Shortfalls of the use of HbA1C-derived eAG in older adults with diabetes.

AIMS: The hemoglobin HbA1C (HbA1C) value, translated into estimated average glucose concentration (eAG), is commonly used to assess glycaemic control and manage treatment regimens in people with diabetes. However, the relationships among HbA1C-derived eAG, and mean glucose concentration derived from continuous glucose monitoring (CGM) in different populations have not been well studied. We examined this relationship in older people with diabetes and compared the results to those currently used in clinical practice. METHODS: Data from three studies evaluating CGM in older adults (≥70 years of age), with stable glycaemic control were analyzed retrospectively. Mean glucose and mean amplitude of glucose excursion (MAGE) were calculated from CGM data and correlated with HbA1C and HbA1C-derived eAG using the ADAG study formula. RESULTS: HbA1C and CGM data were analyzed from 90 patients with mean age 76±5 years, HbA1C 7.9±1.2% (63±13 mmol/mol) and 77% with Type 2 diabetes. The HbA1C and HbA1C-derived eAG correlated significantly with CGM-measured mean glucose (r(2)=0.30, p<0.0001) and MAGE (r(2)=0.16, p=0.00013) in this population and all its subgroups, but the slopes of the relationship between HbA1C and eAG or CGM-measured mean glucose were significantly different. CONCLUSIONS: HbA1C-derived eAG values may not accurately reflect CGM-measured mean glucose or MAGE in older adults with diabetes. Wide glucose excursions should be considered and HbA1C should be interpreted cautiously when making treatment changes based on HbA1C.

Evaluation of JPEG and JPEG2000 compression algorithms for dermatological images.

BACKGROUND: Some image compression methods are used to reduce the disc space needed for the image to store and transmit the image efficiently. JPEG is the most frequently used algorithm of compression in medical systems. JPEG compression can be performed at various qualities. There are many other compression algorithms; among these, JPEG2000 is an appropriate candidate to be used in future. OBJECTIVE: To investigate perceived image quality of JPEG and JPEG2000 in 1 : 20, 1 : 30, 1 : 40 and 1 : 50 compression rates. METHODS: In total, photographs of 90 patients were taken in dermatology outpatient clinics. For each patient, a set which is composed of eight compressed images and one uncompressed image has been prepared. Images were shown to dermatologists on two separate 17-inch LCD monitors at the same time, with one as compressed image and the other as uncompressed image. Each dermatologist evaluated 720 image couples in total and defined whether there existed any difference between two images in terms of quality. If there was a difference, they reported the better one. Among four dermatologists, each evaluated 720 image couples in total. RESULTS: Quality rates for JPEG compressions 1 : 20, 1 : 30, 1 : 40 and 1 : 50 were 69%, 35%, 10% and 5% respectively. Quality rates for corresponding JPEG2000 compressions were 77%, 67%, 56% and 53% respectively. CONCLUSION: When JPEG and JPEG2000 algorithms were compared, it was observed that JPEG2000 algorithm was more successful than JPEG for all compression rates. However, loss of image quality is recognizable in some of images in all compression rates.