Research news tip sheet: Story ideas from Johns Hopkins Medicine

JOHNS HOPKINS MEDICINE HELPS FIND CAUSE OF GUILLAIN-BARRE SYNDROME OUTBREAK IN PERU

Media Contact:
Michel Morris,
melben1@jhmi.edu

In the spring of 2019, Peruvian neurologists saw a significant increase in the number of patients with Guillain-Barre syndrome (GBS). This rare disorder occurs when a person's immune system damages the nerves, causing muscle weakness and sometimes paralysis. Although GBS typically only affects 3,000 - 6,000 people annually in the United States (or about 1 in 100,000), Peruvian doctors documented hundreds of cases between May and July 2019 and deemed it an outbreak.

A multinational team of GBS experts collaborated with Peruvian neurologists led by Ana Ramos from the Hospital Cayetano Heredia in Lima to clarify the causes of the outbreak and identify the culprit. Among the members of the international team was Carlos Pardo, M.D., a neurology professor at the Johns Hopkins University School of Medicine.

Pardo and other Johns Hopkins Medicine neurologists, microbiologists and computational biologists helped Peruvian neurologists identify the cause to be a common diarrheal infection by bacteria called Campylobacter jejuni. The team's findings are reported in the March 2021 issue of the journal Neurology, Neuroimmunology and Neuroinflammation.

While a third of GBS patients recover completely, another third may be permanently left with significant muscle impairment or mobility problems.

"It is a major problem for Peru's public health system," says Pardo. "Just having even 10 to 20 patients can overwhelm a system. They were seeing hundreds of cases in just over a few months."

The multinational team identified the cause of the outbreak by investigating blood, feces and spinal fluid samples from patients with GBS. The group knew that a bacterial infection was likely to be the initial trigger, but needed to identify the specific type so that it could be appropriately controlled.

Pardo and his team used genetic and molecular tools to identify the strain of bacteria in the samples. They found that it was not a new bacterium, but one associated with other GBS outbreaks in South America and China called Campylobacter jejuni. While trying to fight the bacteria, a patient's immune system can mistakenly attack the nervous system as well, resulting in GBS.

Once the researchers pinpointed the responsible bacterial strain, they were able to suggest potential treatments, such as vaccines and antibiotics, best suited for C. jejuni. Public health officials also were able to target measures to stop the bacteria from contaminating Peru's food and water supplies.

Pardo is available for interviews.

HEART DISEASE GAINING ON CANCER AS A MAJOR CAUSE OF DEATH IN YOUNG WOMEN, SAY RESEARCHERS

Media Contact:
Brian H. Waters,
bwaters3@Jhmi.edu

It's no secret that women tend to put the health of others before their own, especially those who must care for children, manage a household, work full time and shoulder other responsibilities. So, it may not be surprising that a recent nationwide study by Johns Hopkins Medicine researchers revealed women younger than 65 are dying from heart disease at an increased rate compared with past years.

"Young women in the United States are becoming less healthy, which is now reversing prior improvements seen in heart disease deaths for the gender," says Erin Michos M.D., M.H.S., director of women's cardiovascular health and associate professor of medicine at the Johns Hopkins University School of Medicine. "In a previous study in December 2018, we showed that more attention should be paid to the health of young women, particularly those with the risk factors that contribute to heart disease."

"Our latest research confirms that need still exists," she says.

In the new study -- an analysis of U.S. death certificates between 1999 and 2018 from a national database -- Michos and her colleagues compared heart disease and cancer deaths in women under 65. Their findings were reported Feb. 8, 2021, in the European Heart Journal - Quality of Care and Clinical Outcomes.

The researchers found that overall during the 10-year study period, cancer was the most prevalent cause of premature death in women under 65 -- slightly more than twice as much as heart disease. However, the overall cancer mortality rate (age adjusted) for women under 65 decreased from 62 to 45 deaths per 100,000 people while the overall heart disease mortality rate (age adjusted) dropped from 29 to 23 deaths per 100,000.

Another finding from the study was that the annual percentage change (APC) in age-adjusted mortality rates for cancer declined year after year during the study period, while it increased for heart disease in two specific groups from 2010 to 2018: women 25 to 34 (2.2%) and women 55 to 64 (0.5%). The APCs rose significantly after 2008 for women living in the midwestern United States, medium and small metropolitan areas, and rural areas. Additionally, APCs were found to have increased for white women from 2009 to 2013 and for Native American women from 2009 to 2018.

Finally, the researchers determined the mortality gap between cancer and heart disease in women under 65 narrowed from a mortality rate (age adjusted) of 33 deaths per 100,000 in 1999 to 23 deaths per 100,000 in 2018.

Compounding the problem of premature death from heart disease in women under 65, say the researchers, is the commonly held misconception that women are not at risk for heart disease before menopause. But in fact, statistics show one-third of all heart issues in women occur before age 65.

