System Accuracy Assessment of a Combined Invasive and Noninvasive Glucometer.

BACKGROUND: The pain associated with pricking the fingertip for blood glucose self-testing is considered to be a major burden in diabetes treatment. This study was performed to evaluate the system accuracy of the invasive TensorTip Combo Glucometer (CoG) device component in accordance with ISO15197:2015 requirements and to explore the accuracy of the noninvasive tissue glucose prediction component. METHODS: One hundred samples were obtained from people with type 1 and type 2 diabetes and healthy volunteers (43 females, 57 males; age: 53 ± 16 years), with glucose distribution as requested by the ISO standard. Three strip lots were tested twice by healthcare professionals in comparison to YSI 2300 Stat Plus reference method followed by a noninvasive tissue glucose reading (NI-CoG). Mean Absolute (Relative) Difference (MARD) was calculated and a consensus error grid (CEG) analysis was performed. RESULTS: The ISO system accuracy criteria were met with the invasive strip technology by 586/600 of the data points (97.1%) and for each strip lot separately. All invasive results (100%) were within CEG-zone A and total MARD was calculated to be 7.1%. With the noninvasive reading, 99% of raw data points were in A + B (91.1% and 7.8%), and the total MARD was calculated to be 18.1%. DISCUSSION: The invasive component of the CoG device was shown to be in full compliance with the current ISO15197 criteria. Good results were also obtained with the NI-CoG tissue glucose prediction. This noninvasive technology would potentially be suitable for frequent pain-free glucose monitoring in many people with diabetes.

System Accuracy Assessment of a Blood Glucose Meter With Wireless Internet Access Associated With Unusual Hypoglycemia Patterns in Clinical Trials.

BACKGROUND: In recent randomized clinical trials, an unusual reporting pattern of glycemic data and hypoglycemic events potentially related to an internet enabled blood glucose meter (MyGlucoHealth, BGM) was observed. Therefore, this clinical study was conducted to evaluate the system accuracy of the BGM in accordance with the ISO15197:2015 guidelines with additional data collection. METHODS: To investigate system accuracy, 10 of 3088 devices and 6 of 23 strip lots, used in the trials, were selected by a randomization procedure and a standard repeatability assessment. YSI 2300 STAT Plus was used as the standard reference method. The samples were distributed as per the ISO15197:2015 recommendations with 20 additional samples in the hypoglycemic range. Each sample was tested with 6 devices and 6 strip lots with double determinations. RESULTS: Overall, 121 subjects with blood glucose values 26-423 mg/dL were analyzed, resulting in 1452 data points. In all, 186/1452 readings (12.8%) did not meet the ISO acceptance criteria. Data evaluated according to the FDA guidelines showed that 336/1452 (23.1%) readings did not meet the acceptance criteria. A clear bias toward elevated values was observed for BG <100 mg/dL (MARD: 11.0%). CONCLUSIONS: The results show that the BGM, although approved according to standard regulatory guidelines, did not meet the level of analytical accuracy required for clinical treatment decisions according to ISO 15197:2015 and FDA requirements. In general, caution should be exercised before selection of BGMs for patients and in clinical trials.

Evaluation of a New Noninvasive Glucose Monitoring Device by Means of Standardized Meal Experiments.

BACKGROUND: Frequent blood glucose readings are the most cumbersome aspect of diabetes treatment for many patients. The noninvasive TensorTip Combo Glucometer (CoG) component employs dedicated mathematical algorithms to analyze the collected signal and to predict tissue glucose at the fingertip. This study presents the performance of the CoG (the invasive and the noninvasive components) during a standardized meal experiment. METHODS: Each of the 36 participants (18 females and males each, age: 49 ± 18 years, 14 healthy subjects, 6 type 1 and 16 type 2 patients) received a device for conducting calibration at home. Thereafter, they ingested a standardized meal. Blood glucose was assessed from capillary blood samples by means of the (non)invasive device, YSI Stat 2300 plus, Contour Next at time points -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, and 180 minutes. Statistical analysis was performed by consensus error grid (CEG) and calculation of mean absolute relative difference (MARD) in comparison to YSI. RESULTS: For the noninvasive (NI) CoG technology, 100% of the data pairs were found in CEG zones A (96.6%) and B (3.4%); 100% were seen in zone A for the invasive component and Contour Next. MARD was calculated to be 4.2% for Contour Next, 9.2% for the invasive component, and 14.4% for the NI component. CONCLUSIONS: After appropriate individual calibration of the NI technology, both the NI and the invasive CoG components reliably tracked tissue and blood glucose values, respectively. This may enable patients with diabetes to monitor their glucose levels frequently, reliably, and most of all pain-free.

