The study results will be presented Monday at the American Auditory Society annual meeting in Scottsdale, Ariz.
"This is very good news for rheumatoid arthritis patients," says Eric Matteson, M.D., Mayo Clinic rheumatologist and senior study researcher. "Patients with rheumatoid arthritis actually have preserved hearing and are no more susceptible to hearing loss than those who do not have the disease; there is no measurable difference with standard testing. This was surprising. I expected to see more hearing loss in rheumatoid arthritis patients."
The study included 29 patients ages 40 to 69 who had rheumatoid arthritis for more than five years, categorized by decades of age. The researchers compared them to 30 participants of the same gender and age categories who did not have rheumatoid arthritis. All participants had comprehensive hearing tests and questionnaires to measure hearing and dizziness handicaps and assess their overall health. Seventeen of 29 patients with rheumatoid arthritis had abnormal hearing for at least one sound frequency (a measure of pitch), as did 14 of 30 of those without rheumatoid arthritis.
Dr. Matteson notes, however, that the findings do not mean that hearing loss is never related to rheumatoid arthritis. "Hearing loss can be a symptom of rheumatoid arthritis, but it doesn't seem to be more of a problem than in the general population," he says.
The researchers found that though no objective difference was detected in comprehensive hearing evaluations of rheumatoid arthritis patients compared to those without the disease, the rheumatoid arthritis patients were more likely to perceive that they had hearing problems. This phenomenon was most pronounced in those who had more severe rheumatoid arthritis and had disabilities due to the disease.
"Perhaps this is due to severe disability and thus an overall feeling of helplessness," says Dr. Matteson. "People who have profound disability may generalize their disabilities to other areas of the body -- they just feel worse overall."
Among the rheumatoid arthritis patients who had hearing loss, most often the loss was partial and due to nerve problems in the inner ear (sensorineural). The cause of this loss is uncertain, but may be due to factors such as noise exposure according to the researchers. In addition, the hearing loss may be related to an autoimmune attack in which the immune system attacks the cochlea, the inner ear cavity containing hair cells and the nerves which connect the cochlea to the brain. The researchers also noted a possible link between the hearing loss and rheumatoid arthritis medications, as patients who took hydroxychloroquine were somewhat more likely to have hearing problems than other study participants.
Critical next steps in this research, according to Dr. Matteson, are a large study of hearing loss among members of the general population with and without rheumatoid arthritis, in addition to a study to assess the impact of rheumatoid arthritis medications on hearing.
The research team also included Christine Halligan, M.D.; Christopher Bauch, Ph.D.; Robert Brey, Ph.D.; Sara Achenbach and William Bamlet, all of Mayo Clinic.