Field Notes
The ICU and Blood Sugar Control Risks
Efforts by hospital ICU teams to reduce glucose readings of patients with diabetes might do more harm than good, according to an analysis published in Diabetes Care.
Michael Schwartz, MD, lead author and a UW Medicine endocrinologist, says he decided to study the phenomenon after talking with Irl Hirsch, MD, a colleague who had witnessed problems emerge among his ICU patients.
Schwartz and coauthors found that, among patients with diabetes, efforts to reduce blood glucose levels to what’s considered normal in a person without diabetes actually may harm the patients by triggering a dangerous reaction.
The article notes that relative hypoglycemia—or a decrease in glucose greater than or equal to 30% below prehospital admission levels—“has emerged as a major clinical concern because the standard glycemic target recommended for patients in the intensive care unit is associated with an increased mortality risk among some of the critically ill patients with diabetes.”
Low blood glucose, or hypoglycemia, can be dangerous because the brain depends on a steady supply of glucose to function. When someone's blood glucose levels fall below a level of approximately 40 mg/dL to 60 mg/dL, the sympathetic nervous system triggers the release of hormones and other chemical signals to drive blood glucose back up. This phenomenon is known as a counterregulatory response.
While this response can help return the blood glucose level to normal, in parallel, it also increases the heart rate and blood pressure, and perhaps activates the immune system. Schwartz and others in this review suspect this counterregulatory response may be the cause of higher death rates among ICU patients with diabetes who are treated for a high glucose level.
Patients with diabetes generally have a higher blood sugar level (100 to 200 mg/dL) than patients without diabetes, the study says. For a patient without diabetes, normal levels are 70 to 100 mg/dL
“The target range that’s established in the ICUs doesn’t differentiate between a patient with diabetes and a patient without diabetes,” Schwartz says. To establish the best blood sugar range, he says, a randomized clinical trial would need to determine the ideal glycemic level for ICU patients with, and without, diabetes.
People with diabetes usually have higher than normal blood sugar levels. Over time their bodies get used to these high blood sugar levels. As a consequence, when their blood sugar levels are brought into the normal range with treatment, their bodies incorrectly perceive the levels to be dangerously low, thereby triggering the counterregulatory response. Schwartz and his colleagues are studying how the body monitors and regulates blood sugar levels to understand how this response might be prevented or corrected.
While the brain clearly can sense when blood sugar is too low, exactly how this occurs isn’t well understood. For many years, it was thought that cells responsible for monitoring and regulating blood glucose levels resided in the brain. But work by UW Medicine researchers now indicates that blood glucose sensing neurons reside outside of the brain, located in places such as the liver and along blood vessels. These sensors monitor glucose concentrations in the blood and other tissues and send signals to brain centers that then respond to changes in levels, the study says.
“We anticipate that future strategies aimed at reversing the underlying defect can ameliorate or even eliminate the problem of relative hypoglycemia in patients with diabetes,” the authors conclude, “To achieve this goal will require an improved understanding of how brain glucose sensing works in normal individuals and how it becomes impaired with patients with diabetes.”
— Source: University of Washington School of Medicine and UW Medicine
Lonely College Students at Higher Risk of Unhealthy Diets and Physical Inactivity
Transitioning to a new environment, as many college first years do, can increase feelings of loneliness, and feelings of loneliness in college students have dramatically increased in the last decade, according to the National College Health Assessment. In addition, a 2021 survey reported that 44% of US college students described their weight as more than normal, ie, either in the overweight or obese category. Though loneliness has been linked to unhealthy weight and physical inactivity, there’s a lack of research on dietary behaviors in college students and the role loneliness can play in obesity in college students.
With data from the Mason: Health Starts Here cohort study, George Mason University alum Li Jiang, MS, found that loneliness was related to altered diet quality and physical inactivity. The research was done as part of Jiang's master's thesis, and Mason Nutrition and Food Studies Department Chair Lawrence J. Cheskin, MD; Associate Professor Lilian de Jonge, PhD; former faculty member Cara Frankenfeld, PhD; and former postdoctoral fellow Ziaul H. Rana, PhD, also contributed to the project.
"Our study supports a potential need for further research in understanding unhealthful dietary behavior and physical activity, which may be related to loneliness, an emotion that impacts many college students," Jiang says.
Sedentary (19.2%) and low active (53.8%) behaviors were more frequent in students reporting high loneliness (score ranges of four to six and seven to nine) than those reporting low loneliness (score of 10 to 12). Students reporting more loneliness had higher fat diets than students reporting less loneliness.
"Interventions to reduce loneliness may have a positive effect on health promotion in this population. This data goes along with other initial findings from the Health Starts Here study that college students are not meeting healthy dietary guidelines or getting enough physical activity," Cheskin says.
The study is a cross-sectional study that analyzed baseline data collected in the first wave of Mason: Health Start Here in 2019 and was funded by George Mason University's Institute for BioHealth Innovation.
"Loneliness Is Associated With Unhealthful Dietary Behaviors and Physical Inactivity Among US College Students" was published in November 2022 in the Journal of American College Health.
Mason: Health Starts Here is a first-of-its-kind transdisciplinary student cohort study to understand and improve the health and well-being of university students. This research will follow a broad sample of young adults, specifically Mason students, over time to capture the diversity of their experiences in college and how it affects their health and well-being.
— Source: George Mason University