Heating Up: Insulin, Extreme Temperatures and Climate Change

-Daniel Pereira

One of the first things many diabetics learn about insulin is that it’s far from shelf-stable. Our life-saving drug needs to be stored within a relatively narrow range of temperatures so that the proteins don’t denature and unravel, rendering them useless.

If you’re picking up your insulin prescription at a pharmacy and bringing it straight home for refrigerator storage, this doesn’t present much of an issue – once opened, most people with type 1 diabetes will use up a vial of insulin before it breaks down. It’s not that simple for people around the country, though – and indeed around the world.

For some, continuous electricity and refrigeration is far from guaranteed. Regular brownouts and blackouts threaten the continuous supply needed to keep insulin at a stable temperature, forcing many people with diabetes to utilize generators, ice packs and other measures to keep insulin at the right temperature.

There are other, more prosaic challenges and problems, as well. Mail-order pharmacy has made stocking up on critical meds much easier for people with diabetes around the world, but it also presents some unique challenges for those in less-forgiving climates. Insulin left out on a hot porch or in a freezing-cold mailbox might not be fit for purpose by the time it’s brought inside.

Safe in the fridge? Don’t count on it

In fact, even refrigerated storage might not be reliable enough to count on in certain circumstances. A paper presented by Katarina Braune, MD, from Charité-Universitaetsmedizin Berlin, Germany found that insulin stored in refrigerators experiences far more extreme temperature variations than expected. The paper was presented at the 54th European Association for the Study of Diabetes (EASD) Annual Meeting.

“Nearly every dataset relating to fridge storage showed excursions from the recommended range that are below 2° C [35.6° F] and above 8° C[46.4° F], and even some excursions below 0° C[32.0° F]. We were surprised that every dataset showed this pattern,” Dr. Braune said at the press conference attended by Medscape. “Our results show that refrigerated insulin was exposed to more temperatures out of range than insulin that is carried around [on the person].”

Insulin that gets too hot or too cold becomes less effective at lowering blood sugars – if it’s frozen, it becomes completely useless.

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“Based on these findings, it might also be recommended not to store insulin in the butter or dairy compartment nor in the vegetable drawer, but rather in the middle shelf or the meat drawer,” Bernhard Gehr, MD, a senior diabetologist in Germany, told Medscape.

Changing climate and global considerations

Of course, the potential problems and consequences of temperature variability are rapidly becoming a bigger issue around the globe as the effects of climate change disrupt weather systems and patterns.

While it’s hard to make specific predictions, most climate scientists agree that climate change leads to larger extremes and more volatility in regional temperatures and conditions, whether it’s record-breaking heat waves in Australia, cyclones in Mozambique, or even blizzards across the Eastern seaboard.

With more and more people receiving critical medications from mail-order pharmacies,quickly changing temperatures can have life-threatening consequences, as NPR reported in January.

According to a study by IQVIA’s Institute for Human Data Science, a quarter of all prescription spending goes through mail-order pharmacies now. This shift is driven by factors that are in equal part financial (it’s much cheaper for pharmacy benefit managers to ship drugs directly rather than dealing with retail logistics), and many patients appreciate the convenience of receiving up to 90 days supply of their medications by mail.

The companies handling these drugs face serious logistical challenges, including temperature monitoring and prediction to include special packaging or additional ice packs to protect compounds such as insulin.

“If there’s an extreme heat situation where a product is going into 100-plus degree weather, the system will tell the technician to add an extra ice pack,” Alysia Heller, a lead pharmacist for OptumRX, told NPR. “[It’s] because we’ve monitored the zip code and the weather in that area.”

As climate change makes weather patterns harder to predict and increases the spikes and troughs during extreme conditions, it will become harder and riskier for both patients and providers to trust that the vital medicines they need will be OK sitting on the front porch.

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