LGS - a new diabetes concept as well as a new acronym   (March 5, 2012))

"Low Glucose Suspend" (LGS) is a insulin-pump-related concept that you should be hearing more about as time goes by.

Ever since insulin pumps were developed, over thirty years ago, one of the recurring concerns has been the scenario that the pumper is either asleep or unconscious with a low sugar level - and the pump keeps pumping more insulin into them. Clearly, there needs to be someone or something that would interrupt the flow of insulin, and until recently, there was no practical way for the pump to shut itself off (other than waiting for it to eventually run out of insulin or battery power!).

However, with the recent development of continuous glucose monitoring (CGM) and the subsequent integration of the CGM readouts into an insulin pump by one of the pump manufacturers (Medtronic), it was time to develop a shutoff feature for insulin delivery based on low glucose readings. And Medtronic did so: their pump with a shutoff is called the Paradigm Veo and has been available in the UK since 2009.

How does LGS work in the Veo? Per their description at the Medtronic UK website, "Imagine, for example, that your glucose level is beginning to fall. The Paradigm Veo can recognise this using the CGM function of the pump and will sound an alert to warn you. You can then act on this to prevent a hypoglycaemic event. However, if you have not responded to this alert and the CGM recognises a dangerously low glucose level, another warning will sound. If, however, you are unable to respond to the warning for some reason, the Paradigm Veo acts quickly to suspend insulin delivery for two hours, helping to prevent the hypoglycemic event from becoming any more harmful."

Does the concept work? A study was published in Diabetes Care in September 2011, Insulin Pump Therapy With Automated Insulin Suspension in Response to Hypoglycemia which concluded that "Use of an insulin pump with LGS was associated with reduced nocturnal hypoglycemia in those at greatest risk and was well accepted by patients."

Recently a study called ASPIRE (Automation to Simulate Pancreatic Insulin REsponse) has published the results of the initial phase of the study (in a clinic setting), and, to quote Medtronic's press release, the researchers found "a 19% reduction in time spent below the low glucose threshold in patients using the MiniMed Paradigm System featuring Low Glucose Suspend (LGS) automation, compared to conventional pump therapy." There is nothing in the abstract, press release, nor the accompanying editorial commentary that implies there were any adverse events observed. The authors concluded "Automatic suspension of insulin delivery significantly reduced the duration and severity of induced hypoglycemia without causing rebound hyperglycemia."

The second phase of the ASPIRE study, involving in-home use, is now underway. Hopefully it will be completed soon, and seems likely to add to the documentation that LGS works. Assuming the ASPIRE study continues to show positive results, then LGS should soon be ready for approval in the USA.