ACC 2017: Aortic valve surgery underutilized in patients with chronic kidney disease

March 17, 2017 – Chronic kidney disease is independently associated with reduced utilization of aortic valve replacement in patients meeting criteria for the surgery, DCRI researchers find.

A large retrospective study involving over 78,000 patients, presented at the 2017 Scientific Sessions of the American College of Cardiology (ACC) by researchers from the DCRI, aimed to analyze the utilization of aortic valve replacement (AVR) in patients with chronic kidney disease (CKD).

“Valvular problems such as aortic stenosis happen more often in those with kidney disease than those who don’t have the dysfunction,” said Zainab Samad, MD, associate professor of medicine, assistant director for research, Duke Echocardiography Lab and lead author of the study.

To treat stenosis or abnormal narrowing of the aortic valve, surgical valve replacement is required. Although less invasive approaches such as a catheter procedure are possible in some cases, surgical aortic valve replacement is the gold-standard treatment for aortic stenosis, Samad said. Researchers analyzed data from the Duke Echo Lab database and linked it to hospital administrative billing and coding databases.

“The Duke Echo Lab database is one of the largest imaging databases in the world,” said Eric Velazquez, MD, professor of medicine and director of Echocardiography Labs and Cardiovascular Imaging at Duke (pictured). “It is unique in its depth of clinical data and outcomes, which allows us to look at clinical outcomes and find relationships with other labs and imaging tests,” he said.

Using the linked datasets, investigators compared patients with CKD who were indicated to get surgery for severe aortic stenosis with patients who did not have CKD but still were indicated to get surgery for aortic stenosis. They used statistical adjustment to nullify the differences in patient characteristics, such as comorbidities, to compare these patients.

The study found that out of 78,059 patients, 890 had severe aortic stenosis of which 84 percent met the criteria to receive aortic valve replacement. Of these patients, more than half had CKD. However, it was found that valve replacement surgery was performed more often in patients without CKD as compared to patients with CKD.

Patients who underwent aortic valve replacement were found to be older and had higher left ventricular ejection fraction as compared to those who did not undergo the surgery. They also had a lower euroSCORE – a risk model which allows the calculation of the probability of death after a heart operation. Even after the team adjusted for comorbidities, patients who had CKD underwent surgery less often than those who did not.

“The findings support what we see clinically, which is that physicians are less likely to refer patients with severe aortic stenosis for valve disease if they have underlying chronic kidney disease,” Velazquez said.

Even though it is known that fixing the aortic valve reduces mortality in patients with kidney disease, who already have a high rate of aortic stenosis, more in-depth analysis is needed to assess whether benefit of surgery outweighs the risks in these patients.

The study was partially funded by the Duke O’Brien Center for Kidney Research.

In addition to the DCRI’s Velazquez and Samad, other researchers included Joseph Sivak and Matthew Phelan of Duke University and Phillip Schulte of Mayo Clinic.

ACC 2017: No racial differences in dual antiplatelet therapy use after percutaneous coronary intervention

March 17, 2017 – Black and white patients had similar rates of dual antiplatelet therapy utilization and adjusted cardiovascular outcomes three years after percutaneous coronary intervention.

A recent study presented at this year’s Scientific Sessions of the American College of Cardiology (ACC) in Washington, D.C. found that while black drug-eluting stent (DES) recipients were younger, had more diabetes, hypertension, and renal disease as compared to white patients, they had similar rates of dual antiplatelet therapy (DAPT) utilization through their first year post-percutaneous coronary intervention (PCI).

“Finding that DAPT use didn’t vary significantly by race is very important,” said Lonnie Sullivan, a medical student at Duke University and first author of the study (pictured). “It verifies that there is no race-driven difference in the care these patients are receiving.”

DCRI and Duke researchers observed data from 915 black and 3,559 white patients who underwent DES placement at Duke University Medical Center between 2005 and 2013. Longitudinally observing patients who received care at Duke for the past several decades, the researchers compared DAPT use at hospital discharge and at follow-up at six months, 12 months, and annually thereafter. Logistic regression was used to model the effects of DAPT use on clinical outcomes post-PCI.

