COVID-19 brought about a large rise in blood circulation disorder cases, study suggests

The number of patients diagnosed with a chronic and oftentimes debilitating blood circulation disorder has risen sharply in the wake of COVID-19, according to new research from the University of Toledo.

Scientists and physicians have long believed postural orthostatic tachycardia syndrome, commonly known as POTS, could be brought on by viral infections. The Epstein-Barr virus in particular has been posited as a possible trigger for the syndrome, which is characterized by an inability to regulate blood pressure and heart rate.

The UToledo study, however, points to the COVID-19 pandemic causing an unprecedented acceleration in what was once thought to be a relatively rare condition.

It also suggests, the researchers say, that many patients suffering from what clinicians have broadly called long COVID may actually have POTS.

“We’ve suspected for several years now that there is an association between COVID and POTS. I’m seeing this in my own clinic. My waiting list is longer than it has ever been,” said Dr. Blair Grubb, a UToledo Health cardiologist who has treated and studied POTS for more than three decades. “Now we have the data to back that up. This study helps give validity and voice to these patients, and it gives us a treatable target.”

Grubb and his colleagues examined data combed from the electronic medical records of more than 65 million U.S. patients, comparing the incidence and prevalence of POTS before and after the emergence of COVID-19.

The differences were stark.

From January 2018 to March 1, 2020—the date researchers used as the cutoff for the pre-COVID era—the study found an estimate of 4.21 new cases diagnosed per month. That rose to 22.66 new cases per month from March 2, 2020, to June 2024, representing a more than five-fold increase.

The study also found the incidence rate of POTS was 1.42 per 1 million person-years before COVID and 20.3 cases per 1 million person-years after COVID.

The research was recently published in the European Heart Journal – Quality of Care and Clinical Outcomes.

Though the mechanisms behind it are not fully understood, POTS is effectively a blood-pooling disorder. When someone stands up, gravity pulls the blood in their body downward. For most of us, our body compensates by tightening the blood vessels in the lower half of the body.

In POTS patients, however, that constriction of blood vessels doesn’t happen. Instead, blood drains downward and reduces the brain’s supply of oxygen. The heart beats harder and faster as it tries to ship more oxygen to the brain, but with limited blood supply coming in, it can’t catch up with demand.

The resulting symptoms can include dizziness, fatigue, fainting and a whole host of other symptoms including pain, anxiety and brain fog.

Dharmindra Dulal, a fourth-year medical student and the lead author of the study, said the paper adds clear scientific evidence to the strong relationship between COVID-19 infection and the development of POTS—a link that previously had been limited to anecdotal accounts.

But more importantly, UToledo’s research helps to add clarity to the experience of some individuals who have been left dealing with debilitating aftereffects of COVID infection.

“We talk about long COVID,” Dulal said. “That’s a big umbrella and there is a lot of disease underneath it. We can’t just say ‘this patient has long COVID.’ We need to diagnose each condition separately, and I think what’s most valuable about this paper is that we can confidently say POTS is one part of long COVID.”

Intriguingly, there appears to be a parallel in the recent spike in POTS from our not-so-distant history. Following the 1918 influenza pandemic, one prominent physician wrote about a confounding group of cardiovascular symptoms in British soldiers who had served in World War I.

“They had POTS,” Grubb said. “He didn’t call it that, but he’s describing it absolutely perfectly. This is not new. I think viral infections have triggered these events throughout time, it’s just that we put it all together recently. We have a good idea of what’s going on now, whereas in the past they didn’t. And we’re seeing that COVID is really good at causing POTS.”

While UToledo researchers say the syndrome still lacks broad recognition even today, awareness has been growing.

“I think people are starting to recognize POTS more as a disease entity itself, and papers like this only help to raise awareness,” said Dr. Ahmed Maraey, a cardiology fellow in the College of Medicine and Life Sciences and the study’s corresponding author.

That awareness, Maraey said, brings with it hope for more effective ways of treating POTS in the future.

“If we know there is a disease here, we can do more for it. We can do more clinical trials, we can look for new treatments, we can train more people to be able to manage the disease,” he said. “Once we’ve identified there is a problem, we can better deal with it.”

