the accuracy of continuous glucose-monitoring sensors: continuous glucose-error grid analysis illustrated by TheraSense Freestyle Navigator data. Diabetes Care. 2004 Aug;27(8):1922-8. doi: 10.2337/diacare.27.8.1922.
• Hybrid closed loop systems for managing blood glucose levels in type 1 diabetes. London: National Institute for Health and Care Excellence (NICE); 2023 Dec 19. No abstract available. Available from http://www.ncbi.nlm.nih.gov/books/NBK613531/
• Campbell H, Lakens D. Can we disregard the whole model? Omnibus non-inferiority testing for R2 in multi-variable linear regression and etâ2 in ANOVA. Br J Math Stat Psychol. 2021 Feb;74(1):64-89. doi: 10.1111/bmsp.12201. Epub 2020 Feb 13.
• Krutkyte G, Rolfes ED, Herzig D, Guensch DP, Schweizer T, Wuethrich PY, Beldi G, Vogt AP, Bally L. Performance of the DEXCOM G7 CGM system during and after major surgery. Diabetes Obes Metab. 2025 Aug;27(8):4586-4589. doi: 10.1111/dom.16462. Epub 2025 May 21. No abstract available.

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): February 1, 2027

Study Registration Dates

• First Submitted: April 13, 2026
• First Submitted That Met QC Criteria: May 6, 2026
• First Posted (Actual): May 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 6, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Type 1 Diabetes Mellitus; Diathermy; post-operative; pre-operative; intraoperative; Continuous Glucose Monitoring Systems; Peri-operative care; Capillary blood glucose; Sensor blood glucose; Intra-operative T1DM management
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Autoimmune Diseases; Immune System Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Body Temperature Changes; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Diabetes Mellitus, Type 1; Fever
• Other Study ID Numbers: 25018

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No