In this study, nationwide insurance claims data was used to assess the impact of changes in hearing aid coverage on year-to-year trends in the number of newly registered hearing impaired people and the number of hearing aid subsidies paid. It turned out that the number of newly registered hearing-impaired persons rose slightly each year, then fell in times of insufficient hearing aid subsidies (from 2004 to 2014) and rose sharply when there was a significant increase in hearing aid subsidies (from 2015). In addition, the proportion of people with newly registered hearing impairment who received hearing aid grants increased to 85.3% in 2015 due to the large increase in the hearing aid grant.
To our knowledge, this is the first official study to assess hearing aid adoption behavior from a nationwide population database. The results show that a realistic hearing aid supply policy can facilitate the rehabilitation behavior of people with hearing impairment.
Hearing loss is the most common chronic condition in the elderly. The number of people with hearing loss worldwide is expected to reach 2.45 billion by 2050, a 56.1% increase from 201911. Unaddressed hearing loss and inadequate hearing rehabilitation reduce quality of life in multiple ways, particularly related to cognitive functioning11, and there has been growing recognition of the societal burden of hearing loss. In order to alleviate the negative effects associated with hearing loss and its consequences, the provision of hearing aids in an audiological clinic is the usual management procedure12. Despite the high prevalence of hearing loss in old age, only a limited proportion of the hearing loss population who could potentially benefit from a hearing aid report current hearing aid use13:14. In the United States, about three quarters of people with hearing loss cannot afford a hearing aid8th. A Korean population study showed that only 17.4% of people with bilateral moderate to profound hearing loss bought a hearing aid, and only about 73% of these people used the hearing aid regularly14. The importance of diagnosing and treating hearing loss tends to be underestimated, particularly in developing countries11.
The average cost of a pair of fitted hearing aids ranged from $2,200 to $7,000 in 2014, and consumer reports show that the median price of a pair of hearing aids was $4,860 in 202115:16. The hearing aid market is controlled by a limited number of companies, and the price of hearing aids is quite high and is considered the first obstacle to hearing aid adoption15:17. In other words, insurance coverage is an important factor in the adoption of hearing aids18. According to data on disability benefits, since 1997 the South Korean government has subsidized part of the cost of buying hearing aids every 5 years. The amount of the hearing aid grant increased from 250,000 won (about 340,000 won (about $300) in 2005 and then tripled to 1,130,000 won (about $1,000) by the end of 2015.
A previous large study in South Korea examined the 10-year trend in the number of people registering with profound hearing impairment from 2006 to 201519. It showed that the trend of hearing loss gradually decreased from 2010 to 201519. Consistent with this report, in the present study, the number of newly registered people with hearing impairment decreased from 2009 to 2013 (Fig. 2A). The decrease in the number of newly registered hearing impaired people could be explained by assuming that most of those motivated by the second subsidy level ($300) may have completed registration within the first 5 years.
However, we have found that the number of newly registered hearing impaired people has skyrocketed from 2015, while at the same time the amount of the hearing aid subsidy has increased. This result suggests that the price of hearing aids has a major impact on hearing aid adoption in South Korea. Another interesting point is that the previous study may have underestimated the actual number of people with hearing loss, as there were likely to have been many unregistered people with hearing loss before a larger hearing aid subsidy was introduced19. To be registered as hearing impaired in Korea, three pure tone audiometry tests and one auditory brainstem response test must be taken, and the cost of these auditory tests is about US$250-US$300. Because the cost of the assessment prior to 2015 was roughly equivalent to the hearing aid subsidy, there was little incentive for people with hearing loss to register as hearing impaired. In addition, the actual value of the hearing aid grant would have steadily decreased over the period 2004-2014 if inflation had been taken into account.
The present study also examined the annual course of severity in newly registered hearing impaired people from 2004 to 2018. The incidence of grade 2 and 3 hearing loss, indicating a profound hearing loss, gradually decreased among the newly registered hearing impaired people, while the proportion of individuals with profound hearing loss (degree of disability 4 and 5) increased (Fig. 3). The mean age of newly registered persons with hearing impairment gradually increased from 2004 to 2015 and increased significantly thereafter (Fig. 5), suggesting that many older persons with hearing loss had not registered before 2015. Hearing aid acceptance fell sharply (Fig 6), suggesting that the primary purpose of registering a disability could usefully be changed to include the introduction of a hearing aid rather than receipt of other hearing disability benefits.
This study showed that reducing the consumer/patient cost of hearing aids by expanding the hearing aid subsidy increased acceptance among people with hearing loss who could benefit from a hearing aid. Following the expansion of hearing aid subsidies, we saw an immediate increase in hearing aid acceptance (Fig. 4). However, besides price, there are many other types of barriers to hearing aid adoption20. In Iceland, national health insurance fully covers the purchase of hearing aids every 4 years, but only 11% of people with hearing loss use hearing aids21. This low acceptance rate of hearing aids can be explained by the complexity of the factors underlying hearing aid use. Hearing aid acceptance is influenced by a complicated interaction between personality, perceived social worth and social stigma20.22.
Several studies have attempted to quantify the financial impact of hearing loss23. A retrospective cohort study in the United States found that the benefits of introducing hearing aids to people who self-report hearing loss are reduced likelihood of emergency room visits and hospitalizations, and reduced Medicare spending17. However, the use of a hearing aid resulted in more visits to the doctor and higher overall health care spending and additional costs17. Another study suggested that providing hearing aids ultimately adds value to the healthcare system and net savings to the Medicare program24. After 2015, people with severe to profound hearing loss could receive a hearing aid grant covering the cost of a single hearing aid under South Korea’s national insurance system. It will be important to monitor whether the expansion of hearing aid provision reduces the loss of quality of life associated with hearing impairment in terms of access to the medical system and leads to a reduction in overall medical expenditure, and this information should be considered for any future changes to provision of hearing aids. Finally, the introduction of a hearing aid does not necessarily mean regular use of the hearing aid14.25. Proper hearing aid fitting, testing, and counseling are important to create an appropriate and effective hearing rehabilitation environment26.
This study has the power of using nationwide population data to examine annual trends in the number of newly registered hearing impaired people in response to changes in hearing aid provision. It successfully identified changes in hearing aid adoption depending on the level of financial support. The study also has limitations, mainly related to the characteristics of the claims data, as they do not include physical examination data such as eardrum status and accurate hearing level. Because the national hearing impaired registration system only includes individuals with severe to profound hearing loss, the present study could not evaluate hearing aid use by individuals with mild to moderate hearing loss. These limitations could be overcome in the future by including other large medical data sources.
In summary, the expansion of Korea’s hearing aid provision system led to a dramatic increase in hearing disability registration and hearing aid adoption, indicating that before the introduction of realistic hearing aid provision, there were many unregistered or untreated hearing loss.