Appeal type: Medical Necessity
Decision: Upheld

A 38-year-old female enrollee has requested the GlucoWatch Biographer for treatment of her type I diabetes mellitus.   Findings:  The physician reviewer found that the GlucoWatch is a useful adjunct to traditional invasive methods of self-monitoring of blood glucose to help detect patterns of hypoglycemia. Neither of the FDA-approved interstitial fluid sensors have achieved the reliability necessary for use as a glycemic alarm. Currently these devices are used to help manage  the insulin prescription by acting as a sort of glycemic Holter monitor. The sensors may be useful in picking up hypoglycemia retrospectively in patients who are unaware of their low blood sugars. However, the GlucoWatch cannot be used effectively as a monitoring device to avoid hypoglycemia due to the time delay between a decrease in glucose concentrations in the blood and the subsequent decrease in the interstitial fluid. Severe hypoglycemia may occur before the alarm goes off. Depending on the sensitivity of the settings,  there may be many false positive as well as false negative alarms. Patients must still check their blood glucose several times a day and continuously calibrate the watch with multiple finger-sticks. There is no doubt that wearing the GlucoWatch has improved detection of hypoglycemia in several studies. It is a useful adjunct to traditional methods of self-monitoring in patients with a documented history of multiple episodes of clinically significant hypoglycemia along with hypoglycemia unawareness. Still the GlucoWatch has several shortcomings as a hypoglycemia monitor. There is an eight to ten minute time lag between changes in venous and interstitial fluid glucose levels. Previous computer programs have also shown significant skips in the integrity of the data stream, possibly due to increased sweating during episodes of hypoglycemia. The sensitivity and specificity for detecting glucose values less than 70 mg/dl using various GlucoWatch programs is 38% to 75% and 97%, respectively. There is a positive predictive value of 57% and a negative predictive value of 94%. In a recent study to assess the usefulness of the GlucoWatch in detecting nocturnal hypoglycemia in children, the results were not impressive. One-third of the watches could not be calibrated. One-fourth of the watches were worn for the whole night. In this group, one-third of the readings were skipped because of data errors. One-half of the alarms were true positives and one-half of the alarms were false positives; there were no false negatives. The GlucoWatch is not experimental or investigational and has been approved by the FDA as a supplement for traditional finger-stick testing. There is a close correlation between the GlucoWatch detected values and  actual blood glucose values such that the device can be used retrospectively to detect trends and to modify the insulin prescription. Changes in the insulin regimen should not be based on any one particular watch reading. The DirectNet Study Group concluded that the GlucoWatch does not reliably detect hypoglycemia prospectively. The use of the watch in addition to standard glucose monitoring by finger-stick does not improve glycemic control or reduce the frequency of severe hypoglycemia. There are no records indicating the GlucoWatch is needed to detect patterns of hyper and/or hypoglycemia not evident with traditional testing.