The metabolic deterioration that antedates diabetes: personal trajectories of HbA_1c and fasting glucose as early indicators and possible triggers for intervention

Abstract

HbA(1c) testing has become an accepted means of diagnosing diabetes as an alternative to blood glucose levels. However, population-based norms of glucose and of HbA(1c) levels do not enable the detection of diabetes at an early enough stage to thwart complications. Personal trajectories of glucose levels show steep increases a number of years prior to diabetes diagnosis. Here, we hypothesize that a comparable time-dependent deviation in an individual's HbA(1c) level may be an early manifestation of disease that should prompt lifestyle modifications. We predict that analysis of personal trajectories of glucose and of HbA(1c) will promote earlier intervention and a greater reduction in disease complications than current standards, which are based on population-based norms.

Dysglycemia and long‐term mortality: observations from the Israel study of glucose intolerance, obesity and hypertension

“…The IEC defined a lower risk category for developing type 2 diabetes in those with a HbA 1c ≥ 5.7–5.9% (39–41 mmol/mol) and a higher risk category in those with HbA 1c ≥ 6.0–6.4% (42–46 mmol/mol). The use of HbA 1c for screening and diagnosing dyglycemic states has recently been reviewed and remains controversial .…”

HbA1c for diagnosis of type 2 diabetes. Is there an optimal cut point to assess high risk of diabetes complications, and how well does the 6.5% cutoff perform?

“…In brief, there are some obvious advantages of the HbA 1c : there is no need to fast, the HbA 1c does not reflect acute events like stress or vigorous physical exercise, the preanalytical stability is larger than in glucose measurements, and coefficients of variation are lower than for FPG and oral glucose tolerance test. An important drawback of the HbA 1c as a diagnostic criterion is its dependence on various nonglycemic factors 5. Factors which go together with a decreased turnover of red blood cells, like iron deficiency, renal failure, or vitamin B12 deficiency, lead to higher HbA 1c values, whereas factors which coincide with shorter life spans of red blood cells, like hemolytic anemia and chronic liver disease, lead to lower HbA 1c levels.…”

Social Determinants of Health and Preclinical Glycemic Control in Newly Diagnosed First-Episode Psychosis Patients

“…Instead, we relied on detecting variability in HbA1c levels as an indication of the state of glycemic control. 26 The percentage of HbA1c is a function of the amount of plasma glucose available to chemically react (spontaneously) with the circulating hemoglobin molecule during the previous 8 to 12 weeks, 27 acting as an indirect marker of insulin resistance. Clinically, HbA1c levels reflect the average state of glycemic regulation, hence its use for treatment monitoring in diabetes.…”