Glenview Diabetes Doctor Credited For FDA Label Change

GLENVIEW, IL — Dr. Emily Szmuilowicz has been meeting with a diabetes patient, Wendy Seibel, 72, of Rosemont, for many years at the Northwestern Medicine Glenview Outpatient Center. A routine appointment, though, led to an important medical breakthrough.

During the visit, Seibel told Szmuilowicz, a graduate of Glenbrook South High School, that every time she took her hydroxyurea, a medication used to treat certain blood disorders, the readings on her continuous glucose monitor would spike dramatically. The glucose readings would stay that way for about six hours and then it would eventually come down, according to Szmuilowicz. Though Seibel's CGM readings would be high, if she did a traditional finger stick glucose measurement, it was much lower, leading to inconsistent numbers.

Seibel told her doctor that she would try to switch up the times she took her medication to see if that made a difference, but still the readings said there was a spike in her sugar levels. She even called Dexcom, the maker of her CGM, to let them know what she was seeing, but hydroxyurea wasn’t on the list of medications that could potentially spike her sugar levels.

As this had not been previously reported, Szmuilowicz decided to do some testing to confirm what her patient had observed. She had Seibel fast, then take her medication, and then compare the CGM reading to her finger stick glucose level every hour. Each time, according to Seibel, the CGM showed a spike, even when she had nothing to eat. Even taking the test at different times of the day and after varied meals, the spike in the CGM glucose level continued while the finger stick level didn't change dramatically at all. This led Szmuilowicz to hypothesize that hydroxyurea was likely interfering with the CGM readings.

Szmuilowicz discussed it with her colleague, Dr. Grazia Aleppo, and they reached out to the CGM manufacturer about their findings. The company performed testing on their own, and were able to confirm that hydroxyurea was interfering with Seibel's glucose levels. This all led to an official FDA label change. Seibel also wore two different glucose monitors simultaneously for two weeks, which showed divergent results and confirmed the interference, and these findings were recently published in the Diabetes Care, a monthly peer-reviewed medical journal.

"It makes me really proud to see how a novel discovery and contribution has come out of our very own Glenview diabetes program," Szmuilowicz said. "And that at the heart of the discovery, was just listening to the patient. I think it says a lot about how we approach our patient care."

The Northwestern Medicine Glenview Outpatient Center opened in March 2013 with just a handful of physicians and staff. Today, the center at 2701 Patriot Blvd. employs more than 100 employees, and more than 70 physicians. It has over 25 specialties, as well as internal medicine and pediatrics. In May 2018, the Cancer & Infusion Center opened. There is also a full diagnostic imaging suite and an Immediate Care Center open 7 days a week, 365 days a year. The center has an average of 900 patient appointments per day, each week.

"This really showcases the academic-community partnership that exists here," said Micah Eimer, MD, cardiologist and medical director at the Glenview Outpatient Center. "This also serves as a good reminder to always listen to the patient, no matter what the circumstances present. I’m incredibly proud that my colleague worked to make sure there was additional testing on this issue, and saw it through until there was an official FDA label change."

While Seibel is quick to give credit for the medical breakthrough to Szmuilowicz, officials at the Northwestern Medicine Glenview Outpatient Center also applaud their patient for being proactive with her treatment.

They said Seibel's daughter, who also has Type 1 diabetes, recently forwarded her an e-mail she received from the maker of her CGM, informing her that hydroxyurea is a medication that can spike glucose levels. The daughter knew she received this warning because of her mom, "who was determined to make a difference."