Evolution of analytical performance in portable glucose meters in the last decade.

OBJECTIVE: To assess and compare the technical accuracy of portable glucose meters during the last decade. RESEARCH DESIGN AND METHODS: One-thousand preprandial (pre) and postprandial (post) capillary whole-blood glucose values measured with meters owned mainly by diabetic patients were compared with a single laboratory method yearly from 1989 to 1999. A total of 21,950 capillary measurements and their corresponding laboratory reference values were analyzed at our clinic. RESULTS: The lowest mean absolute difference was found in 1989 (pre: 2 +/- 22 mg/dl, post: 9 +/- 31 mg/dl) (mean +/- SD). The highest mean absolute difference was observed in 1993 (pre: 31 +/- 33 mg/dl) and 1996 (post: 50 +/- 35 mg/dl). The highest mean relative deviation was observed in 1990 (pre: 16.4%) and 1996 (post: 20.6%). The highest percentage of readings that were within a 5% deviation limit were observed in 1998 (pre: 44.5%) and in 1997 (post: 36.7%). Based on blood glucose levels within +/-5 and +/-10% of laboratory values, the technical accuracy of meters was similar for 1989 and 1999 (P = 0.27 and 0.52, respectively). The percentage of pre values in zone A of Clarke's error grid analysis was >90% in 1989, 1997, 1998, and 1999. CONCLUSIONS: The analytical performance of glucose meters decreased between 1990 and 1996 but was restored between 1997 and 1999. Nevertheless, our data suggest that the technical accuracy of glucose meters has not significantly improved during the last decade. Complementary studies taking into account the preanalytical improvements of the recent meters, as well as their calibration method, appear necessary.

Clinical performance of CGMS in type 1 diabetic patients treated by continuous subcutaneous insulin infusion using insulin analogs.

OBJECTIVE: Performance criteria have been established for in vitro blood glucose monitoring, particularly for the self-monitoring of blood glucose using glucose meters. Devices intended for use in the future, such as the continuous glucose monitoring system (CGMS), should satisfy similar criteria, particularly in diabetic patients under intensive therapy. RESEARCH DESIGN AND METHODS: The analysis was conducted on 18 type 1 diabetic patients (not controlled, HbA(1c) >7.5%) treated by external pump using insulin analogs. Each patient received a glucose sensor for 3 days during his/her hospitalization and was instructed in its operation. Medtronic criteria were used to determine the accuracy of the CGMS. In addition, the data were analyzed according to American Diabetes Association (ADA) criteria, Clarke Error Grid analysis, and method of residuals, with the glucose oxidase method using a Beckman analyzer used as the reference method. Specificity and sensitivity were evaluated from the viewpoint of accuracy in the detection of hypoglycemia. For nine patients, two glucose sensors were simultaneously inserted into an abdominal site to determine the reproducibility of the system. RESULTS-Among the 33 glucose sensors inserted, 6 (18%) were nonfunctional. The mean duration of CGMS recording was 63 +/- 12 h. From all of the 692 sets of data that paired glucose readings and CGMS, the coefficients of correlation ranged from 0.87 to 0.92 and the mean absolute error ranged from 12.8 to 15.7%. The time experienced in hypoglycemia (<55 mg/dl) was reported at 86 +/- 62 min/day. Only 39% of the CGMS values satisfied the ADA precision criteria to within +/-10%, and 19% of these values satisfied the future ADA precision criteria of accuracy to within +/-5%. The means of difference method showed that the CGMS slightly underestimated the plasma glucose values (mean = -12 mg/dl). Error grid analysis showed only 77% of the glucose sensor values were in zone A, and 98.9% were in zones A and B. Two values fell in zone C and a single value fell in zone D. The sensitivity and specificity of the CGMS to detect hypoglycemia were 33 and 96%, respectively. A total of 6666 paired sensor values were recorded with a coefficient of correlation of 0.84 with a coefficient of variation of 8.25%. CONCLUSIONS: CGMS could be useful in routine clinical practice to provide much more information on the glucose profile than intermittent self-monitoring of blood glucose (SMBG). However, CGMS cannot be used as a replacement for glucose meters because it does not satisfy the conventional performance goals set down for in vitro glucose measurements and could therefore lead to clinically incorrect treatment decisions.

[Continuous glucose monitoring, a guide to reading the results and patient education]. / Mesure continue du glucose, guide de lecture des résultats et éducation du patient.

Conventional self-monitoring of blood glucose (SMBG) presents a certain number of limits. In particular, it cannot provide information on events occurring some time before the self-monitoring. Various systems for the continuous monitoring of glucose levels have therefore been developed for use in outpatient clinics or at home. When being used at home, nursing staff must pay particular attention to the therapeutic education of the patient.

[Insulin injection technique, practices observed by patients and nurses]. / La technique d'injection de l'insuline, pratiques observées par les patients et les infirmières.

A study was carried out in 2008-2009 on the practices of patients with diabetes with regard to insulin self-injection techniques. The results highlight in particular the importance of patient education.