What If Treating Hearing Loss Delays Cognitive Decline?
For this week’s Oaktree TV, I interviewed Dr. Nick Reed of Johns Hopkins to talk about the research that his team is working on around the effects of age-related hearing loss through a public health lens. It was one of the most fascinating interviews I’ve conducted, as the implications from his team’s research are pretty vast. So, for today’s update, I thought I’d break out some of the key talking points from our discussion.
What are the geriatric outcomes that come with age related hearing loss?
As an audiologist himself, Nick points out that much of the focus of audiology is around the immediate outcomes – hearing loss & communication, and how the patient is satisfied with hearing aids. What Nick and his team are doing is they’re examining the longer term outcomes, such as cognitive decline, dementia, depression, social isolation, and loneliness. The things that gerontologists tend to focus on.
The Johns Hopkins research team studying this has found that, in general, people with hearing loss have a faster rate of cognitive decline compared to those without hearing loss (factoring in a number of controls such as age, race, sex, hypertension, etc). In one study, the team followed a group of 600 older adults over a 12 year period, and at baseline none of these adults has dementia. The team found that over the 12 year period, those with mild hearing loss had a 2X risk of developing dementia, moderate hearing loss 3X risk, and those with severe hearing loss had a 5X risk.
In a separate study, the team studied 150,000 individuals, half with hearing loss and half without, across a 10 year period and matched those with hearing loss to those without. What they found is that those with hearing loss tended to spend on average about $22,000 more on healthcare spending. In addition, those with hearing loss had a 44% higher risk of having a 30-day readmission, 46% higher rate of hospitalization, and a 17% higher risk of emergency department visits.
So, through these studies, the Johns Hopkins team has found that hearing loss tends to equate to higher healthcare costs, more hospitalization, and increases the risk of comorbidities, such as cognitive decline and dementia. Some of these finds were probably suspected among some in the hearing healthcare community, and the Johns Hopkins team validates those suspicions.
What is the impact of treating hearing loss on the outcomes listed above?
As Nick mentions, this is the million dollar question. As Nick lays out to me in the video, the reason this is such a tough question to answer lies with the secondary data and the fact that people with hearing aids usually have the means to buy hearing aids and are more conscious of their health. In other words, these are probably the type of people that are being proactive with their health, which would impact something such as cognitive decline.
In order to answer this million dollar question, Nick tells me that what they need are large scale randomized trials. Fortunately, Johns Hopkins has such a study currently underway to understand whether or not treating hearing loss delays cognitive decline. The two-sided study compares one side, where the individuals are using hearing aids, to the other side, where the individual is not getting a placebo, but rather, sees a nurse and focus on age-related outcomes such as staying active, reduce smoke and improving diet. So the team is comparing two sides that are both receiving beneficial treatment, the question though is whether one side is more effective than the other.
As we wait for the results of the Johns Hopkins study around this important question, Nick cites other studies, such as Piers Dawes research, that add evidence that treating hearing loss with hearing aids does in fact delay cognitive decline. What Dawes’ team found, was that for individuals with a declining slope of cognitive ability, once intervened with hearing aids, the angle changed in its trajectory to not be nearly as steep as before. According to Dawes’ team, “one reason for why hearing aids would delay the rate of cognitive decline is the ‘cascade hypothesis,’ in which hearing aids may reduce depression, promote cognitively stimulating social engagement, promote greater physical activity and/or self-efficacy, all of which protect cognitive function.”
To me, if more and more evidence were to pile up to say that hearing aids have the benefit of reducing the rate of cognitive decline, that would truly be a game-changer. I believe this would change the status of a hearing aid from a “nice to have” from a “need to have” and therefore be viewed as such by our healthcare system, strengthening the argument that these devices warrant insurance coverage by moving it out of the “elective” status it’s currently confined to. Additionally, I think that this type of finding would alter how general physicians’ view hearing aids, and be viewed by the GP as one of few “remedies” available to prescribe to older adults who are showing signs of cognitive decline. This would likely equate to more referrals.
We know that hearing loss leads to higher healthcare costs, more frequent hospitalization and an increase in certain cognitive-related comorbidities. Teams like Nick’s are working to research if hearing aids are in fact one of the best solutions available to reduce all three, which would be a huge boon to older adults with hearing loss, the hearing healthcare professional, and the healthcare system as a whole.
-Thanks for Reading-