ABVP roundtable regarding management of diabetic cats

Dear Editors – We are writing to comment on the recently published synopsis of a discussion among American Board of Veterinary Practitioners-certified veterinarians regarding the management of diabetic cats. ¹ The most disconcerting statistic is the high percentage – 15% – of cats alive for only up to 7 days after diagnosis of diabetes. The participants offered several reasons for this, including ketoacidosis and client circumstances. However, some veterinarians might project their previous frustrations with managing these patients onto the information provided to their clients of diabetic cats, rather than basing the discussion on scientific evidence, perhaps dissuading these clients from pursuing treatment and leaving euthanasia as the only option. ² Cats alive 8–89 days after initial diagnosis were still at risk of euthanasia, partly because of unmet client expectations of rapid resolution and reduced expense. Importantly, authors of recently published guidelines^3,4 for the management of diabetic pets do not include diabetic remission for cats as a goal, but roundtable participants reported diabetic remission as a desired goal. The management goals in the published guidelines are perhaps more achievable and realistic – to minimize or eliminate clinical signs, prevent insulin-induced clinical hypoglycemia, and mitigate the risk of or prevent complications.^3,4

Roundtable participants also discussed experiences, if any, with home blood glucose (HBG) testing, reporting that up to 40% of their clients continued HBG testing and providing data on the associated remission rates. Again, a contrast exists between the recommendation for HBG testing in the guidelines^3,4 and the mostly negative opinions expressed by roundtable participants. However, they reported no statistically significant difference in mean remission rates of patients from one participant who did not recommend home testing and of patients managed by the other participants (mean remission rates of 30.2% vs 24.1%, respectively). We reasonably hypothesize that because roundtable participants used various management strategies – including HBG testing – diabetic remission may not have been a suitable outcome measure for comparison. ⁵

Roundtable participants reported client resistance to HBG testing and speculated that client fear of disrupting the human–animal bond, inability to obtain a blood sample and lack of interest in HBG testing were possible reasons for this. Although HBG testing may not be appropriate for all situations, perceived or actual client resistance to HBG testing can be overcome, especially if the veterinarian truly believes that HBG testing optimizes clinical outcomes for diabetic cats and if the veterinary team provides confident support with ongoing, open communication. ² Authors of a 2004 study ⁶ reported that owners of diabetic cats readily accepted HBG testing because of reduced stress compared with in-hospital BG determination. Clients were also empowered to test at home in response to behavioral changes and then follow directions their veterinarians provided. Importantly, these clients believed HBG testing improved their confidence in managing their cats’ diabetes, which could also affect their willingness to continue management long term. ⁶

Interestingly, roundtable participants reported that HBG testing was positively correlated with survival over the 3 year study period; yet one participant who contributed about 25% of the cases analyzed, and who did not recommend HBG testing, reported the highest percentage of cats alive at the end of the data collection period at 72%, prompting the suggestion that HBG testing did not necessarily yield superior survival times. Yet, several factors may have affected these results, including length of time between initial diagnosis and end of the data collection period, size of each group (HBG testing vs no HBG testing), and circumstances in which participants who recommend HBG testing did so (ie, a selection bias towards recommending HBG testing to more severe or difficult to manage cases). Of note, statistical comparisons were not reported for this data. Although survival data can appear compelling, simply ‘being alive’ may not be the best metric to assess satisfactory patient management.^{2 –4}

Although clients may report that their diabetic cats are ‘doing well’ (ie, clinical signs of diabetes are minimal or not apparent at home), asymptomatic cats can still have unacceptably high blood glucose concentrations. ⁷ Client observations are critical, but most clients need training and experience to hone these skills. Objective data such as body weight and BG concentrations are vital; the latter to prevent the development of adverse consequences of hyper- and especially hypoglycemia.^3,4,7 Roundtable participants reported BG concentrations ‘not uncommonly’ between 400 and 600 mg/dl (22.2–33.3 mmol/l) for cats with minimal or no clinical signs. One participant reported spot-checking in-hospital BG about 12 h post-insulin administration as standard protocol. However, a single BG concentration may be high because of incorrect insulin dose and/or stress.^3,8 The time of peak insulin effect and associated BG concentration, duration of insulin action, and average BG concentration over time can be determined from multiple BG determinations over 8–12 h and accurate measurement of these parameters is strongly facilitated by HBG testing.^3,4,7

Risk factors for diabetic comorbidities vary depending on cat age at the time of diabetic diagnosis. ² Although peripheral neuropathy is the most frequently cited long-term consequence of poor glucose regulation,^{2 –4,7} because of the relatively short life span of feline diabetics compared with human diabetics, the long-term consequences of unregulated diabetes are not as widely recognized in cats.^2,7 Additionally, prospective studies to assess the long-term consequences of poor diabetic regulation in cats are lacking.

Although roundtable participants acknowledged the limitations of the data presented throughout the publication, perhaps the most important outcome of the discussion was to begin a dialogue between veterinarians, hopefully prompting them and industry stakeholders to continue to compare different management strategies for diabetic cats and strive for improved patient outcomes. A single management strategy did not emerge as superior; therefore, HBG testing remains a recommended management strategy and its benefits – to the veterinarian in partnership with the client and to diabetic cats – are widely accepted.^{2 –4,6,7}

Matthew Krecic, DVM, MS, MBA, DACVIM Annette Litster, BVSc, PhD, FACVSc (Feline Medicine), MMedSci (Clin Epi)