(C) Daily Kos This story was originally published by Daily Kos and is unaltered. . . . . . . . . . . Kos Diabetes Group: GMI vs A1c [1] ['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.'] Date: 2023-10-06 Most diabetics and pre-diabetics are familiar with the A1c blood test. Since the 1990s, physicians have used this test to evaluate average glucose levels over the previous three months. While reliable, the A1c test only gives you a partial understanding of the level of glucose management over the last three months. The biggest issue with the A1c method of evaluating diabetes management is that it measures glucose levels over a long period and then provides an average reading. A good A1c reading doesn't always mean excellent glucose management. The data from a CGM will give you the most accurate GMI score With CGMs becoming more common, doctors are beginning to look at a new metric by which to measure glucose control – the Glucose Management Indicator (GMI). The GMI shows what your A1C levels are likely to be based on the average Continuous Glucose Monitoring (CGM) data over the past 10 to 14 days (basically the length of time you wear the CGM). While both GMI and A1c methods measure your blood sugar levels, the figures can differ some. A recent study by the University of Washington Diabetes Care Center analyzed 641 people with diabetes and found that the differences between A1c test results and GMI results were mostly minor: 50% of patients had differences of 0.5% or less. For example, if the GMI was 6%, the A1c ranged from 5.5% to 6.5%. 11% of patients had differences of 0.1% or less. For example, if the GMI was 6%, the A1c was between 5.9% and 6.1%. 22% of patients had a difference of 1% or greater. For example, if the GMI was 6%, the A1c was below 5% or greater than 7%. Some doctors believe that the GMI gives them a better picture of your glucose management efforts. For example, a person could spend one month with low blood sugar levels and one month with high sugar levels. At the end of the two months, the A1c test would show satisfactory average levels. Meanwhile, the person's health could be at serious risk. CGM technology with its ability to gather far more data than is ever available through fingersticks and A1c tests can help some people with diabetes gain more insight into their glucose fluctuations — and help them manage their diabetes better, allowing them get a more complete picture of the trends in their diabetes management. CGMs use a tiny sensor inserted under the top layer of skin to measure the level of glucose in your interstitial fluid and then transmits those readings every 1 to 5 minutes to a smartphone app or separate handheld device to allow you to see your glucose patterns in real-time. That information can help you make adjustments throughout the day to keep your blood sugar levels within your target range. You can see immediately when you experience a big jump or drop in blood sugar, and you can determine what led to those big spikes and dips. Did you eat something that sent your blood sugar levels soaring? Or did you exercise hard and send your blood sugar levels plummeting? The GMI is based on the average glucose value from the data collected by the CGM. How to calculate GMI To calculate GMI, you need to take the mean (average) glucose reading over the past 10 to 14 days and convert it from mg/dL to a percentage: GMI (Percentage) = 3.31 + 0.02392 x (glucose reading in mg/dL) Even if you don’t use a CGM, if you test regularly (3-4 times a day) using a standard glucometer and fingerstick, your meter should be able to show you the average of all your readings in the last 7 days, 14 days, and 30 days. Use the 14 day average in the formula above to calculate a rough estimate of your GMI. You should probably have at least 21 readings in the 14 day average used to calculate the GMI but more is obviously better. It will not be as accurate as a GMI calculated with data from a CGM, but it will give you a rough idea of what your A1c will be. You can use the info from a regular glucometer to calculate your GMI. Make sure you have 21 or more readings in the 14 day period your looking at. It won’t be as accurate as a score derived from data on a CGM but it will give you a rough idea of what your A1c is Overall, the GMI calculated with information obtained from a CGM gives a much more accurate indication of your overall glucose control than an AIc test, but until all patients are able to use a CGM doctors will probably stick with the A1c. [END] --- [1] Url: https://www.dailykos.com/stories/2023/10/6/2196585/-Kos-Diabetes-Group-GMI-vs-A1c?pm_campaign=front_page&pm_source=latest_community&pm_medium=web Published and (C) by Daily Kos Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified. via Magical.Fish Gopher News Feeds: gopher://magical.fish/1/feeds/news/dailykos/