“Premature discontinuation of DAPT may result in stent closure,” Sullivan said. “With this study, we wanted to determine if there was any difference in how DAPT was utilized by race and if this in part explained potential differences in outcomes.”

The study found that black patients who received DES had worse unadjusted cardiovascular outcomes compared to white patients despite the fact that at discharge, there were no notable racial differences in the utilization of DAPT. There were similar rates of revascularization however, as compared to white patients at 36 months. These differences dissipated after adjustment for baseline characteristics.

According to Sullivan, the question still remains as to why black patients receiving DES have more comorbidity at baseline than white patients.

“What we do know is that there are more barriers involved for black patients in receiving care,” he said.

The study also specifically looked at DAPT utilization but researchers were unable to assess adherence beyond self-report, thus there was no definitive way of determining whether patients had missed doses.

“Educating patients on the importance of compliance as soon as they are started on DAPT is one of the most important interventions that we can implement,” Sullivan said. “Being able to adequately control existing cardiovascular risk factors will also go a long way in improving outcomes.”

In addition to Sullivan, other researchers included the DCRI’s Hillary Mulder, Karen Chiswell, Linda Shaw, Tracy Wang and Kevin Thomas.

Fewer opioids over more time linked to lower costs, better outcomes

March 17, 2017 – The findings may point the way toward better strategies for reducing opioid abuse.

Providing fewer total opioids over a longer period of time is associated with lower overall costs and utilization for hip surgery patients, according to a new study by DCRI researchers.

With opioid overdoses and abuse a subject of growing concern for public health agencies, the Centers for Disease Control issued a series of guidelines in 2016 intended to improve communication between clinicians and patients about the risks and benefits of opioid drug therapy. While these guidelines included recommendations for acute, general surgery opioid management, there has been little research into management strategies for intermediate- to long-term post-surgical musculoskeletal pain.

In an observational cohort study, the DCRI’s Chad Cook, PhD (pictured), and his colleagues sought to analyze post-operative opioid prescription strategies and measure direct and indirect health care utilization and costs in individuals undergoing non-arthroplasty orthopedic hip surgery.

The study appears in the current issue of the journal Substance Abuse Treatment, Prevention, and Policy.

Using data from the Military Health System Data Repository (MDR), which serves as the centralized data repository for all Defense Health Agency corporate health care data, the researchers identified 1,219 patients who received hip surgery between 2003 and 2015.The dataset included information on opioid management for 12 months before and 24 months after surgery.

Using cluster analysis, Cook and his study team then identified two distinct post-operative opioid prescription subgroups: patients who received a high total number of opioids over a short period of time (850 patients), and those who received fewer total opioids over a longer period of time (369 patients).  The researchers then used linear mixed effects modeling to examine opioid prescription pattern subgroups and identify subgroup differences in health care utilization and costs.

The overall trend was that the subgroup prescribed more opioids over a shorter duration had more pre-operative comorbidities, opioid prescriptions, and total days of opioid pain medications. That subgroup was also younger and had higher proportions of heavy preoperative health care utilization. Noting that this finding ran counter to their hypothesis, the researchers posited four possibilities for this outcome: that the findings are reflective of pre-operative comorbid conditions; that the subgroup receiving more opioids over a shorter amount of time was associated with the preoperative opioid use patterns of its patients; that the subgroup receiving fewer opioids over a longer amount of time benefited more from opioids by receiving adequate pain management; and that higher costs and utilization are associated with increased incidences of side effects in the subgroup receiving more opioids over a longer amount of time.

These findings, Cook said, illustrate the need for randomized trials to better understand the effectiveness of opioid prescription patterns on reducing side effects and minimizing the chances of opioid abuse.

“We need to start looking at patterns of treatment,” he said. “We couldn’t find anything in the literature about other musculoskeletal conditions or postsurgical conditions. This topic is essentially unstudied.”

In addition to Cook, the study’s authors included Daniel I. Rhon, Brian D. Lewis, and Steven Z. George.

