Correlates of low hemoglobin A1c in maintenance hemodialysis patients

Abstract

PURPOSE: The optimal target for glycemic control has not been established for diabetic maintenance hemodialysis (MHD) patients. METHODS: A 6-year cohort (October 2001- December 2006) of 347 diabetic MHD patients with HbA1c data was examined for associations between HbA1c and mortality. Death hazard ratios (HR) were estimated using Cox regressions and cubic splines. RESULTS: In these 347 patients (age, 59 +/- 11 years; 49 % women; 28 % African Americans; and 55 % Hispanics), each 0.5 % decline in HbA1c below 6 % was associated with a 4.7 times higher death risk (HR = 4.7; 95 % CI 1.7-12.7) in the fully adjusted model. Factors associated with lower HbA1c levels (<6 % compared to 6-7 %) were: Hispanic ethnicity (OR = 2.9; 95 % CI 1.1-7.9), higher mid-arm muscle circumstance (OR = 1.1; 95 % CI 1.0-1.3), higher total iron-binding capacity (OR = 1.03; 95 % CI 1.01-1.05), and higher iron saturation ratio (OR = 1.14; 95 % CI 1.03-1.26). HbA1c levels >7 % showed a consistent trend toward elevated mortality risk (HR = 1.18; 95 % CI 0.99-1.41) after multivariate adjustment. CONCLUSIONS: In diabetic MHD patients with burnt-out diabetes, characterized by HbA1c <6 %, even lower HbA1c levels are associated with significantly higher death risk. Additional studies are needed to determine the optimal target for HbA1c levels in different subgroups of diabetic MHD patients.