This systematic review found that a range of educational and technological interventions could help adults with type 1 diabetes regain awareness of when they have low blood glucose (hypoglycaemia). Nearly one in every three adults with type 1 diabetes stops noticing low blood sugar levels. This means they cannot take action quickly to prevent a medical crisis. People with low awareness of their blood sugar levels are six times more likely to have severe hypoglycaemia, which can cause fits and even coma.
The authors recommended an approach to restoring awareness that starts with structured teaching about flexible insulin therapy and adjusting insulin doses. If the person still had impaired awareness, the review suggests they should be offered technological options such as continuous blood glucose monitors or insulin pumps alongside more frequent contact with health services. These findings support a practical stepped approach to management and the recent 2015 NICE guideline recommendations.
Why was this study needed?
By 2013, around 280,000 people in the UK had been diagnosed with type 1 diabetes, which requires frequent injections of insulin to keep blood glucose within normal levels. Not achieving normal levels can lead to long-term complications such as damage to nerves, eyesight and kidneys. However, because the body’s insulin needs vary, there is a risk of taking too much insulin. The surplus insulin reduces blood glucose to below normal levels, called hypoglycaemia, which can cause problems such as dizziness or, in severe cases, seizures or coma.
Recurring episodes of hypoglycaemia can reduce the body’s hormone responses to low sugar and lead to impaired awareness. This increases the risk of the fall in sugar becoming severe, a life threatening medical emergency. This was the first systematic review to assess interventions for restoring awareness of hypoglycaemia for adults with type 1 diabetes.
What did this study do?
This systematic review included 43 studies, 18 randomised controlled trials and 25 before-and-after studies, which looked at educational, technological or pharmacological ways to improve awareness of hypoglycaemia. Educational interventions were either based on established programmes to routinely teach patients to manage their own insulin, such as Dose Adjustment for Normal Eating (DAFNE), or other more intensive psychoeducation programmes specifically aimed at restoring awareness. Technological interventions included continuous subcutaneous insulin pump infusion, and continuous glucose monitoring. Trials of pharmacological interventions mostly compared different forms of insulin or those with different lengths of action. All participants in these underlying trials had type 1 diabetes; some also had impaired awareness of hypoglycaemia. Outcomes included severe hypoglycaemic events requiring assistance, or restoration of hypoglycaemia awareness as measured by standard scales.
The review process was rigorously designed. However, most of the studies were observational, and only six studies’ results could be combined in a meta-analysis, reducing the reliability of the results.
What did it find?
- In the before and after studies, standard educational interventions, based on adult learning principles, reduced episodes of severe hypoglycaemia from about eight per year to six per year. They also improved blood glucose control and awareness of hypoglycaemia.
- There were slightly greater benefits in improving awareness of hypoglycaemia, in those lacking awareness, when educational programmes included psychotherapeutic and behavioural techniques.
- Technological approaches reduced the rate of severe hypoglycaemia, improved blood glucose control and restored awareness, when used in combination with education and frequent contact with the health service provider.
- The pharmacological studies were quite old and had low background rates of severe hypoglycaemia and so did not provide useful information on preventing impaired awareness of hypoglycaemia.
- Overall, the 43 studies were very diverse in type of intervention, number of participants (4 to 1,163) and length of follow-up (four weeks to almost five years). This diversity reduces the ability to apply these findings to people outside of the population and setting of each trial, i.e. to ‘generalise’ the findings.
What does current guidance say on this issue?
2015 NICE guidance on managing type 1diabetes recommends offering structured and validated education programmes on flexible insulin therapy, such as DAFNE, to all adults with type 1 diabetes. Awareness of hypoglycaemia should be assessed in adults with type 1 diabetes at each annual review and the Gold score or Clarke score used to quantify awareness of hypoglycaemia. For those where impaired awareness of hypoglycaemia persists, the guidance recommends structured education on avoiding and treating hypoglycaemia. As the next step, the guidance recommends offering continuous subcutaneous insulin infusion or insulin pump therapy and continuous blood glucose monitoring.
What are the implications?
This new systematic review adds weight to the 2015 NICE guideline and pathways. The review suggests that structured diabetes education like that described in the UK DAFNE programme (with or without psychoeducational and behavioural approaches) is useful in preventing symptomatic hypoglycaemia. For people who develop impaired awareness of hypoglycaemia the review increasing the intensity of interventions in a stepped approach seems logical. The NICE guideline costing statement estimates that offering a structured education programme such as DAFNE could save health services over £2,200 per person over ten years. Implementing the review’s findings could have a major positive impact on the lives of people with impaired awareness of hypoglycaemia, and reduce the costs of treating complications associated with it.
Yeoh E, Choudhary P, Nwokolo M, et al. Interventions that restore awareness of hypoglycemia in adults with type 1 diabetes: a systematic review and meta-analysis. Diabetes Care. 2015;38(8):1592-609.
DAFNE. DAFNE; 2015.
Diabetes UK. Diabetes: facts and stats. London: Diabetes UK; May 2015.
NICE. Type 1 diabetes in adults: diagnosis and management. NG17. London: National Institute for Health and Care Excellence; 2015.
NICE. Costing statement: type 1 diabetes in adults. Implementing the NICE guideline on type 1 diabetes in adults (NG17). London: National Institute for Health and Care Excellence; 2015.
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