Reducing radiation could safely cut breast cancer treatment

March 15, 2017 – A shorter regimen is scientifically sound, but most women still get the longer therapy.

More than half of older women with early stage breast cancer received more radiation therapy than what might be medically necessary, adding additional treatment and health care costs, according to a study by Duke Cancer Institute and DCRI researchers.

The researchers found that the annual estimated cost for radiation therapy in women older than age 50 who were potentially eligible to cut back or eliminate the treatment was $420.2 million in 2011. Had this group of women been treated with the alternative approaches that evidence suggests are as effective, the cost was estimated at $256.2 million – a potential savings of $164 million.

“It’s important to look for opportunities in cancer treatment where we can safely reduce health care costs without compromising excellent outcomes,” said Rachel A. Greenup, MD, assistant professor of surgery and lead author of a study published March 14 in the Journal of Oncology Practice.

“Our study provides an example of a win-win situation, where patients can receive high-quality, evidence-based cancer care while also reducing the treatment burden for patients and the health care system,” Greenup said.

Greenup and colleagues, including senior author E. Shelley Hwang, MD, chief of breast surgery at the Duke Cancer Institute, used 2011 data from the National Cancer Database to identify more than 43,000 breast cancer patients aged 50 and older. All had small tumors that had not spread to the lymph nodes, and had been treated with lumpectomy.

Previous studies have shown that these patients can do equally well when treated with a four-week course of breast radiation, as opposed to the traditional six-week regimen. An additional study demonstrated that carefully selected patients aged 70 and older had no additional survival benefit with radiation therapy when treated with tamoxifen after lumpectomy.

Despite the published evidence, however, the Duke-led researchers found that 57 percent of patients who were potentially eligible to reduce or forego radiation still received the longer, costlier regimens.

Using Medicare reimbursement data, the researchers estimated that the cost per patient for the conventional, six-week radiation therapy was more than $13,000. That compared to a little more than $8,000 for the shorter regimen or no cost when radiation is eliminated.

Greenup said the financial analysis of cost savings in the study was limited because Medicare data do not provide as much information as insurance data, which were not available for this study. Additionally, she said, the available patient data do not provide reasons why women underwent the longer, costlier radiation treatments. In many instances, the treatment might have been warranted based on factors that were not evident in the database, or patients might have been uncomfortable reducing or omitting radiation.

Greenup said the study nonetheless highlights the need to apply evolving evidence to treatment decisions.

“Breast cancer treatment costs are projected to reach $20 billion in 2020,” Greenup said, citing National Cancer Institute statistics. “Of course high-quality care is the priority in cancer treatment, but our study suggests that utilization of evidence-based radiation treatment can translate into reductions in health care spending without sacrificing quality.”

In addition to Greenup and Hwang, study authors include Rachel C. Blitzblau, Kevin L. Houck, the DCRI’s Julie Ann Sosa, Janet Horton, Jeffrey M. Peppercorn, Alphonse G. Taghian, and Barbara L. Smith.

The study received funding support from the Building Interdisciplinary Research in Women’s Health award from Duke.

Most atrial fibrillation patients don’t get preventive drug before stroke

March 14, 2017 – Anticoagulants were not used according to guidelines, despite evidence they prevent strokes.

More than 80 percent of stroke patients with a history of atrial fibrillation either received not enough or no anticoagulation therapy prior to having a stroke, despite the drugs’ proven record of reducing stroke risk, according to a DCRI study.

Reporting in the March 14 issue of the Journal of the American Medical Association, the researchers also found that when patients did receive recommended anticoagulation drugs, they had less severe stroke outcomes and less risk of dying.

“Atrial fibrillation is very common, and people with the condition are at a much higher risk of having stroke,” said lead author Ying Xian, MD, PhD, assistant professor of neurology at Duke and member of the DCRI. “Treatment guidelines call for these patients to receive an anticoagulant such as warfarin at a therapeutic dose or a non-vitamin K antagonist oral anticoagulant (NOAC), so it’s surprising that this is not occurring in the vast majority of cases that occur in community settings.”

