A recent “Tools for Practice” from the fantastic people at the Alberta College of Family Physicians  asks the clinical question “Do glucagon like peptide 1 analogues ( GLP-1 ) improve patient orientated outcomes in type 2 diabetes?”

Diabetes is a key issue for primary care in New Zealand as it is all over the world and anything we can do to reduce the complications is causes has to be looked at seriously.

GPL-1 were apparently extracted from the saliva of Gila Monsters – lizards that eat once a month and need to rapidly increase their insulin production after eating. Administration in humans does the same thing – increasing endogenous insulin and suppressing glucagon. They also are reported to suppress appetite and are associated with a loss of weight of 1- 1.5 kg.

They cause nausea, vomiting and GI side effects and may be associated with pancreatitis.

The Tools for Practice article (albeit for other medications) show numbers needed to treat of 44-53 to show a minimal reduction in CVS risk of 1.3 – 1.6% – and a Number needed to harm of 16-33 for GI irritation, 112 for hypoglycaemia, 83 for retinopathy and gallbladder disease.

The article reviews the data on 2 GPL-1 that are not available here in this country, the only one that is available – Exanatide – is not subsidised – and a review in 2013 from the Best Practice Advisory Centre  and the Medsafe data sheet does not identify any significant reduction in cardiovascular disease outcomes but does find it reduces HBA1c% by around 10 mmol/l – and that it may be a useful 3rd line medication to consider adding to Metformin and a Sulphonyurea.

As the Canadians conclude “clinicians should prioritize pateint -orientated outcomes (like CVD) rather than sugars and microalbuminuria, and meta-analysis of small short trials can be misleading compared to large RCTs.”

I also think I would struggle to find a patient prepared to inject themselves twice a day and to pay for the privilege in my practice.

Conclusion – lots of limitations but something to be aware of.

Dr Jo Scott-Jones