Acute caloric restriction improves glomerular filtration rate in patients with morbid obesity and type 2 diabetes.

AIM: The role of caloric restriction in the improvement of renal function following bariatric surgery is still unclear; with some evidence showing that calorie restriction can reduce proteinuria. However, data on the impact of caloric restriction on renal function are still lacking. METHODS: Renal function, as measured by glomerular filtration rate (GFR), was evaluated in 14 patients with type 2 diabetes mellitus, morbid obesity and stage 2 chronic kidney disease before and after a 7-day very low-calory diet (VLCD). RESULTS: After the VLCD, both GFR and overall glucose disposal (M value) significantly increased from 72.6 ± 3.8 mL/min/1.73 m(-2) BSA to 86.9 ± 6.1 mL/min/1.73 m(-2) BSA (P=0.026) and from 979 ± 107 µmol/min(1)/m(2) BSA to 1205 ± 94 µmol/min(1)/m(2) BSA (P=0.008), respectively. A significant correlation was observed between the increase in GFR and the rise in M value (r=0.625, P=0.017). CONCLUSION: Our observation of improved renal function following acute caloric restriction before weight loss became relevant suggesting that calory restriction per se is able to affect renal function.

Impact of glycemic variability on cardiovascular outcomes beyond glycated hemoglobin. Evidence and clinical perspectives.

AIMS: The aim of this review is to focus on intra-day glucose variability (GV), specifically reviewing its correlation with HbA1c, the methods currently available to measure it, and finally the relationship between GV and cardiovascular outcomes, in type 1 and type 2 diabetic patients, and in the non-diabetic population. DATA SYNTHESIS: The term GV has been used in the literature to express many different concepts; in the present review, we focus our attention on intra-day GV. In particular, we try to assess whether GV provides additional information on glycemic control beyond HbA1c, since GV seems to be incompletely expressed by HbA1c, particularly in patients with good metabolic control. Many different indexes have been proposed to measure GV, however at the moment no "gold standard" procedure is available. Evidence in vitro, in experimental settings and in animal studies, shows that fluctuating glucose levels display a more deleterious effect than constantly high glucose exposure. However, these findings are not completely reproducible in human settings. Moreover, the relationship between GV and cardiovascular events is still controversial. CONCLUSIONS: The term GV should be reserved to indicate intra-day variability and different indexes of GV should be used, depending on the metabolic profile of the population studied and the specific issue to be investigated. Self glucose monitoring or continuous glucose monitoring should be used for assessing glucose variability.