The study included more than 94,000 patients with atrial fibrillation from the American Heart Association’s “Get With The Guidelines-Stroke” registry who had had an acute ischemic stroke. The analysis was sponsored by the Patient-Centered Outcomes Research Institute to inform patients, physicians and others about optimal stroke care.

The researchers found that only 16 percent of patients with atrial fibrillation had received the recommended anticoagulation medication prior to having a stroke. These medications include therapeutic levels of warfarin or NOAC.

A total of 84 percent of patients were not treated according to the guidelines prior to stroke:

  •  30 percent were not taking any antithrombotic treatment at all;
  • 40 percent were taking an antiplatelet drug such as baby aspirin or clopidogrel;
  • 13.5 percent were on warfarin, but at a level that was not considered therapeutic at the time of their stroke.

“While some of these patients may have had reasons for not being anticoagulated, such as high bleeding or fall risk, more than two-thirds had no documented reason for receiving inadequate stroke prevention therapy,” Xian said.

Xian added that in those rare cases where anticoagulation failed to prevent a stroke, patients who were taking the therapy showed a tendency to have less severe strokes, with less disability and death.

“These findings highlight the human costs of atrial fibrillation and the importance of appropriate anticoagulation, Xian said. “Broader adherence to these atrial fibrillation treatment guidelines could substantially reduce both the number and severity of strokes in the U.S. We estimate that between 58,000 to 88,000 strokes might be preventable per year if the treatment guidelines are followed appropriately.”

In addition to Xian, study authors include Emily C. O’Brien, Li Liang, Haolin Xu, Lee H. Schwamm, Gregg C. Fonarow, Deepak L. Bhatt, Eric E. Smith, DaiWai M. Olson, Lesley Maisch, Deidre Hannah, Brianna Lindholm, Barbara L. Lytle, Michael J. Pencina, Adrian F. Hernandez, and Eric D. Peterson.

This received funding support from the Patient-Centered Outcomes Research Institute (CE-1304-7073).

Pokémon Go appears to encourage sedentary people to get up and go

March 8, 2017 – A small study shows that the interactive game prompted people to walk more steps a day.

The Pokémon Go craze that spurred millions of people to collect virtual monsters via a smart phone app might have also had a health benefit by encouraging people to get up and walk.

A small study at Duke Health found that some people who played the game added thousands of steps a day. The finding — presented at the American Heart Association’s Epidemiology and Prevention / Lifestyle and Cardiometabolic Health meeting in Portland, Ore. — suggests that it’s possible to design fun ways to increase physical activity.

“Lack of enjoyment and lack of time are the most common reasons for not being physically active,” said lead author Hanzhang Xu, a PhD student at Duke University School of Nursing. “So incorporating physical activity into the gameplay on mobile devices could provide an alternative way to promote physical activity.”

The Duke team recruited 167 iPhone users who had played Pokémon Go in July 2016. The researchers designed an online survey and asked participants to provide screenshots of their daily steps reported by the iPhone Health app between June 15 and July 31, 2016. They then compared their daily steps before and after playing Pokémon Go.

They found that participants were twice as likely to reach 10,000 steps a day after playing Pokémon Go than they were before playing the game. The percentage of days in which the 10,000-daily step goal was reached increased from 15.3 percent before playing Pokémon Go to 27.5 percent after playing the game.

The findings were particularly encouraging among participants who had low activity levels or were overweight before playing Pokémon Go, with these players adding nearly 3,000 steps a day after playing the game.

“We think our study could have implications for the design of other digital health interventions that encourage people to exercise more,” Xu said.

In addition to Xu, study authors include Ying Xian, Haolin Xu, Li Liang, Adrian F. Hernandez, Tracy Y. Wang and Eric D. Peterson. The study was funded by the DCRI.

Clinical Infectious Diseases highlights the work of ARLG

March 2, 2017 – A recent supplement of the journal focuses on the work of the group, which is facilitated by the DCRI.