The number of patients diagnosed with a chronic and oftentimes debilitating blood circulation disorder has risen sharply in the wake of COVID-19, according to new research from the University of Toledo.

Scientists and physicians have long believed postural orthostatic tachycardia syndrome, commonly known as POTS, could be brought on by viral infections. The Epstein-Barr virus in particular has been posited as a possible trigger for the syndrome, which is characterized by an inability to regulate blood pressure and heart rate.

The UToledo study, however, points to the COVID-19 pandemic causing an unprecedented acceleration in what was once thought to be a relatively rare condition.

It also suggests, the researchers say, that many patients suffering from what clinicians have broadly called long COVID may actually have POTS.

“We’ve suspected for several years now that there is an association between COVID and POTS. I’m seeing this in my own clinic. My waiting list is longer than it has ever been,” said Dr. Blair Grubb, a UToledo Health cardiologist who has treated and studied POTS for more than three decades. “Now we have the data to back that up. This study helps give validity and voice to these patients, and it gives us a treatable target.”

Grubb and his colleagues examined data combed from the electronic medical records of more than 65 million U.S. patients, comparing the incidence and prevalence of POTS before and after the emergence of COVID-19.

The differences were stark.

From January 2018 to March 1, 2020—the date researchers used as the cutoff for the pre-COVID era—the study found an estimate of 4.21 new cases diagnosed per month. That rose to 22.66 new cases per month from March 2, 2020, to June 2024, representing a more than five-fold increase.

The study also found the incidence rate of POTS was 1.42 per 1 million person-years before COVID and 20.3 cases per 1 million person-years after COVID.

The research was recently published in the European Heart Journal – Quality of Care and Clinical Outcomes.

Though the mechanisms behind it are not fully understood, POTS is effectively a blood-pooling disorder. When someone stands up, gravity pulls the blood in their body downward. For most of us, our body compensates by tightening the blood vessels in the lower half of the body.

In POTS patients, however, that constriction of blood vessels doesn’t happen. Instead, blood drains downward and reduces the brain’s supply of oxygen. The heart beats harder and faster as it tries to ship more oxygen to the brain, but with limited blood supply coming in, it can’t catch up with demand.

The resulting symptoms can include dizziness, fatigue, fainting and a whole host of other symptoms including pain, anxiety and brain fog.

Dharmindra Dulal, a fourth-year medical student and the lead author of the study, said the paper adds clear scientific evidence to the strong relationship between COVID-19 infection and the development of POTS—a link that previously had been limited to anecdotal accounts.

But more importantly, UToledo’s research helps to add clarity to the experience of some individuals who have been left dealing with debilitating aftereffects of COVID infection.

“We talk about long COVID,” Dulal said. “That’s a big umbrella and there is a lot of disease underneath it. We can’t just say ‘this patient has long COVID.’ We need to diagnose each condition separately, and I think what’s most valuable about this paper is that we can confidently say POTS is one part of long COVID.”

Intriguingly, there appears to be a parallel in the recent spike in POTS from our not-so-distant history. Following the 1918 influenza pandemic, one prominent physician wrote about a confounding group of cardiovascular symptoms in British soldiers who had served in World War I.

“They had POTS,” Grubb said. “He didn’t call it that, but he’s describing it absolutely perfectly. This is not new. I think viral infections have triggered these events throughout time, it’s just that we put it all together recently. We have a good idea of what’s going on now, whereas in the past they didn’t. And we’re seeing that COVID is really good at causing POTS.”

While UToledo researchers say the syndrome still lacks broad recognition even today, awareness has been growing.

“I think people are starting to recognize POTS more as a disease entity itself, and papers like this only help to raise awareness,” said Dr. Ahmed Maraey, a cardiology fellow in the College of Medicine and Life Sciences and the study’s corresponding author.

That awareness, Maraey said, brings with it hope for more effective ways of treating POTS in the future.

“If we know there is a disease here, we can do more for it. We can do more clinical trials, we can look for new treatments, we can train more people to be able to manage the disease,” he said. “Once we’ve identified there is a problem, we can better deal with it.”