Sustainable practice: Insulin therapy
BMJ 2024; 387 doi: https://doi.org/10.1136/bmj-2024-079425 (Published 25 October 2024) Cite this as: BMJ 2024;387:e079425Linked Editorial
Sustainable practice: what can I do?
- Tahseen A Chowdhury, consultant in diabetes1,
- Svetla Stefanova, senior diabetes nurse specialist1,
- Phillip Bennett-Richards, general practitioner2
- 1Department of Diabetes and Metabolism, The Royal London Hospital, London, UK
- 2The Aberfeldy Practice, London
- Correspondence to: TA Chowdhury Tahseen.chowdhury{at}nhs.net
What you need to know
Insulin prescribing is carbon intensive and leads to considerable plastic waste
Over the past decade, a broader range of medications has been made available to manage type 2 diabetes
If insulin prescribing is required, consider reusable pen devices
More than 500 million people live with diabetes, and around 783 million are expected to have the condition by 2045.1 Of this population, 5% to 15% have type 1 diabetes (T1D).2 Insulin therapy is necessary for people with T1D and for many living with type 2 diabetes (T2D) or other types of the condition (such as gestational diabetes). Waste from diabetes care includes disposables associated with insulin use, testing strips, lancets, needles, and continuous glucose monitoring (CGM) sensors. Many of these items are single use and wrapped in mixed plastics that are often difficult to recycle. Insulin therapy and glucose monitoring generate significant amounts of plastic waste, around 90% of which is packaging.3
Only around 9% of general plastic waste is recycled, and many plastics remain in the environment as microplastics, for which there is growing concern about potential harms.4 Insulin prescribing is only a small part of the 133 000 tonnes of plastic waste produced by the UK NHS each year,5 but healthcare professionals can mitigate the effect of insulin therapy on the environment while ensuring clinically appropriate diabetes management.
Why change is needed
England’s diabetes audit data from 2021 show that 21.8% of people with T1D, and 50.1% of people with T2D achieved a glycated haemoglobin of 53 mmol/mol (7.0%) or lower, suggesting that many people live with suboptimal glycaemic control.6 This is despite the fact that, during the same period, more than 7.7 million prescriptions for insulin were written in England, suggesting that despite insulin therapy, glycaemic control is frequently suboptimal.7 A life cycle analysis in the US and Sri Lanka suggests that one year of insulin use in a person with T2D results in production of 34.8 kg of carbon dioxide equivalent (CO2e); equivalent to driving 1250 km in a standard petrol car.8 In the UK, around 23 million medical pens (most of which are for insulin), are incinerated or sent to landfill each year.9
In people with T1D, use of continuous subcutaneous insulin infusion (CSII) and CGM sensors is likely to expand with the use of closed loop technology (semi-automated linked CGM and CSII). This is anticipated to become the preferred method of managing T1D because of its benefits for patients, including improved glucose control, reduced hypoglycaemia, and improved quality of life.10 CSII sets need changing every three days, and as a result generate considerable amounts of plastic waste, both in manufacture and packaging (fig 1). Recycling diabetes technology is complicated by the fact that many devices have electronic components such as glucose sensing built within a plastic coating. Many of these devices should be disposed of as per battery disposal.
Evidence for the solution
Methods to reduce the environmental impact of insulin therapy in people with diabetes should focus on optimising diabetes management and proper waste disposal, in which both patient and clinician can take a role.
Optimising diabetes care
Improving glycaemic control in people living with diabetes reduces the risk of micro and macrovascular complications and will in turn reduce the carbon footprint of healthcare interventions that these complications would require, such as dialysis.11 In some people with T2D, alternatives to insulin, such as very low calorie total dietary replacement to induce remission, may be feasible.12 Where clinically indicated, therapeutic alternatives to insulin, such as newer oral agents (for example, sodium glucose transporter-2 inhibitors; SGLT-2i) may generate less waste or carbon dioxide, although this has not yet been formally tested.
Proper waste disposal
The US-based Diabetes Technology Society “Green Diabetes Initiative” has published a strategy for minimisation, collection, separation, and disposal of diabetes device waste, emphasising the waste hierarchy five “Rs”: reducing, reusing, recycling, redesigning, and re-educating.13 They advocate the principles of a circular economy which addresses the preservation of resources through continuous recirculation.
What you can do
Optimise care, incorporating shared decision making
Review insulin use, doses, administration, timing, treatment concordance, storage.
Deprescribe, where clinically appropriate.
