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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Continuous subcutaneous insulin infusions, or pumps, reduced the amount of daily insulin required by 24 units for people with advanced type 2 diabetes compared to multiple daily insulin injections. Average weight did not differ between treatments.
This review compared the two treatments in 590 people from five trials and found that the pumps were linked to slightly better control for people on higher doses of insulin and those with poorer glucose control. However, looking at all the people with diabetes in these studies, there was no difference in overall control between the different forms of treatment.
One main challenge in controlling type 2 diabetes is the low adherence to treatment. Other studies have found that this may be improved with continuous insulin pumps. Larger studies will be required to confirm if this is the case and to assess the safety of the technique for advanced type 2 diabetes as it is currently only recommended for type 1 diabetes.
This treatment option is more expensive than multiple daily injections so cost-effectiveness will also need to be looked at. Nevertheless, these are promising results for people with poorly controlled type 2 diabetes.
Why was this study needed?
In 2015 around 3.8 million people were estimated to live with diabetes in England, and nine out of ten of them had type 2 diabetes. The NHS spends £8.8 billion per year on type 2 diabetes alone.
A healthy diet and exercising are the mainstay of management to help control sugar levels and prevent complications of diabetes. The disease requires also close monitoring of sugar levels to avoid serious complications. Insulin injections are among treatment options for advanced stages of the disease, but approximately one in every four people on insulin injections has a very poor control of blood sugar levels. Evidence on insulin pumps in type 2 diabetes is sparse compared to the evidence in type 1 diabetes.
This study aimed to assess blood sugar control using continuous subcutaneous insulin infusions in type 2 diabetes in order to inform the development of patient-centred treatment approaches.
What did this study do?
This meta-analysis included five randomised controlled trials comparing continuous insulin pumps with multiple injections for blood sugar control in 590 people with type 2 diabetes. Study duration varied between three and 24 months.
The main outcome was glycated haemoglobin level, which provides an indication of the average blood sugar levels in the previous two to three months. Secondary outcomes were insulin dose and weight change. Disease control was compared between initiation, or baseline, and completion of the study.
The main limitations are the different multiple injection treatment options, different population size across studies and variability between patients’ characteristics, including baseline glycated haemoglobin and insulin dose. In addition, participants and health professionals were aware of the treatment type.
What did it find?
- There was no statistically significant difference in final glycated haemoglobin levels between people using insulin pumps compared with multiple injections (effect size [ES] -0.40%, 95% confidence interval [CI] -0.86 to 0.05). The average HbA1c baseline level was 8.8% (73 mmol/mol), indicating poor control. There was also a large degree of heterogeneity across trials (I2 81.1%) explained by the variation of baseline variation in HbA1c from 8.1% (65 mmol/mol) in some trials to 9.6% (81 mmol/mol) in those with the poorest initial control.
- Treatment with continuous pumps reduced the daily insulin dose by 24 units compared with multiple injections (95% CI -30.6 units to -17.5 units).
- There was no difference in body weight between the two treatments (ES 0.08 kg, 95% CI -0.33 to 0.48).
- The higher the baseline glycated haemoglobin level or dose of insulin, the more effective the continuous insulin pumps were compared to multiple injections.
What does current guidance say on this issue?
The NICE guideline on continuous insulin pumps for the treatment of diabetes recommends against its use in people with type 2 diabetes due to a lack of supporting evidence. The guideline was published in 2008 and reviewed in 2011. It is planned to be reviewed if new evidence is likely to affect the recommendations. The NICE 2015 guideline on management of type 2 diabetes does not include continuous insulin pumps as an option.
The SIGN guideline on management of diabetes, published in 2010 and updated in 2013, only recommends the use of continuous insulin pumps for type 1 diabetes.
What are the implications?
The findings of this study suggest that continuous insulin pumps may be more effective in controlling type 2 diabetes than multiple daily injections, especially in people with poorly controlled disease and on high insulin doses.
Continuous pumps are used in type 1 diabetes, so additional training of the workforce in order to use them in type 2 patients is not anticipated.
Though this review shows promising results, larger randomised controlled trials and cost-effectiveness studies will be required to validate the findings. They will also need to look at safety aspects that were not included in these studies, such as the incidence of hypoglycaemia (low blood sugar).
Citation and Funding
Pickup JC, Reznik Y, Sutton AJ. Glycemic control during continuous subcutaneous insulin infusion versus multiple daily insulin injections in type 2 diabetes: individual patient data meta-analysis and meta-regression of randomized controlled trials. Diabetes Care. 2017;40(5):715-22.
No funding information was provided for this study.
Bibliography
NHS Choices. Type 2 diabetes. London: Department of Health; 2016.
NICE. Type 2 diabetes in adults: management. NG28. London; 2015.
NICE. Continuous subcutaneous insulin infusion for the treatment of diabetes mellitus. TA151. London: National Institute for Health and Clinical Excellence; 2008.
PHE. 3.8 million people in England now have diabetes. London: Public Health England; 2016.
SIGN. Management of diabetes. No. 116. Edinburgh: Scottish Intercollegiate Guidelines Network; 2010.
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