Insulin vs pumps: The REPOSE trial findings deliver a verdict

The much-anticipated findings of the NIHR-funded REPOSE trial were published in The BMJ on 30 March. REPOSE was a cluster-randomised trial designed to investigate the ‘Relative Effectiveness of insulin Pump treatment Over multiple daily injections and Structured Education’.

In the UK, it is estimated that 6% of adults with type 1 diabetes use an insulin pump, compared to around 40% in the USA. Advocates for insulin pumps suggest that far more than 6% should be offered this management option in the UK (and elsewhere). The use of insulin pumps is expensive but can provide a more flexible way of delivering insulin. However, the weakness of existing evidence has been that, even in randomised controlled trials, people allocated to insulin pumps are likely to have received more training and attention than those using multiple daily injections (MDI). Thus, REPOSE set out to determine the relative benefit of pumps when people in both arms had equitable access to an evidence-based 5-day structured diabetes education program (i.e. DAFNE).

You can read the full details of the methods and results of REPOSE here. In total, 267 adults with type 1 diabetes were randomised to pumps or MDI, all of whom attended a DAFNE course in flexible insulin therapy. At 2 years post-course, both the pump and MDI groups experienced a clinically significant improvement in average blood glucose (HbA1c) and a significant reduction in severe hypoglycaemia rates. After adjusting for course, centre, age, sex and accounting for missing values, the between-group difference in HbA1c was non-significant (-0.24%), favouring pumps but not substantially. Most psychological outcomes showed no differences between groups but pump users experienced greater improvement in treatment satisfaction and some domains of quality of life (i.e. dietary freedom and daily hassle).

REPOSE is one of the most important studies to date in determining the relative effectiveness of insulin pump therapy in type 1 diabetes. It has a larger sample than all previous RCTs combined, a longer follow-up period (of 2 years) and, unlike most previous studies, has controlled for the effects of structured training and attention. Some might argue that the full potential of insulin pumps was not exploited, and that pump therapy is most suited to those who are prepared to engage fully in using its various advanced features. This study shows that this is not the majority of people, and some people were reluctant to participate in case they would be allocated to the pump therapy group. It is also important to note that only 1 in 4 study participants met the target HbA1c of 7.5% at 24 months, and only 3% met the new NICE target of 6.5% at 24 months – in both cases, this was regardless of allocation to pump or MDI. This suggests that neither structured education nor pump therapy is the sole solution, and there is an urgent need to investigate the psychological and behavioural barriers to achieving the biomedical targets known to minimise the risk of long-term complications.

Prof Simon Heller (University of Sheffield) who led the REPOSE trial, has commented that the results suggest that “ensuring people receive training to enable them to better manage their diabetes is likely to be more beneficial. Pumps may be useful in people who are highly engaged in their own management but find the limitations of insulin treatment prevent them achieving their glucose targets”. Andy Broomhead was a participant in the REPOSE trial. He commented: “Taking part in a DAFNE course as part of the REPOSE trial changed my life. DAFNE gave me the freedom, flexibility and confidence to manage my own type 1 diabetes confidently for the first time in a decade.”

So, what is the take-home message from this important study? Unsurprisingly, insulin pumps do not offer a magic bullet to ‘fix’ type 1 diabetes. On average, using an insulin pump offers greater flexibility, dietary freedom and more convenience to people with type 1 diabetes but, beyond this, it’s benefits for overall glycaemic control can largely be achieved with MDI following structured training. When insulin pump therapy works well its because the individual has made an active choice to manage their diabetes more intensively. MDI is not a second-rate alternative – and it may well be the treatment of choice for many people. A recent systematic review has shown that many people with type 1 diabetes do not take up structured diabetes training programs (such as DAFNE) because they do not see the benefit of attending, but many who have attended realise that “you don’t know what you don’t know” and say it has literally been life changing.

DAFNE is available to adults with type 1 diabetes across the UK and Ireland as well as in AustraliaNew ZealandKuwait and Singapore.

Heller SR, et al. (2017) Relative effectiveness of insulin pump treatment over multiple daily injections and structured education during flexible intensive insulin treatment for type 1 diabetes: cluster randomised trial (REPOSE)BMJ, 356:j1285.