A year ago, I wrote Diabetes Alert Dogs Are An Unproven Concept . A recent brief report in Diabetes Care, Diabetic Alert Dogs: A Preliminary Survey of Current Users doesn’t change my mind. As I previously pointed out, there aren’t any published peer-reviewed studies to support the claims that DADs (diabetes alert dogs) are useful, nor is there any information about how or why these dogs could react to changing glucose levels.
The latest report is a small survey of owners of diabetes alert dogs. The results are glowing: “Respondents reported signiﬁcant decreases in the frequency of severe … and moderate … hypoglycemia since DAD placement, as well as glycosylated hemoglobin levels.”
But there are huge problems with this report. First of all, there’s nothing in the discussion as to how the survey owners were identified, other than that they were users of the DAD-training company run by one of the authors. Did the survey invitation go only to successful users? Unless the survey went out to everyone who had ever used their dogs (including those whose dogs might have unsuccessful when placed in the home), and unless humongous efforts were made to assure near-100% response rates, we don’t know what responses non-inquired or non-responders might have provided.
Second, this was an on-line survey, so reported data about rates of hypoglycemia and changes in A1C couldn’t be verified, and hence are completely suspect. And the report that there were changes in A1C are not verified by including the pre- and post- A1C levels. Furthermore, why would one even want a decrease in A1C if the patient was already having substantial problems with hypoglycemic events?
Next, the survey itself is not included in the report, nor a hyperlink to where it might be found. Depending on the wording of the questions, it might have biased results: imagine if it included highly biased questions of the “when did you stop beating your wife” variety!
Finally, as the authors point out, “prospective studies of larger numbers of DAD owners, with objective measures to assess DAD accuracy and clinical outcomes are needed.” I completely agree.
As I’ve said before: Until a well-designed study is carried out, presumably with the patients wearing continuous glucose monitors (CGM) so glucose levels can be continuously monitored, we won’t know. With CGM, one would easily be able to determine the percentage of lows that caused the animals to react, and whether they sense and react to changes in blood sugar. Another benefit of CGM is that the number of times the dogs react when the sugar is normal and stable (false positives) can be ascertained. Until we know such information from a well-designed and published study, it’s risky to assume that dogs are more reliable than CGM.
I know that the reader might surmise that I seem opposed to the use of DADs, and I assume some people who are true believers will denounce my lack of belief in the power of dogs to smell low glucose levels (or whatever it might be that they might be sensing). Maybe I'm suspicious because there are so many wide-eyed media reports of success when there's very little to substantiate the claims in these stories. Maybe it's the horrendous costs of "training" DADs. But mainly it's because there's so little data to support the validity of the concept, and no clear theories on how dogs might recognize changes in glucose.
It's still an unproven concept.