Visit-to-Visit Hemoglobin A1c Variability Is Associated With the Risk of Lower-Extremity Amputation in Patients With Type 2 Diabetes

Trends and risk factors of diabetes and prediabetes in US adolescents, 1999-2020

AIMS

To assess the national trends in prevalence of diabetes and prediabetes and their major risk factors among adolescents in the US.

METHODS

We analyzed data on 6,936 adolescents aged 12 to 19 years from the National Health and Nutrition Examination Surveys (NHANES) between 1999 and 2020. Diabetes was defined by self-reported physician-diagnosis (diagnosed) and by fasting plasma glucose and HbA1c levels (undiagnosed). Prediabetes was identified by fasting plasma glucose and HbA1c levels. Logistic regression was performed to estimate the associations of major risk factors with diabetes and prediabetes.

RESULTS

The prevalence of prediabetes in adolescents increased from 11.5% in 1999-2002 to 36.3% in 2015-2020. The prevalence of diabetes increased from 0.82% (0.62% of diagnosed and 0.20% of undiagnosed) in 1999-2002 to 1.14% (0.76% of diagnosed and 0.38% of undiagnosed) in 2015-2020, but the increase was not statistically significant (P value = 0.69). Obesity was significantly associated with higher odds of diabetes and prediabetes while boys and Mexican Americans had a significantly higher risk of prediabetes than their counterparts.

CONCLUSIONS

The prevalence of prediabetes among adolescents in the US has more than tripled from 1999 to 2020. Obese adolescents are at the greatest risk for diabetes and prediabetes.

Trends in obesity prevalence and cardiometabolic risk factor control in US adults with diabetes, 1999-2020

OBJECTIVE

Trends in obesity prevalence and trends in control of cardiometabolic risk factors among National Health and Nutrition Examination Survey participants with diabetes from 1999 through 2020 were analyzed.

METHODS

Adults who were 20 years or older and who reported having received a diagnosis of diabetes from a physician were included.

RESULTS

The prevalence of overall obesity, obesity class II, and obesity class III increased from 46.9%, 14.1%, and 10.3% in 1999 to 2002 to 58.1%, 16.6%, and 14.8% in 2015 to 2020, respectively. The prevalence of participants who achieved glycemic control (HbA1c <7%) increased from 42.5% in 1999 to 2002 to 51.8% in 2007 to 2010, then decreased to 48.0% in 2015 to 2020. The prevalence of participants who achieved blood pressure control (<140/90 mmHg) or achieved non-high-density lipoprotein cholesterol control (<130 mg/dL) increased throughout the study periods. The prevalence of participants who met all three risk factor goals increased from 8.3% in 1999 to 2002 to 21.2% in 2011 to 2014 and then decreased to 18.5 in 2015 to 2020. Participants with obesity showed worsening glycemic control and lipid control than participants with normal weight.

CONCLUSIONS

There were increasing trends in prevalence of obesity, blood pressure control, and lipid control from 1999 to 2002 to 2015 to 2020. Participants with obesity showed worsening glycemic control and lipid control than normal-weight participants.

Glycaemic variabilities: Key questions in pursuit of clarity

After years of intensive investigation, the definition of glycaemic variability remains unclear and the term variability in glucose homoeostasis might be more appropriate covering both short and long-term glycaemic variability. For the latter, we remain in the search of an accurate definition and related targets. Recent work leads us to consider that the within-subject variability of HbA1c calculated from consecutive determinations of HbA1c at regular time-intervals could be the most relevant index for assessing the long-term variability with a threshold value of 5% (%CV = SD of HbA1c/mean HbA1c) to separate stability from lability of HbA1c. Presently, no one can deny that short- and long-term glucose variability should be maintained within their lower ranges to limit the incidence of hypoglycaemia. Usually, therapeutic strategies aimed at reducing post-meal glucose excursions, i.e. the major contributor to daily glucose fluctuations, exert a beneficial effect on the short-term glucose variability. This explains the effectiveness of adjunct therapies with either GLP- receptor agonists or SGLT inhibitors in type 2 diabetes. In type 1 diabetes, the application of a CGM device alone reduces the short-term glycaemic variability. In contrast, sophisticated insulin delivery does not necessarily lead to such reductions despite marked downward shifts of 24-hour glycaemic profiles. Such contrasting observations raise the question as to whether the prolonged wear of CGM devices is or not the major causative factor for improvement in glucose variability among intensively insulin-treated persons with type 1 diabetes.

Glucose variability and diabetes complications: Risk factor or biomarker? Can we disentangle the "Gordian Knot"?

« Variability in glucose homoeostasis » is a better description than « glycaemic variability » as it encompasses two categories of dysglycaemic disorders: i) the short-term daily glucose fluctuations and ii) long-term weekly, monthly or quarterly changes in either HbA1c, fasting or postprandial plasma glucose. Presently, the relationship between the "variability in glucose homoeostasis" and diabetes complications has never been fully clarified because studies are either observational or limited to retrospective analysis of trials not primarily designed to address this issue. Despite the absence of definitive evidence from randomized controlled trials (RCTs), it is most likely that acute and long-term glucose homoeostasis "cycling", akin to weight and blood pressure "cycling" in obese and hypertensive individuals, are additional risk factors for diabetes complications in the presence of sustained ambient hyperglycaemia. As hypoglycaemic events are strongly associated with short- and long-term glucose variability, two relevant messages can be formulated. Firstly, due consideration should be given to avoid within-day glucose fluctuations in excess of 36% (coefficient of variation) at least for minimizing the inconvenience and dangers associated with hypoglycaemia. Secondly, it seems appropriate to consider that variability in glucose homoeostasis is not only associated with cardiovascular events but is also a causative risk factor via hypoglycaemic episodes as intermediary step. Untangling the" Gordian Knot", to provide confirmation about the impact of variability in glucose homoeostasis and diabetes complications remains a daunting prospect.