Stop medication that is ineffective or reduce medication if the person is overtreated. Avoid routinely recommending self-monitoring of blood glucose levels in people at low risk of hypoglycaemia.14
Suggest lifestyle interventions.
Discuss diet and physical activity recommendations. Consider whether the patient would benefit from structured education. Consider interventions to induce remission, eg, a very low calorie diet.11
In those with type 2 diabetes who are not already taking insulin and require further intervention to meet their agreed HbA1c target, consider alternatives where clinically appropriate
Ensure the patient’s non-pharmacological management has been optimised.
Review their current therapy, ensuring regular concordance and timing.
Consider whether the person is taking their treatment as prescribed. Are adverse effects such as gastrointestinal problems limiting concordance?
Consider additional treatments, such as SGLT2i to improve glucose control and reduce cardiovascular and renal risk when clinically appropriate.1415
If insulin is the best option for the patient, consider suggesting a reusable pen. Insulin is available in multiple dose disposable pen devices or in refillable pens. The latter produce considerably less plastic waste and carbon: 12 kg CO2e/year versus 7 kg,1617 although more time is required to educate the patient on using the device, and a degree of manual dexterity is needed to use the pens.
Reusable pen devices are available for most types of insulin, and can last up to three years. A recent analysis of data from the NHS suggested that around 72.5% of insulin prescribing was for disposable pens.18 This study suggested that replacing disposable insulin pens with reusable ones could reduce insulin pen-associated plastic waste by 84-95% and its carbon footprint by over 260 tonnes CO2e, as well as potential prescribing savings around £0.75 million per annum. Diabetes UK endorses the use of reusable pens to reduce plastic waste.19
If a disposable pen is the best option for the patient, consider a pen recycling scheme.
Several recycling schemes have been set up to manage plastic waste. Pencycle collects insulin (and GLP-1) pens for recycling (fig 2).9 A further scheme, which collects Tyvek films that cover trays carrying insulin pumps, sends these back to the manufacturer.20 The uptake and overall carbon impact of these schemes have yet to be evaluated, but manufacturers of Tyvek have data that suggest their recycling scheme reduced CO2e of 100 000 tonnes, equivalent to removing 22 000 cars from the road.21 Some companies have extended the requirement for changing infusion sets to seven days, resulting in significant reduction in plastic waste and reduction in costs of prescribing by $1324-$1677 per year.22
Ensure that prescribed insulin does not go to waste
Guide people with T1D (and perhaps people with T2D treated with bolus insulin) on how to dose insulin according to carbohydrate counting, so as not to over or underdose, leading to hypo or hyperglycaemia. Offer advice on how they can best manage their insulin supplies. Educate the person and their carers as to appropriate storage of insulin to prevent denaturation. For example, insulin not currently in use should be stored in the refrigerator, and the use of personal cool bags when travelling is recommended to ensure the insulin does not freeze or overheat. This is not only a sustainability consideration but also a patient safety issue as insulin that has been stored incorrectly may not have the expected effect on blood glucose.
Patient perspective
I have had type 1 diabetes for almost 20 years. I get through around two pens per week, so guess I have disposed of more than 2000 pens in my lifetime. I am very concerned about the effect on the environment, especially for my children. My consultant spoke to me about using a reusable pen, but I have some problems with arthritis, so I found it difficult to use. I now send all of my empty pens to the “Pencycle” scheme, and will continue to do so. I am concerned that my glucose sensor device is just put in the bin at the end of two weeks’ use. I wish the company would find a way to reuse them.
Education into practice
How many of your patients use reusable pen devices?
What educational activities could you consider within your practice to encourage the use of reusable pens and pen recycling schemes?
How patients were involved in the creation of this article
We spoke to a person with T1D about their concerns regarding plastic waste, and included their response in the article (Patient perspective). Many of our patients have responded positively to encouragement to use pen recycling schemes or to convert to using reusable pens.
We also consulted PBR, a person living with T2D who has enthusiastically started recycling his disposable pens, and supplied the image in fig 2.
Footnotes
This article is part of a series that offers practical actions clinicians can take to support reaching net zero. Browse all the articles at https://sandpit.bmj.com/graphics/2023/tangibleActions-v8/. To pitch your idea for an article go to https://bit.ly/46Etl9i
Contributorship and the guarantor: TAC conceived the article and is guarantor. All authors wrote and reviewed the article.
Competing interests: The BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the following other interests: none.
Provenance and peer review: commissioned; externally peer reviewed.