Clinical Infectious Diseases, one of the most widely cited journals in its field, has devoted an entire supplement to the Antibacterial Resistance Leadership Group (ARLG).

The ARLG develops, designs, implements, and manages a clinical research agenda to increase knowledge of antibacterial resistance. It aims to advance research by building transformational trials that will change clinical practice and reduce the impact of antibacterial resistance and antimicrobial resistance. The ARLG is facilitated by the DCRI and works under the centralized leadership of an executive committee and two principal investigators: the DCRI’s Vance Fowler, MD, MHS (pictured), and Henry ‘Chip’ Chambers, MD, of the University of California, San Francisco.

The issue of Clinical Infectious Diseases includes articles from ARLG members and others describing many of the group’s current projects.

“The ARLG is an example of a successful public–private partnership that has driven research on the wide array of issues related to antibiotic resistance, and it is well positioned to continue playing a critical role in the United States and through global collaborations with other groups,” writes Barbara E. Murray of the University of Texas Health Sciences Center and Amanda Jezek of the Infectious Diseases Society of America in their introduction to the issue.

Proteins in your runny nose could reveal a viral infection

March 1, 2017 – A new study could lead to a simple test that will determine the source of upper respiratory illnesses.

It may seem obvious, but the key to confirming whether someone is suffering from a cold or flu virus might lie at the misery’s source — the inflamed passages of the nose and throat.

Duke Health scientists have identified a group of proteins that, when detected in specific quantities in the mucous, are 86 percent accurate in confirming the infection is from a cold or flu virus, according to a small, proof-of-concept trial published online in the journal EBioMedicine.

The researchers hope their initial work identifying the protein signature could aid the development of a quick, noninvasive doctor’s office test to determine the cause of upper respiratory illness and appropriate treatment.

“Every day, people are taking time off from work, going to emergency rooms, urgent care or their primary care doctors with symptoms of an upper respiratory infection,” said Geoffrey S. Ginsburg, MD, PhD, a senior author of the paper and director of the Duke Center for Applied Genomics & Precision Medicine (DCAGPM), which led the study. “Looking for these proteins could be a relatively easy and inexpensive way of learning if a person has a viral infection, and if not, whether the use of antibiotics is appropriate.”

Although upper respiratory infections are among the most common reasons people visit the doctor in the U.S., health care providers lack tools to distinguish between a bacterial infection that might warrant antibiotics and a viral infection that would instead call for symptom relief.

Widespread use of antibiotics for upper respiratory infections doesn’t benefit patients with viral illness and can contribute to antibiotic-resistant superbugs, Ginsburg said. More precise diagnoses of these infections could be another tool to curb the development of superbugs, he said.

For the trial, researchers infected 88 healthy adult volunteers with a common strain of cold or flu virus.

Some participants didn’t get sick. Among those who developed infections, researchers found a distinct set of 25 proteins in fluid samples they gathered by flushing about 2 teaspoons of saline through the participant’s nasal passages.

Duke researchers in genomics and precision medicine have spent the past decade exploring strategies for differentiating bacterial and viral infections with the goal of developing cost-effective diagnostic tools doctors could use in their offices.

“In the past, science has focused on identifying the pathogen someone is infected with in the blood or other sample,” said lead author Thomas Burke, PhD, director of technology advancement and diagnostics at the DCAGPM. “Our approach flips the paradigm of how we look for infection. Instead of looking for the pathogen, we study the individual’s response to that pathogen and signature patterns in their genes, proteins, metabolites and other biomarkers.”

The Duke team has previously explored blood tests to examine a patient’s RNA for gene signatures to distinguish bacterial and viral infections in the upper respiratory tract and is working with a private company to develop potential diagnostics.

Analyzing proteins in mucous is a less invasive approach and requires less processing than blood samples. The researchers hope additional studies verify the initial results and lead to the development of a paper-based test that could be used in doctor’s offices or even at home to determine whether a doctor’s visit is necessary, said Christopher Woods, MD, a senior author, member of the DCRI, and associate director of applied genomics at the DCAGPM.