Another major factor -- the gender gap in cardiac disease care -- was revealed in the 2018 study by Michos and her colleagues.

"We showed that women were not getting the same level of care as men, and they feel that way too. Women are more likely to report communication problems with health care providers and dissatisfaction with their health care experience, and we think this contributes to the disparities that we see when it comes to getting preventive and other treatment for cardiovascular disease," said Michos after the 2018 study was published.

Along with advocating for equal health care, Michos recommends that women combat the risk of premature cardiac death by eating a healthy and balanced diet, getting regular physical activity, not smoking, and maintaining healthy blood pressure, blood sugar, cholesterol level and body weight.

Michos is available for interviews.

STUDY: DOCTORS 'OVERUSING' COSTLY, RISKIER METHOD FOR CLEARING CLOGGED OR BLOCKED VESSELS

Media Contact:
Michael E. Newman,
mnewma25@jhmi.edu

In a recent study reviewing Medicare claims data from 2019 for nearly 59,000 patients with peripheral artery disease (PAD), a Johns Hopkins Medicine research team provides statistical evidence that one method for restoring blood flow to clogged or completely blocked vessels is being overused or inappropriately used in the United States. This occurs, the researchers say, even though the procedure has not been shown in clinical studies to be more effective than two other less-expensive, less-risky surgical methods.

The findings were reported March 22, 2021, in JACC: Cardiovascular Interventions.

"We wanted to characterize physician practice patterns in treating PAD and determine if the therapy in question, atherectomy, was being used appropriately when compared to the use of balloon angioplasty, stents or a combination of angioplasty and stents," says study lead author Caitlin Hicks, M.D., associate professor of surgery at the Johns Hopkins University School of Medicine. "What we discovered is that although there is a wide distribution of practices across the nation for the use of atherectomies and only slightly more than half of PVIs [peripheral vascular interventions] performed in 2019 relied on the technique, atherectomy accounted for 90% of all Medicare PVI payments."

Atherectomy is one of the methods that clinicians use to remove plaque (the buildup of fat, cholesterol, calcium and other substances found in the blood) from blood vessels that have become narrowed or blocked. Unlike balloon angioplasties and stents that push plaque into the vessel wall to open the passageway, the atherectomy cuts it out.

However, clinical studies have never demonstrated that atherectomies are any more effective in treating PAD than angioplasties, stents or a combination of the two. Other studies have suggested that atherectomy increases the risk of distal embolization, in which a piece of plaque breaks free of a vessel and travels to the legs, dangerously reducing blood flow to the feet.

For the period Jan. 1 - Dec. 31, 2019, the Johns Hopkins Medicine researchers reviewed Medicare fee-for-service claims for 58,552 U.S. patients who received elective PVI -- atherectomy, angioplasty or stenting -- for the first time. Patients were characterized for their demographics -- including age, sex, race and ZIP code of residence -- as well as their reason for getting PVI -- including claudication (pain or cramping in the lower leg due to reduced blood flow) and chronic limb-threatening ischemia (inadequate blood supply to a leg that causes pain at rest or leads to gangrene). Histories of other conditions, such as kidney disease and diabetes, and lifestyle behaviors, such as smoking, also were noted.

Medicare claims for 1,627 doctors who performed PVIs on 10 or more patients during 2019 were reviewed in the study. The researchers documented a number of physician characteristics, including sex, years since graduation from medical school, primary specialty, census region of practice, population density of practice location, number of patients treated for PAD, and the type of medical facility in which care was primarily given.

Analysis of the data showed that during the study period, 31,476 (53.8%) of patients received atherectomies as their PVI. For age and sex, the numbers of atherectomies and non-atherectomies were approximately the same. However, the researchers found that atherectomies were performed more frequently on Black or Hispanic patients, those with claudication as their reason for treatment, and people living in urban settings and in the southern United States.

Physician use of atherectomies ranged from 0% (never used) to 100% (always used), with the latter being the case for 133 clinicians -- nearly 10% of the total studied. Men were more likely to use atherectomies, as were doctors in practice for more than 20 years, cardiologists and radiologists, and those who practiced in regions with a higher median Medicare-allowed payment for PVIs per patient.

Additionally, Hicks says, physicians who worked in ambulatory surgical centers or office-based laboratories used atherectomy seven times more often than physicians who worked primarily in controlled facilities such as hospitals.

Overall, nearly $267 million was reimbursed by Medicare for PVIs performed in 2019. Of this, approximately $241 million -- a resounding 90.2% -- was for atherectomies.

"We feel that these numbers -- especially when there is no solid evidence that atherectomies treat PAD any more effectively than angioplasty, stents or a combination of angioplasty and stents -- suggest there is potential overuse of atherectomies in certain situations," says Hicks. "This poses a high health care burden and should be addressed with professional guidelines for more appropriate use of the procedure."

Hicks is available for interviews.

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