Metformin: time to review its role and safety in chronic kidney disease.

■Metformin is recommended as first-line therapy for type 2 diabetes because of its safety, low cost and potential cardiovascular benefits. ■The use of metformin was previously restricted in people with chronic kidney disease (CKD) - a condition that commonly coexists with diabetes - due to concerns over drug accumulation and metformin-associated lactic acidosis. ■There are limited data from observational studies and small randomised controlled trials to suggest that metformin, independent of its antihyperglycaemic effects, may be associated with lower risk of myocardial infarction, stroke and all-cause mortality in people with type 2 diabetes and CKD. ■Research into the risk of metformin-associated lactic acidosis in CKD has previously been limited and conflicting, resulting in significant variation across international guidelines on the safe prescribing and dosing of metformin at different stages of renal impairment. ■Present-day large scale cohort studies now provide supporting evidence for the safe use of metformin in mild to moderate renal impairment (estimated glomerular filtration rate [eGFR] 30-60 mL/min/1.73m2 ). However, prescribing metformin in people with severe renal impairment (eGFR < 30 mL/min/1.73m2 ) remains a controversial issue. Due to observed increased risk of lactic acidosis and all-cause mortality in people with type 2 diabetes and severe renal impairment, it is generally recommended that metformin is discontinued if renal function falls below this level or during acute renal deterioration.

Is Thermal Imaging a Useful Predictor of the Healing Status of Diabetes-Related Foot Ulcers? A Pilot Study.

INTRODUCTION: In clinical practice, both area and temperature of the ulcer have been shown to be effective in tracking the healing status of diabetes-related foot ulcer (DRFU). However, traditionally, the area of the DRFU is measured regardless of the temperature distribution. The current prospective, observational study used thermal imaging, as a more accurate tool, to measure both the area and the temperature of DRFU. We aimed to predict healing of DRFU using thermal imaging within the first 4 weeks of ulceration. METHOD: A pilot study was conducted where thermal and color images of 26 neuropathic DRFUs (11 healing vs 15 nonhealing) from individuals with type 1 or 2 diabetes were taken at the initial clinic visit (baseline), at week 2, and at week 4. The thermal images were segmented into isothermal patches to identify the wound boundary and area corresponding to temperature distribution. Five parameters were obtained: temperature of the wound bed, area of the isothermal patch of the wound bed, area of isothermal patch of periwound, number of isolated isothermal patches of the wound region, and physical wound bed area from color image. The ulcers were also measured by experienced podiatrists over 4 consecutive weeks and used as the healing reference. RESULTS: For healing cases, the ratio of the area of the wound bed to its baseline measured using thermal images was found to be significantly lower at 2 weeks compared to nonhealing cases and this corresponded with a 50% reduction in area of DRFU at 4 weeks (group rank-based nonparametric analysis of variance P = .036). In comparison, neither the planimetric area measured using color images nor the temperature of the wound bed was associated with the healing. CONCLUSION: This study of 26 patients demonstrates that change in the isothermal area of DRFU can predict the healing status at week 4. Thermal imaging of DRFUs has the advantage of incorporating both area and temperature allowing for early prediction of the healing of these ulcers. Further studies with greater sample sizes are required to test the significance of these results.

High-Resolution Spectral Analysis Accurately Identifies the Bacterial Signature in Infected Chronic Foot Ulcers in People With Diabetes.

Diabetic foot infections are a major cause of hospitalization, and delayed treatment can lead to numerous complications. The aim of this research was to investigate high-resolution spectroscopy of the wound center and periwound area for real-time estimation of multispectral signature of bacteria at the base of diabetic foot ulcers. We investigated the spectrum of the reflected visual light from diabetic foot ulcers and developed a method that identifies the presence of bacteria in the wound infections. We undertook a prospective pilot study on 18 patients with type 1 and type 2 diabetes and chronic diabetic foot ulcers. The spectral coefficients were directly compared with the results from the wound swab. The results of the multispectral analysis demonstrated 100% sensitivity, with 100% negative predictive values of identifying the presence of the bacteria, which was the cause of the infection in the wound. The results of our study suggest that the changes in the multispectral properties of the wound can be used to identify the presence of bacteria in the infected area using a noninvasive device without any contact with the wound. This technique holds great promise for real-time objective evaluation of the wound infection status beyond the standard visual assessment of diabetic foot ulcers.