While both cardiovascular diseases and hearing loss are generally considered more prevalent in the older population, two recent studies on the link between heart and hearing health show that the proven connection exists in both ends of the life cycle, sending a new set of red flags to audiology professionals working with the most vulnerable of their patients.
Various research shows that 1.4 out of 1,000 newborns have hearing loss. It is believed that non-genetic factors—from nervous system/brain disorders to premature birth to ototoxic medications (usually illicit substances) used by the birth mothers to maternal diabetes—lead to approximately 25 percent of hearing loss.
Meanwhile, 50 percent was generally attributed to genetic factors, with the most common cause (70 percent) being autosomal recessive hearing loss, meaning that each parent carried a recessive gene without having hearing loss themselves.
Within the other 25 percent, there were causes such as a perforated eardrum, exposure to a loud noise, or infections.
Relatively understudied was the connection with heart issues in infants. Nancy B. Burnham, CRNP, MSN, CCRC, a research nurse in the department of cardiothoracic surgery at The Children's Hospital of Philadelphia (CHOP), headed a team that sought to boldly go where no researchers had gone before and make the connection. The results of the study initially appeared in the January 2017 issue of the Journal of Pediatrics.
Evaluations—audiological and neurodevelopmental—were conducted on 348 children who underwent repair of congenital heart disease at the Children's Hospital of Philadelphia as part of a prospective study evaluating the patients’ neurodevelopmental outcomes at 4 years of age. A prevalence estimate was calculated based on the presence and type of hearing loss. From there, potential risk factors and the impact of hearing loss on neurodevelopmental outcomes were evaluated.
Burnham said that she and the other researchers were somewhat surprised by the prevalence in children—20-fold higher than in one percent seen in the general population of infants—with heart problems requiring open heart surgery who are at risk of hearing loss in childhood.
Younger gestational age, the presence of a genetic anomaly, and longer postoperative duration of stay were associated with hearing loss. Hearing loss was also associated with worse neurodevelopmental outcomes.
“We didn't think we would see such a high prevalence, but it makes sense in the context of other groups, like the risk of hearing loss in the premature baby,” said Burnham. “I was particularly interested in the presence of both unilateral and high-frequency hearing loss because it can be missed by the family and in the school setting.”
The results of the study are vital, as detecting hearing loss as early as possible—within six months of birth instead of two years, when many toddlers are diagnosed because they are not communicating properly—has been proven to produce better outcomes.
Carol Knightly, AuD, the primary audiologist of the study on infants with heart surgery and hearing loss and the senior director of the Center for Childhood Communication at CHOP, considers this as being at the core of the study.
“The real take-home here is once hearing loss occurs, the earlier we can identify the loss and begin intervention,” said Knightly. “If that hearing loss is present at birth or occurs shortly after, then we should work to stay within the identification and intervention process starting at 6 months of age.”
“Children born with life-threatening heart defects require a great deal of sophisticated care before and after surgery,” added Burnham. “This study reminds health care providers not to overlook hearing evaluations because early detection and intervention can reduce later problems in neurodevelopment.”
HEART FAILURE AND HEARING LOSS
In recent years, the Better Hearing Institute (BHI) reported that cardiovascular disease was a contributing factor to hearing loss and that it should be viewed as a warning sign of life-threatening cardiovascular events such as heart attack or stroke.
While heart failure and heart attack are both forms of heart disease and have common causes, it is an accepted medical fact that they are not the same.
While heart attacks are sudden because of a blockage cutting off blood flow, heart failure is a chronic condition that develops—and gets worse—gradually.
Madeline R. Sterling, MD, MPH, was the lead author of a recent study on older adults with heart failure using data from the National Health and Nutrition Examination Survey (NHANES). It focused specifically on hearing loss in connection with heart failure, a chronic and incurable condition that is the leading cause of hospitalization among older adults.
With roughly 5.8 million people in the United States diagnosed with heart failure, Sterling foresees this number rising with the aging population. Along with the diagnosis, patients are asked to manage their conditions with medications, a low-salt diet, and weight monitoring in terms of fluid changes.
“To follow these instructions, patients with heart failure need to be able to hear them,” warned Sterling. “The study is important because much of heart failure management revolves around effective patient and provider communication. If a large percentage of the patient population can't hear the doctor and is not using hearing aids, that is a problem.”
The study—in which Sterling was joined by Frank Lin, MD, PhD; Adele Gorman, PhD; Sandra E. Echeverria, PhD, MPH; and Monika M. Safford, MD—analyzed data from adults over the age of 70 in 2005 and 2006 and again in 2009 and 2010, and revealed that older adults with heart failure have an 11.1 percent greater chance of developing hearing loss and 1.67 greater odds of more intense hearing loss.
