Is there an HbA1c Threshold for Symptoms of Chronic Hyperglycemia?

Abstract

The minimum therapeutic goal regarding metabolic control for people with diabetes mellitus is the "absence of symptoms of hyperglycemia." However, it is uncertain whether a level of HbA1c can be defined that guarantees the absence of these symptoms. The aim was to define an HbA1c threshold above which most patients show hyperglycemic symptoms. In a multicenter cross-sectional study, 137 patients with type 1 and 285 with type 2 diabetes were asked about their symptoms during periods of hyperglycemia with a standardized questionnaire. Seventeen symptoms of hyperglycemia were summarized to the total hyperglycemia symptom score (THSS; min. 0; max. 68). The answers could be given according to the frequency and intensity in the last 4 - 6 weeks. The HbA1c threshold above which most patients showed hyperglycemic symptoms was 10.05% for patients with diabetes type 1 and 8.9%. for patients with type 2. Most confidence was reached on the symptoms of frequent urination" and "tiredness." The mean THSS was 19.4 (±9.0) and showed a positive correlation with age (r=0.167; p<0.001) and HbA1c (r=0.254; p<0.001). We identified an HbA1c threshold above which most patients show symptoms of hyperglycemia. In the treatment of people with diabetes mellitus, a safety margin to this threshold should be maintained to preserve well-being and avoid distress. However, since hyperglycemia symptoms are subject to many influencing factors, an adjustment of the therapy-both intensification and de-intensification-should always be carried out in combination with the requested hyperglycemia symptoms and HbA1c value.