Managing type 1 diabetes is a high-level balancing act – too much or too little insulin is a bad thing, resulting in blood sugar levels deviating from a narrow range with potentially serious consequences on either side. Many diabetics choose to use insulin pumps to make it all easier to manage, but as the recent recall of insulin pump software by the US Food and Drug Administration shows, the technology is not foolproof.
Thankfully, the scope of the recall is very limited. It is targeted at users of the Tandem T:Slim X2 insulin pump and the companion application running exclusively on iOS devices. The purpose of the mobile app is to run on the user's phone to monitor and control the pump. The pump itself is a small, rechargeable device that users often wear on their belt or in a pocket that provides a slow, steady flow of insulin during the day, as well as larger bolus doses to replenish meals .

But version 2.7 of the t:connect mobile app may crash unexpectedly, and on iOS devices, causing the OS to constantly relaunch it. Each time this is done, the app attempts to reconnect to the pump via Bluetooth, which ultimately drains the battery in the pump. Once the battery drains, no more insulin can be delivered, potentially leading to a condition called hyperglycemia (“hyper” means excess, “gly” means sugar, and ” “Aemia” means the presence of excess sugar in the blood.
Untreated hyperglycemia can develop into a much more serious condition called diabetic ketoacidosis, which can lead to coma and death. Thankfully, no one has been harmed that way by this bug, but the FDA has received over 200 reports of injuries, so it has been recalled. Tandem sent a notice to all affected customers in March asking them to update their apps, but it's still possible that some users may not have received the message.
In addition to the human cost of this bug, there is a lesson here about software design and unintended consequences. While it intuitively seems like a great idea to automatically relaunch a crashed app, especially one with a critical life-saving function, in hindsight, the better approach is to simply go into a safe mode and let the user restart. May need to be alerted with an alarm. It's a lesson we've learned from space exploration, and it appears to apply here too.
Images: AdobeStock, Tandem Diabetes