Medical staff X-ray a COVID-19 patient's lungs in the ICU...

Medical staff X-ray a COVID-19 patient's lungs in the ICU at Mount Sinai South Nassau hospital in Oceanside on April 14. Credit: Jeffrey Basinger

People stricken with COVID-19 who have diabetes, even some with no known diabetes, are coming into the hospitals with dangerously high blood sugar levels that require large doses of insulin, doctors say.

People with diabetes represent 30% to 40% of both hospitalized patients in general and patients hospitalized with COVID-19, doctors say. While diabetics routinely monitor themselves for spikes in their blood sugar and nondiabetics may experience high levels under stress or illness, doctors say COVID-19 poses special risks.

“There is more of a rise in blood sugar from COVID compared to other serious illnesses, in diabetics and in other patients, including those who might have had a trend toward prediabetes,” said Dr. Stuart Weinerman, associate chief, division of endocrinology at North Shore Long Island Jewish, a division of the Northwell Health System.

“Many COVID patients who would not need insulin before, will need it now,” he said. “And many who take insulin at home will need much higher doses because of the stress of the disease and the use of steroids. This is all so new we don’t have the published data to demonstrate the exact mechanism for why this is so.”

Studies show that diabetics face higher rates of intensive care and mortality. People with both type 1 and the far more common type 2 diabetes often suffer from other conditions like hypertension, cardiovascular disease and obesity that puts them even further at risk.

A study to be published in the Journal of Diabetes, Science and Technology — based on the medical records of over a thousand hospitalized COVID-19 patients — found that diabetics, and nondiabetics with high blood glucose, had a 28.8% mortality rate versus all other patients’ 6.2% mortality rate, said its senior author, Dr. David Klonoff, medical director of the Diabetes Research Institute at Mills-Peninsula Medical Center in San Mateo, California.

“If people come in with high glucose levels they are probably going to have a bad outcome,” Klonoff said.

Dr. Joshua Miller, medical director of diabetes care for Stony Brook Medicine, said that diabetes behaves differently with patients with COVID. “What we’re finding is that traditional treatments are less effective so patients are needing higher amounts of insulin to get blood sugars down to the normal range than we otherwise would. Other hospitals are finding that as well,” he said. “We are collaborating with hospitals in the tristate to try different approaches and share results.”

Stony Brook University Hospital is using different types of insulin not previously used in the hospital and at higher concentrations and more frequent doses, he said. However, he added, “What we are finding specifically with COVID is that no two COVID patients respond in exactly the same way, not just with diabetics on insulin but on all fronts.”

The virus causing COVID-19, originally thought to be a respiratory illness affecting the lungs, has turned out to mount a far more pervasive assault on various organs, including the heart, brain, intestines and kidneys. It has surprised the medical community, causing blood clots even in otherwise healthy young patients, strokes, cardiac arrest, seizures and brain swelling, renal failure requiring dialysis, and damage to the intestines and liver.

It isn’t known whether the high blood sugars are a side effect of the overall COVID disease process or result from a specific viral attack on the pancreas, the organ that produces the hormone insulin, said Dr. Shivani Agarwal, director of the Young Adult Diabetes Clinic at Montefiore and an assistant professor of medicine at Albert Einstein College of Medicine in the Bronx. Patients, even nondiabetics, are coming in with severe symptoms.

Autopsies performed on victims in prior epidemics of the SARS coronavirus, related but distinct from the coronavirus that causes COVID-19, “suggest the virus may infect the pancreas itself and cause insulin insufficiency,” said Agarwal.

She said that no published reports of post-mortems had evaluated the pancreas. “This is something we need to do,” she said.

Patients, even people never before diagnosed with diabetes, are coming in with severe symptoms, she said,

“This is anecdotal — we are seeing new cases of diabetes actually coming with what we call ketoacidosis from an insulin deficiency,” she said, referring to a potentially fatal buildup of blood acids called ketones. “It’s quite scary and quite surprising.”

“I pay attention to it because it’s so unique,” she said.

While the percentage of nondiabetic patients with COVID-19 who need insulin because of high blood sugar levels is under 5% at her hospital, the possible impact could be large, she said, noting that in a worldwide pandemic, “the implications have much farther reaches.”

Blood sugar levels can be too high or low for various reasons, including stress, infection, diet or amount and timing of exercise. But COVID-19 is causing very high blood sugar levels resistant to insulin in both type 1 and type 2 diabetes and requires high doses of insulin to treat.

“We are seeing patients with very reasonably controlled type 2 diabetes on oral medications and we’re seeing high blood sugars in those patients,” said Agarwal. “They’ve never been hospitalized for diabetes before.”

Insulin directs muscle and fat cells to take in glucose, or blood sugar, to use as fuel or store as fat. Type 1 diabetics don’t make insulin and need to inject insulin to survive. Ninety-two to 95% of diabetics have type 2, and make insufficient insulin. 

Stony Brook University Hospital is conducting a limited trial of continuous glucose monitoring, using a device approved by the FDA for use in outside hospitals. If proven reliable for hospitalized COVID patients, nurses who now must take frequent blood draws to measure blood glucose levels could lessen their exposure and PPE use, Miller said.

“We’re working on ways to validate the data so it’s reliable and actionable,” he said, noting that critical illness, including use of a ventilator, has “as yet unknown impacts on the blood test.”

The devices are already in use for patients who can self-monitor. Now Agarwal said that for patients at her hospital who cannot respond to alarms, receivers are placed outside the room or near nursing desks to notify nurses when an alarm goes off. Routine blood tests are conducted every four hours along with all the other nursing duties so as to minimize times each nurse has to don protective equipment and risk exposure to an infectious patient.

While data on COVID indicates older people, and people with underlying illness, tend to do worse, the disease still holds many mysteries for any particular person’s fate, doctors say.

 “As time goes by we’re going to learn a lot more which existing conditions, which clinical variables, which demographics determine someone’s risk for getting and surviving COVID,” said Miller, but for now, “COVID is the big unknown to every physician and every person in health care.”

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