Glucose variability in maintenance hemodialysis patients with type 2 diabetes

To the Editor: We read with interest the article by Bomholt et al, “Glucose variability in maintenance hemodialysis patients with type 2 diabetes: Comparison of dialysis and non-dialysis days” published online in this journal. With the use of continuous glucose monitoring the study aimed to examine glucose variations induced by hemodialysis (HD) in patients with type 2 diabetes. Similar median sensor glucose values were found for days on and off HD and nocturnal glucose levels were modestly increased on dialysis days. The authors concluded that findings indicate that antidiabetic treatment does not need to be differentiated on dialysis versus nondialysis days in patients with type 2 diabetes undergoing maintenance HD. We congratulate the authors on their efforts in conducting a comprehensive assessment of HD-influenced glucose excursions and highlighting a very clinically relevant topic. We do not have any criticism of the study, but we would like to make a comment and propose a data sub-analysis. The authors suggested that the reduction in plasma insulin possibly explains the nocturnal increase in mean sensor glucose on dialysis days as insulin is removed from plasma in the HD filter by diffusion, convection, and absorption leading to relative hypoinsulinemia. A total of 27 patients were included in the study, 20 were treated with insulin only, 5 were treated with a combination of oral antidiabetics (OADs) and insulin, and 2 with OADs only. As the types of OADs were not stated and they may have varying impacts on glycemia in connection with HD we respectfully suggest providing a similar separate analysis as published with the data of those 20 insulin-only treated patients. We believe it might show a more prominent difference between days on and off HD. In addition, the type of insulin may matter in end-stage renal disease. For example, the pharmacokinetics of insulin detemir or degludec is not affected by renal impairment, whereas this is not true for insulin glargine or human insulin products. Also, an analysis of the correlation between the daily amount of insulin and glucose concentration changes might support the author’s explanation for the above-mentioned glycemia difference. We respectfully suggest taking these points into account, especially if a study continuation is planned.