More evidence for going beyond A1C: Time in range more accurately predicts complication risk than A1C.
For years people with diabetes have been leaving A1C behind as their primary indicator of blood sugar management. With the increase in Continuous Glucose Monitoring (CGM) technology availability and accuracy, time in range (percentage of time spent with blood sugars between 70 and 180) has become a more accurate indicator of glycemic stability, management efficacy and long term risk for complications. However, the FDA has still required the use of A1C as the standard to demonstrate effective management of diabetes for drug and technology developers when seeking FDA approval.
However there are many weaknesses with HbA1C. A1C is greatly impaired by disease states, metabolic changes and medications that alter the rate at which we produce and turn over red blood cells. A1C scores are also more impacted by the most recent 30 days than the previous two months. Finally a person may have an A1C of 6 because they are continually either very high or very low. This is certainly not healthy effective blood sugar management.
Data collected from the Diabetes Control and Complications Trial demonstrated that there is a clear correlation between retinopathy as well as microalbuminuria. Rates of retinopathy increased 64% for every 10% decrease of time in range. Microalbuminuria rates increased 40% for every 10% reduction of time in range among the 1440 participants. These findings lead researchers to recommend that time in range serve as a determinant for effective treatment.
This is encouraging as we also anticipate the coming year bringing the clinical world a new metric for measuring “Successful” diabetes management. Rather than a single A1C goal, this metric would quantify a combination of time in range, A1C, emotional health, blood pressure, and other complication risk factors. It is important that the entity that is providing oversight and determining what therapies are considered effective for treatment, be using a metric that actually measures wellness, not a single potentially misleading number.