• Open Access

Comparison of a Continuous Glucose Monitoring System with a Portable Blood Glucose Meter to Determine Insulin Dose in Cats with Diabetes Mellitus


Corresponding author: E. Zini, Clinic for Small Animal Internal Medicine, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland; e-mail: ezini@vetclinics.uzh.ch.



The continuous glucose monitoring system (CGMS) Guardian REAL-Time® allows the generation of very detailed glucose profiles in cats. The performance of CGMS to generate short-term glucose profiles to evaluate treatment response has not been yet evaluated in diabetic cats.


Analysis of glucose profiles generated using the CGMS produces insulin dose recommendations that differ from those of profiles generated using the portable blood glucose meter (PBGM) in diabetic cats.


Thirteen client-owned diabetic cats.


Prospective, observational study. Simultaneous glucose profiles were generated over an 8-10 hour period using the CGMS, blood glucose concentration was measured every 2 hours with the PBGM. Profiles were submitted to three internal medicine specialists who used them to determine the insulin dose. Differences between insulin doses deduced from paired profiles were compared. Percentages of nadirs recorded with the CGMS that were lower, higher, or equal to those derived with the PBGM were calculated.


Twenty-one paired glucose profiles were obtained. There was no difference of insulin doses based on CGMS and PBGM profiles (median 0 U; range: −1 to +0.5). Treatment decisions did not differ among investigators. Compared with the observed PBGM nadir, the CGMS nadir was lower, higher, or equal in 17, 2, and 2 of 21 cases, respectively.

Conclusions and Clinical Importance:

Adjustments in insulin dose based on glucose profiles generated with the CGMS are similar to those based on the PBGM. The common occurrence of lower nadirs recorded with the CGMS suggests that this device detects hypoglycemic periods that are not identified with the PBGM.