“The protein targets offer a faster, more cost-effective model for rapid screening and diagnoses of viral infections,” Woods said. “If the data are verified, the model could be valuable in many circumstances, such as rural settings or developing countries with less convenient access to health care, or even as an airport screening tool during an outbreak of a particularly threatening strain of flu.”

In addition to Ginsburg, Woods and Burke, study authors included Ricardo Henao; Erik Soderblom; Ephraim L. Tsalik; J. Will Thompson; Micah T. McClain; Marshall Nichols; Bradly P. Nicholson; Timothy Veldman; Joseph E. Lucas; M. Arthur Moseley; Ronald B. Turner; Robert Lambkin-Williams; and Alfred O. Hero III.

New stroke quality improvement initiative targets center of the “stroke belt”

February 17, 2017 -The IMPROVE Stroke Care program aims to improve every element of stroke care in North Carolina

A new DCRI-led program is looking for ways to improve systems of stroke care across North Carolina and beyond.

Stroke kills more than 130,000 Americans each year, making it the fifth-leading cause of death in the nation. Every year, more than 795,000 people in the United States have a stroke. Many of these strokes occur in the southeastern United States, in an 11-state region known as “the stroke belt.” North Carolina, which occupies the middle of this region, is sometimes described as the “buckle” of the belt.

In early 2015, the American Heart Association/American Stroke Association (AHA/ASA) updated their guidelines to recommend endovascular therapy in eligible acute ischemic stroke patients. However, for this therapy to be of benefit for the largest number of stroke patients, integrated and coordinated systems of care need to include public stroke awareness and education, patient and family recognition of stroke, and carry through rapid Emergency Medical Services  access and transportation to the appropriate inpatient setting and beyond.

Early action is important for improving outcomes for stroke patients. Patients who arrive at the emergency room within 3 hours of their first symptoms often have less disability three months after a stroke than those who received delayed care. Ensuring rapid care in North Carolina is particularly difficult, however, as there are only four certified comprehensive stroke centers in the state.

The IMPROVE Stroke Care program was created to develop a regional integrated stroke system in North Carolina that identifies, classifies, and treats patients with acute ischemic stroke more rapidly and effectively with reperfusion therapy. Based on similar programs developed to improve systems of care around heart attacks, IMPROVE Stroke Care will develop a network of stroke centers and other hospitals to implement best practices and integrate state of the art technologies into regional systems of stroke care. The DCRI’s System and Implementation Research and Outcomes operations teams will provide expertise in health system engineering and data reports to share across the program to improve process and clinical outcomes.

The initial costs of the program will be funded through a series of philanthropic grants from various sources totaling $3 million. The DCRI’s Bradley Kolls, MD, PhD (pictured left), and Carmen Graffagnino, MD (pictured right), medical director of the Duke Comprehensive Stroke Center, will serve as principal investigators for the project.

One of IMPROVE Stroke Care’s novel elements is the use of new data capture technologies. Key data elements will be defined, collected, and fed back in real time to drive practice improvement. Participating centers will have real-time feedback on their performance metrics, utilizing novel data capture methods and mobile applications that operate independently of existing electronic health records or primary databases but are able to interact with them. This approach is based on earlier work done by the Duke Telestroke Network, which provides remote consultations for acute stroke diagnosis and treatment recommendations to affiliates across the state.

“We’ve come up with an innovative way of capturing data automatically through the Telestroke Network,” Kolls said. “This is a new strategy for collecting data on the systems of care throughout the state.”

The investigators also noted that stroke care has enormous financial costs; the total direct cost of stroke in the United States is expected to reach $184 billion in 2030. Initiatives such as IMPROVE Stroke Care save millions of dollars through reduced disability, improved functional outcomes, as well as reduced nursing home and re-hospitalization costs.

Ultimately, Graffagnino said, the real value of IMPROVE Stroke Care is in bringing together experts from every field of stroke care to address one of the Stroke Belt’s most serious public health threats.

