Many people with diabetes may be unwittingly storing their insulin incorrectly due to fluctuating temperatures inside their kitchen fridge, new research has found.
Insulin must be stored within a certain temperature range in order to retain its potency. Many people who need it to control their diabetes keep it in their fridge at home for several months before using it.
“Even gradual loss of potency introduces unnecessary variability in dosing”
However, a study by researchers from Germany suggests storing insulin in an ordinary kitchen fridge may harm quality because of changes in temperature.
The study saw 388 diabetes patients from the US and Europe place temperature sensors next to insulin in their fridge or the bag they carry their insulin around in when out and about.
The temperature was recorded automatically every three minutes for an average period of 49 days.
Analysis of temperature logs found 79% deviated from the recommended range for storing insulin - between 2 and 8 degrees Celsius in the fridge or 2 to 30 degrees C in a pen or vial.
The findings, presented at the European Association for the Study of Diabetes’ annual meeting in Berlin, show insulin stored in the fridge was outside the recommended temperature range 11% of the time – equivalent to two hours and 34 minutes per day.
In contrast, insulin carried by patients was only outside the recommended range for around 8 minutes per day.
Freezing was found to be a big problem with 17% of sensors measuring temperature below 0 degrees C – equivalent to three hours per month on average.
The results suggest keeping insulin in a domestic fridge may affect how well it works, potentially posing a risk to users, the research team concluded.
“Long-term storage conditions of insulin are known to have an impact on its blood-glucose lowering effect,” said lead researcher Dr Katarina Braune, from the Charité university hospital in Berlin, who urged insulin-dependent diabetics to check the temperature inside their fridge.
Precise dosing was incredibly important for those who rely on insulin, she stressed.
“For people living with insulin-dependent diabetes who take insulin several times a day via injections or continuously administer insulin with a pump, precise dosing is essential to achieve optimal therapeutic outcomes,” she said. “Even gradual loss of potency introduces unnecessary variability in dosing.”
However, she added more research was needed to explore the extent to which keeping insulin in a fridge at home had an impact on its effectiveness and patient outcomes.