Recent Northwestern Medicine study used app to track symptoms, recovery of long COVID patients

It has been nearly six years since the start of the COVID-19 pandemic, and one of the many questions doctors are still working to answer concerns the long-term effects.

Long COVID affects millions of people in the U.S. Doctors at Northwestern Medicine have been working to study long COVID for years through the Neuro COVID-19 Clinic. Recently, the clinic conducted a study where patients used an app to track how they were feeling and any progress.

The Neuro COVID-19 Clinic at Northwestern recently conducted a study where patients used an app to track their symptoms.

A household survey found that at least 6% or 18 million people in the U.S. had experienced long COVID or a post-COVID condition, but data has not been updated since 2024. 

University of Illinois Chicago epidemiologist Dr. Katrine Wallace said last March that experts estimate between 3% and 30% of people who have had COVID-19 experience long COVID. 

"Long COVID is defined as symptoms lasting more than three months after COVID-19 and neurologic manifestations include brain fog, headache, dizziness, alteration of smell and taste, insomnia, as well as intense fatigue," said Dr. Igor Koralnik, chief of neuroinfectious diseases and global neurology at Northwestern Medicine, who oversees the clinic, "and that really affects people's quality of life and ability to work."

So far, the Neuro COVID-19 Clinic has seen 3,300 patients since the beginning of the pandemic, Koralnik said. Some patients have had symptoms that have now lasted several years, and Koralnik said the study involving the app was intended to shed some light on what's going on for those patients.

"So we constructed an app, a mobile phone app that would allow patients to log in their daily symptoms from home. So. 'Brain fog? Yes/No. Fatigue? Yes/No,' and so on, and also their subjective impression of percent recovery compared to before COVID. So today, they may feel 50% recovered, the next day 40%, then later 60%," said Koralnik, "and our information technology department integrated this app into the MyChart platform that patients use to interface with their medical record, so the beauty of this is that they can be at home logging their daily symptoms, and we can see it through their medical record on the back end."

The study involved 63 patients who wanted to use the app for three months.

"We found two distinct populations of patients — those who improved, 43% of those, and those who did not improve during this time period, 57%," Koralnik said. "And what was different between the two populations? Well, first we saw that those who improved had more ups and downs on their road to recovery, with frequent setbacks, but also improvement, than those who did not improve — which tells us that it is not a linear road to recovery, but rather a very bumpy road."

Koralnik added that those whose conditions improved had better results on tests of cognition after three months, which indicates that it is important to help patients with that aspect of long COVID.

The study also found that women were less likely than men to improve, and those who had alteration to their sense of smell and taste were also less likely to improve.

So why are women less likely to improve? Unfortunately, we think that long COVID is a new autoimmune disease that's been triggered by the virus that now confuses the immune system that something abnormal is occurring in the body that needs to be attacked," Koralnik said, "and women are also more likely than to develop other autoimmune diseases like multiple sclerosis, rheumatoid arthritis, and lupus, for example."

The clinic is now launching another study about a link between sleep disorders and long COVID.

"So about 30, 40% of people who are coming to the clinic have an alteration of sleep, and some have insomnia. And we're doing another study that we're now actually writing up, looking for other causes of insomnia like obstructive sleep apnea in these people who maybe predated COVID, but had been uncovered by long COVID, and can be treated differently," Koralnik said.

Meanwhile, most of the patients involved in the study with the app said they found the technology "useful and satisfactory" — which has raised the idea of using similar apps for other chronic diseases to help empower patients as they recover, Koralnik said.

"This is the first time that such a symptom tracker app ash been used at Northwestern," he said.