“This is the whole village getting to solve this problem, not just doctors,” he said. “I think that’s really important.”

More extremely preterm babies survive, live without neurological impairment

February 16, 2017 – Overall survival and development of infants born at 23, 24 weeks improving, study finds.

Babies born at just 22 to 24 weeks of pregnancy continue to have sobering outlooks — only about 1 in 3 survive.

But according to a new study led by Duke Health and appearing Feb. 16 in the New England Journal of Medicine, those rates are showing small but measurable improvement. Compared to extremely preterm babies born a decade earlier, the study found a larger percentage are developing into toddlers without signs of moderate or severe cognitive and motor delay.

Changes to prenatal care, including greater use of steroids in mothers at risk for preterm birth, could have contributed to increased survival and fewer signs of developmental delay in these infants, the authors said.

“The findings are encouraging,” said lead author Noelle Younge, MD, a neonatologist and assistant professor of pediatrics at Duke. “We see evidence of improvement over time. But we do need to keep an eye on the overall numbers, as a large percentage of infants born at this stage still do not survive. Those who survive without significant impairment at about age 2 are still at risk for numerous other challenges to their overall health.”

The researchers analyzed the records of 4,274 infants born between the 22nd and 24th week of pregnancy, far earlier than the 37 to 40 weeks of a full-term pregnancy. The babies were hospitalized at 11 academic medical centers in the Neonatal Research Network, part of the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the National Institutes of Health.

About 30 percent of infants born at the beginning of the study (between 2000 and 2003),  survived. That proportion increased to 36 percent for babies born toward the end of the study (from 2008 to 2011), with the best outcomes for children born at 23 and 24 weeks. Overall survival for babies born at 22 weeks remained the same throughout the study, at just 4 percent.

Over the 12-year study period, the proportion of infants who survived but were found to have cognitive and motor impairment at 18 to 22 months stayed about the same (about 14 to 16 percent). But the proportion of babies who survived without evidence of moderate or severe neurological impairment improved from 16 percent to 20 percent.

“Researchers in the Neonatal Research Network reported in 2015 that survival was increasing in this vulnerable population,” Younge said. “One concern was that the improved survival might have been accompanied by a greater number of infants who went on to have impairments in the long term, such as cerebral palsy, developmental delay, hearing and vision loss. However, we actually are seeing a slight improvement. Because children continue to develop over years, it’s important to continue to track this data so families and providers can make the best decisions in caring for these infants.”

Improvements in survival and neurodevelopment may be the result of a number of factors, including declining rates of infection in the infants, along with the increased use of steroids in expectant mothers that can help mature and strengthen the fetus’s lungs prior to birth. At the beginning of the study, 58 percent of the expectant mothers had received steroids to boost fetal development. That figure increased to 64 percent by the end of the study.

“The culture of neonatal intensive care units has really changed in the past decade,” said senior author C. Michael Cotten, MD, a neonatologist and professor of pediatrics at Duke.  “We’ve taken a big focus on preventing infections, and there’s a lot more encouragement and support for the use of mother’s milk than there was 15 years ago, which has also been linked to better outcomes.”

Extremely preterm infants are highly susceptible to infections. Neonatal intensive care units have reported steady decreases in infection rates among extremely preterm infants over the past two decades.

“This is important because infections have been associated with greater risk of neurologic problems,” Cotten said.

In addition to their work with the Neonatal Research Network studying strategies to improve outcomes for preterm babies, the Duke researchers continue to study environmental and genetic factors, as well as the babies’ gut bacteria and metabolomics.

“We’re are always looking at how we can make further headway and continue to improve survival and reduce illness in this population,” Cotten said. “The results of this study are encouraging, but there’s still a long way to go.”

In addition to Younge and Cotten, study authors were Ricki F. Goldstein; Carla M. Bann; Susan R. Hintz; Ravi M. Patel; P. Brian Smith; Edward F. Bell; Matthew A. Rysavy; Andrea F. Duncan; Betty R. Vohr; Abhik Das; Ronald N. Goldberg; and Rosemary D. Higgins.