Recent studies and a widely-publicized report from NPR have re-opened the long-running conversation about the cost-effectiveness and benefits of diabetes safety alert dogs.

The promised offered by these service animals is similar to the benefit for people with blindness or other disabilities — they help them navigate life safely and effectively, as well as providing companionship. Since 2003, dogs have been officially used as a kind of early detection system for blood sugar — hypoglycemia in particular, which presents the most immediate threat to people with type 1 diabetes.

This benefit, however, comes at a cost – a substantial financial one, in fact. As NPR reports, certified diabetes dogs can cost between $15,000 and $25,000 up front, in addition to the cost of care and feeding. For that kind of money, it’s important to establish what you’re getting, and how the cost-benefit analysis works out.

Do diabetes support dogs work as advertised?

The answer to the question, “do diabetes support dogs work” boils down to this: sometimes, but not always. Before reliable continuous glucose monitoring (CGM) technology became widespread and relatively affordable, it made sense that people would employ any available method to detect those dangerous low blood sugars before they resulted in hospitalization, or worse.

For parents of children with type 1 diabetes, the service dogs can also provide an invaluable social function, providing a sense of companionship and safety. In a very real sense, they can make diabetes feel less like a tragic condition or an “enemy” and more a part of the patient’s lives.

In terms of actual efficacy at detecting those critical low blood sugars, however, the track record of diabetes service dogs is uneven. NPR cited a 2017 study led by University of Virginia psychologist Linda Gonder-Frederick, in which scientists looked at 7 adults and 7 children with type 1 diabetes using diabetes alert dogs over a period of at least 6 months. At the same time, the study participants were equipped with masked CGMs and recorded the warnings their dogs provided in paper and electronic records.

The results showed a great deal of variation across the population, with the dogs on average detecting 35.9% of low blood sugar events and 26.2% of high blood sugar events accurately. Perhaps unsurprisingly, these numbers dropped even further during sleep, where the dogs only detected 22.2% of lows and 8.4% of highs. One of the downsides of living animals as blood sugar detectors is, of course, that they need sleep as well.

Overall, the scientists found, 3 out of the 14 dogs performed better than random chance guessing during waking hours, and only 1 of 14 performed better at night.

“Overall, they really were not that reliable or accurate,” Gonder-Frederick told NPR.

Making an educated assessment of diabetes awareness dogs

Is the conclusion, then, that diabetes support dogs are never worth it? Not quite.

Professional trainers of diabetes awareness dogs maintain that if their dogs are not correctly alerting owners of highs and lows, they can take them back to be retrained or, if necessary, replaced. One of the challenges they face is the difference between training conditions and real-world noise, distraction, and stress.

Edwin Peeples, the co-owner of Diabetic Alert Dogs of America, told NPR that he’d trained more than 700 support animals so far, with a client satisfaction rate 90%. He maintains that most of the above issues can be addressed through training, though some former clients contest that.

Despite the evidence that support and awareness dogs might not be performing as effectively on a scientific basis, there is a correlation between them and improved outcomes for people with type 1 diabetes. Gonder-Frederick suggested in her interview that they may simply increase the amount of attention that people pay to their own diabetes, as the dog provides a more positive or affirming reminder than they’d otherwise have.

For the owners of the dogs, it remains a complicated — and emotional – decision. After all, they become more than simple service animals — they are pets, friends, and members of family. In some cases, the owners of these service dogs have chosen to keep them and even attempt retraining themselves, whether or not they’re able to perform precisely as they are meant to.