Comparison of the dose accuracy of prefilled insulin pens.

BACKGROUND: Prefilled insulin pens have become a convenient and accurate way for diabetes patients to inject insulin. Their ease of use has helped to reduce the resistance of patients with type 1 diabetes and type 2 diabetes in the United States and Europe toward initiation of insulin therapy. This study compared the dosing accuracy of two prefilled insulin pens (the SoloStar((R)) from Sanofi Aventis, Berlin, Germany, and the Next Generation [NG] FlexPen((R)) from Novo Nordisk, Mainz, Germany). METHODS: The dosing accuracy was tested for both pens with x 24 10 international units of insulin (IU) and 9 x 30 IU injection volumes to investigate whether the pens comply within the acceptable International Organization for Standardization (ISO) limits of 10% (±1 IU) for 10 IU and 5% (±1.5 IU) for 30 IU. The doses were applied each with a new needle strictly according to the instructions for use of the pen manufacturers. A sensitive pharmaceutical balance was used for the assessment of the applied volumes, and the results were corrected for the specific density of the insulin formulations. We used 18 insulin pens (from two different production lots each) for the two volumes, respectively, resulting in a total of 432 doses per pen with 10 IU and 162 doses per pen with 30 IU. RESULTS: Both pens showed a very good performance, which was better for the 10 IU dose than in comparative previous studies. The NG FlexPen (mean absolute percent deviation 10 IU/30 IU: 1.63 ± 0.84%/1.23 ± 0.76%) was even more accurate than the SoloStar (2.11 ± 0.92%/1.54 ± 0.84%, p < .001/p < .05 versus the NG FlexPen). Only 0.2% of the doses were outside the ISO limit at 10 IU, with the NG FlexPen (0.6% at 30 IU). The corresponding figures for the SoloStar were 0.4% and 1.8%, respectively. CONCLUSIONS: A direct head-to-head comparison of the two prefilled insulin pens with a standardized protocol resulted in a more stable dosing accuracy of both pens as compared to previous investigations. In this investigation, the NG FlexPen was more accurate than the SoloStar at both tested doses.

Differences in the dose accuracy of insulin pens.

BACKGROUND: Modern insulin injection pens provide a convenient and accurate way for diabetes patients to inject insulin. They have widespread use among children and adults with type 1 and type 2 diabetes in the U.S. and Europe. This study compared the dosing accuracy of four commonly available insulin pens (OptiClik and SoloSTAR from sanofi-aventis, FlexPen from Novo Nordisk, and HumaPen LUXURA from Eli Lilly). METHODS: The dosing accuracy was tested for all pens with 24 x 10 IU and 9 x 30 IU injection volumes to investigate whether the pens complied with the acceptable International Organization for Standardization (ISO) limits of 10% (+/- 1 IU) for 10 IU and 5% (+/- 1.5 IU) for 30 IU. The doses were each applied with a new needle strictly according to the instructions for use by the pen manufacturers. A pharmaceutical balance was used for the assessment of the applied volumes, and the results were corrected for the specific density of the insulin formulations. Four insulin pens (two each from different production lots) were used for each of the two volumes, resulting in a total of 192 doses per pen with 10 IU, and 72 doses per pen with 30 IU. RESULTS: FlexPen (mean absolute percent deviation for 10 IU and 30 IU: 1.64 +/- 0.84% and 0.83 +/- 0.26%, respectively) and HumaPen LUXURA (1.10 +/- 0.20% and 0.62 +/- 0.19%; not significant versus FlexPen for both doses) were more accurate than the OptiClik (4.78 +/- 3.31% and 2.97 +/- 2.48%, p <.01) and the SoloSTAR (2.61 +/- 0.92% and 1.70 +/- 0.84%, p <.05). While 6.8% of doses were outside the ISO limit at 10 IU with OptiClik (13.9% at 30 IU), the corresponding figures were 0.5% and 4.1%, respectively, for SoloSTAR. No doses outside the ISO limits were seen with FlexPen or HumaPen LUXURA at 10 IU and only one 30 IU dose (1.4%) was outside the limit for FlexPen. CONCLUSIONS: A direct head-to-head comparison of four insulin pens with a standardized protocol resulted in a more stable dosing accuracy of the FlexPen and the HumaPen LUXURA in comparison to the OptiClik and SoloSTAR. Even though all insulin delivery systems undergo rigorous testing before being approved for sale, there may be reasons to be attentive to the performance of the devices in practical use.