Low Blood Sugar in Hospital Tied to Higher Death Risk for DiabeticsLast Updated: June 29, 2009. Hypoglycemia likely a sign of additional illness, suggest experts.
By Serena Gordon
MONDAY, June 29 (HealthDay News) -- Being a diabetic and having just one episode of low blood sugar during a hospital stay was associated with a significantly increased risk of dying, both in the hospital and up to a year later, new research shows.
In a study that included almost 2,600 people with diabetes who were hospitalized for a variety of ailments, researchers found that low blood sugar (hypoglycemia) occurred in nearly 8 percent of the patients, and that each additional day with a hypoglycemic episode was associated with an 85 percent increase in the risk of death while hospitalized. The study also found a 66 percent increased mortality risk for one year following discharge in patients who'd had hypoglycemia.
"We think hypoglycemia likely was a marker for severity of illness," explained study author Dr. Alexander Turchin, an assistant professor of medicine at Harvard Medical School and an associate physician at Brigham and Women's Hospital in Boston. "A patient gets admitted to the hospital, becomes more ill and stops eating. If they're using the same anti-diabetes regimen they do at home, they'll develop hypoglycemia."
Results of the study were published in the July issue of Diabetes Care.
Because high blood sugar levels are associated with numerous adverse health outcomes, researchers began investigating if lowering high blood sugar levels in critically ill patients would improve outcomes. An initial study found positive results for aggressively lowering blood sugar. However, since that time several studies have questioned this practice because they found an increased risk of mortality, possibly due to lowering blood sugar too much.
Most of the research was done in patients in intensive care, but the current study focuses on people hospitalized in the general wards for numerous different reasons -- from elective surgeries to infectious diseases.
Turchin and his colleagues analyzed data from 4,368 non-critical hospital admissions. Of these, 2,582 were people with diabetes -- both type 1 and type 2. About one-third of the people with diabetes received treatment with insulin.
Hypoglycemia was defined as a blood sugar reading of less than 50 milligrams per deciliter (mg/dl). The researchers found that 7.7 percent of the hospitalized people with diabetes had at least one episode of low blood sugar.
The researchers controlled the data for a number of factors, including the presence of other illnesses, and predicted what a normal length of stay for that condition should be.
"Even after including all of that, low blood sugar still gave us additional information about the prediction of mortality that we're not capturing with all the other metrics," said Turchin.
The risk of inpatient death jumped 85.3 percent for each additional day with hypoglycemia, the team found. Up to one year later, the risk of death was still increased by 65.8 percent for each additional day someone experienced hypoglycemia. The researchers also found that the length of a hospital stay increased by 2.5 days for each day there was at least one low blood sugar reading.
"If patients develop low blood sugar, they should be closely monitored for clinical deterioration," said Turchin. "Keeping blood sugar high doesn't have a benefit, but being too aggressive in lowering it may not be such as a good idea either."
Dr. Joel Zonszein, director of the clinical diabetes center at Montefiore Medical Center in New York City, said that his sense is that the higher risk of mortality in people with hypoglycemia is a result of underlying disease, rather than from aggressive treatment.
"There's no question that hypoglycemia is associated with a high mortality rate, but it's an association; there's no direct evidence of causality," he said.
Turchin said the researchers weren't able to do a comprehensive analysis to determine if a hypoglycemic episode that occurred for an obvious reason -- such as a late meal in someone who's been given insulin -- had the same increased risk that a spontaneously occurring low blood sugar episode did.
No matter what the cause, however, Turchin recommended that these patients be "more closely monitored to prevent low blood sugar, which can only exacerbate their problems."
To learn more about hypoglycemia, visit the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.
SOURCES: Alexander Turchin, M.D., assistant professor, medicine, Harvard Medical School, and associate physician, Brigham and Women's Hospital, Boston; Joel Zonszein, M.D., director, clinical diabetes center, Montefiore Medical Center, New York City; July 2009 Diabetes Care
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