The research results revealed another jaw-dropping gap, as it suggested that 75 percent of older adults with heart failure have hearing loss, but in this population, only 16.3 percent of those who wear hearing aids.
“This was alarming for us, since much of heart failure management requires that patients hear and understand physician recommendations,” said Sterling. “The finding that so few patients with this sensory deficit use hearing aids was not alarming since other studies of older adults have found similar findings—that many people who have hearing loss don't use hearing aids. The reason for this is multifactorial, but some include issues with access to devices and cost.”
AUDIOLOGY PROFESSIONALS FRONT AND CENTER
While Sterling pointed toward the need for all health care providers—doctors, nurses, etc.,—to be aware that hearing loss is highly prevalent among older adults with heart failure, audiology professionals are the last line of defense.
“Audiologists are critical because they are often the ones who assess patients for hearing loss,” said Sterling. “With this, they provide opportunities for counseling around the findings and for discussing treatment options with patients.”
Sterling also identified another area of importance: direct communication with audiology professionals by those medically treating patients. This assures that less will be lost in translation.
“It is also important that physicians communicate with audiologists before and after the hearing assessment,” said Sterling. “Adults with heart failure are often older with some degree of cognitive impairment and may not be able to communicate their medical history fully to the audiologists. In addition, physicians may be able to provide audiologists with details about a patient's social support system at home and ability to pay for devices. Audiologists, in turn, can help the physician understand the results of the assessment and what the degree of hearing loss will mean to the patient. This back-and-forth communication will allow for a patient-centered plan of care.”
When it comes to those at the front end of the life cycle, Knightly is vigilant. She keeps a copy of the Joint Committee on Infant Hearing Loss (JCIH) mission statement in her office as a reminder of the important role audiologists play in following up with the families of infants who are at risk.
“I re-read it and reference it frequently,” she said of the mission statement. “I think that's important, regardless of the practice setting—anytime we have an opportunity to discuss early identification and management of hearing loss. It's also important for us as audiologists to remember that physicians and surgeons aren't necessarily familiar with risk indicators for hearing loss, so it's incumbent upon us to ensure that they have the information they need to ensure appropriate follow-up.
“The message should be that early identification—followed by prompt intervention—yields far superior outcomes for children with hearing loss. However, I think there's an additional message here–that we can't be complacent about hearing loss occurring at any time during childhood. We know that at least some of the children in this study passed their newborn hearing screening prior to any surgery. It's surprising how many professionals rely solely on those results and aren't familiar with risk indicators for later-onset hearing loss.”
Aware that cost has been an issue in the past, Sterling believes the Over-the-Counter (OTC) Hearing Aid Act, passed in 2017, will greatly benefit older Americans on fixed incomes who have mild to moderate hearing loss.
“Pointing patients towards more affordable devices is the key” said Sterling. “Additionally, making sure that the findings from an audiologist exam get back to the primary care doctor and/or cardiologist is key. Many people with hearing loss are often embarrassed and tend not to bring it up with their doctors. Doctors can take the time to ask patients about their hearing, but should also improve their own communication techniques to communicate effectively with these patients.”
Moving forward, Sterling believes that the results of the study are just the beginning of improving the quality of life for older adults with both heart failure and hearing loss.
“Because this was a cross-sectional, observational study, our results cannot speak to causality or the exact underlying pathophysiology between heart failure and hearing loss,” she explained. “I think one of our next steps is to do analyses to try to understand the association we found. There are a lot of chronic diseases in which hearing loss is more common than in the general, healthy population, including coronary heart disease, hypertension, and diabetes. Many adults with heart failure also have these conditions. One thing that we do not yet know, though, is if there are other things, unique to having heart failure, that lead to this elevated prevalence of hearing loss. Examples include side effects of heart failure medications, heart failure-specific pathophysiology, etc.”
Burnham believes the study involving infants will be an important baton to hand to future researchers in a relay race against time. That said, she was able to pinpoint some possible areas of cause and effect.
“There might be modifiable factors, but additional research would be required,” she said. “Duration of stay is a potential area of research. What about how longer length of stay increases risk for hearing impairment? Perhaps the many ototoxic drugs they receive during their hospital stay is a potential mechanism for future study. Research has shown babies with congenital heart disease brains are more immature than their associated gestational age at birth. If there were measures that would reduce pre-term or near-term births, these might have an impact.”
Thoughts on something you read here? Write to us at HJ@wolterskluwer.com.