The association between long-term glycemic control and all-cause mortality is different among older versus younger patients with diabetes mellitus and maintenance hemodialysis treatment.

Aims: Knowledge about association between glycated hemoglobin (HbA1c) and risk of all-cause mortality in patients with diabetes mellitus on maintenance hemodialysis (HD)-treatment is sparse. The study aims to investigate association between HbA1c and all-cause mortality in patients with diabetes and maintenance HD-treatment, separately for two age groups- above and below 75 years.

Methods: 2487 patients (mean age 66 years, 66 % men) were separated in two age groups: ≤75 years (n = 1810) and > 75 years (n = 677) and followed up between 2008 and 2018. Hazard ratios (HR) and 95 % confidence intervals (CI) for associations between HbA1c and all-cause mortality were calculated using Cox-regression-models.

Results: 1295 (52 %) patients died and 473 (70 %) among the patients above 75 years old. In the multivariate analysis, HbA1c5-6 % was used as reference. In patients ≤ 75 years old, only increased HbA1c > 9.7 %, HR2.03(CI1.43-2.89) was associated with increased risk of all-cause mortality. In patients > 75 years, HbA1c ≤ 5 %, HR1.67(CI1.16-2.40); HbA1c6.9-7.8 %, HR1.41(CI1.03-1.93) and HbA1c8.7-9.7 %, HR1.79 (CI1.08-2.96) were associated with increased risk of all-cause mortality.

Conclusions: We found a J-shaped association between HbA1c and mortality only in diabetic HD-patients > 75 years. This probably indicates that in an old population of diabetic HD-patients, both intensive glucose control and hyperglycemia could be harmful and associated with higher risk of death.