Low-Frequency Conductive Hearing Loss Common in Ankylosing Spondylitis

Among individuals with ankylosing spondylitis (AS), mild low-frequency hearing loss is common and is more likely to be conductive rather than sensorineural, according to study results published in the International Journal of Rheumatic Diseases.

This cross‐sectional, observational study included 100 individuals (mean age, 32±12 years; 96 men) with AS and 40 control participants and took place in a tertiary referral center in northern India. The researchers defined hearing loss as ≥20-dB pure-tone thresholds in at least 2 frequencies of the audiogram, with severity defined by World Health Organization standards. They collected data including disease duration, age at onset of disease, sex, and current age, and used the Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Metrology Index, and Bath Ankylosing Spondylitis Functional Index to measure disease activity. The researchers also recorded the dosage of nonsteroidal anti-inflammatory drugs (NSAIDs).  They used student’s t tests to compare continuous variables and Fisher’s exact test to compare categorical variables.

The mean disease duration among the population with AS was 8.2±6 years. The median Bath Ankylosing Spondylitis Disease Activity Index score was 3.5±2.2, the Bath Ankylosing Spondylitis Functional Index score was 3.7±2.6, and the Bath Ankylosing Spondylitis Metrology Index score was 2.75±2. Cumulative NSAID dose was higher among individuals with hearing loss, although there was not a statistically significant difference (1330±1282 vs 1040±1270, respectively; P >.05).

The researchers observed bilateral hearing loss in 28 of the 48 individuals with hearing loss. They found pure conductive hearing loss in 29 individuals, pure sensorineural hearing loss in 3, and a combination of sensory and conductive hearing loss in 16. The majority of hearing loss was mild (n = 38) compared to moderate to severe (n = 10). Although disease severity did not correlate with hearing loss, old age did (P ≤.05). The majority (70%) of individuals experienced low-frequency conductive hearing loss at 0.25, 0.5, and 1 kHz whereas 75% individuals with sensorineural hearing loss experienced it at high frequencies of 4 and 8 kHz.

Limitations to this study include the use of recall and available prescriptions to note intake of NSAIDs, as well as not considering hypertension as a hearing loss risk factor.

“Hearing loss is common in patients with AS and is usually mild,” the study researchers concluded. “While previous studies have reported [sensorineural hearing loss] as the predominant type, we found low frequency conductive [hearing loss] to be more common. Additional studies are required to look at the joint and ligament involvement in the middle ear in patients with AS.”

Reference

Ajmani S, Keshri A, Srivastava R, Aggarwal A, Lawrence A. Hearing loss in ankylosing spondylitis [published online May 6, 2019]. Int J Rheum Dis. doi:10.1111/1756-185X.13560