Injection therapy for sudden hearing loss disorder may be suitable alternative to oral steroids

Idiopathic (unknown cause) sudden sensorineural (involving the sensory nerves) hearing loss, a hearing loss with onset in less than 72 hours, has an estimated incidence between 5 and 20 per 100,000 persons per year, although this is likely to be an underestimate because many who recover quickly never seek medical attention. The current standard treatment for idiopathic hearing loss has been a course of oral corticosteroid (prednisone or methylprednisolone), according to background information in the article.

In recent years, intratympanic (within the drum of the ear) corticosteroid treatment by direct injection into the middle ear has gained wide popularity. One theoretical advantage of intratympanic treatment is an increased drug concentration in the targeted area, with reduced systemic steroid exposure and associated systemic adverse effects that may accompany oral steroids. "However, no adequately powered prospective randomized controlled trial has compared oral and intratympanic steroid treatments to demonstrate that increased local drug concentration leads to improved hearing outcome," the authors write.

Steven D. Rauch, M.D., of Harvard Medical School, Boston, and colleagues conducted a multicenter, randomized, noninferiority (outcome not worse than treatment compared to) trial comparing the efficacy of oral prednisone to intratympanic methylprednisolone for primary treatment of idiopathic hearing loss. Noninferiority was defined as less than a 10-dB difference in hearing outcome between treatments. The study included 250 patients with unilateral sensorineural hearing loss who presented for care within 14 days of onset of hearing loss of 50 dB or higher of pure tone average hearing threshold. Pure tone average (PTA) was calculated as the arithmetic average of the hearing thresholds at 500,1000, 2000, and 4000 Hz in the affected ear. The study was conducted from December 2004 through October 2009 at 16 academic community-based otology practices. Participants were followed up for 6 months. One hundred twenty-one patients received 60 mg/d of oral prednisone for 14 days with a 5-day taper and 129 patients received 4 doses over 14 days of 40 mg/mL of methylprednisolone injected into the middle ear.

The researchers found that improvement in PTA at 2 months in the intratympanic methylprednisolone group was not in­ferior to PTA improvement in the oral prednisone group. "In the oral prednisone group, PTA improved 30.7 dB compared with 28.7 dB in the intratympanic group. Pure tone average at 2 months averaged 56.0 dB for the oral group and 57.6 dB for the intratympanic group. The point estimate of the difference between the oral and intratympanic groups in the [average] change in PTA from baseline to 2 months after randomization is 2.0 dB," the researchers write.

Further comparison of hearing recovery in the oral and intratympanic treatment groups also showed that the 2 treatments were comparable at 2 and 6 months. The frequency of hearing recovery to normal was 20.7 percent; to hearing aid range, 66.9 percent in the oral treatment group vs. 24.8 percent and 62.0 percent in the intratympanic group, respectively.

"Overall, intratympanic methylprednisolone was shown to be not inferior to oral prednisone for treatment of idiopathic sudden sensorineural hearing loss. Noninferiority was also indicated for certain subgroups. Both oral and intratympanic treatments are safe but can cause unpleasant adverse effects. The comfort, cost, and convenience of oral prednisone are better than intratympanic treatment. Intratympanic treatment is a suitable alternative if there are medical contraindications to oral prednisone," the authors write.

The researchers add that there are a number of hearing loss treatment questions that remain unanswered by this study. "In future analyses, we hope to explore our data for possible predictors of treatment outcome. Although we observed similar efficacy of oral and intratympanic treatments overall, our subgroup analyses suggested that certain subgroups might achieve greater benefit from one treatment than the other."

Editorial: Steroids for Idiopathic Sudden Sensorineural Hearing Loss -- Some Questions Answered, Others Remain

The findings of this study provide a new therapeutic option for patients with sudden hearing loss for whom oral steroids are contraindicated, writes Jay F. Piccirillo, M.D., of the Washington University School of Medicine, St. Louis, in an accompanying editorial.

"The use of intratympanic steroids is moderately uncomfortable, inconvenient, and more costly than oral steroids and is associated with several relatively minor adverse effects. Nevertheless, for patients with sudden hearing loss who are thought to be at too high a risk for systemic steroid usage, this study suggests a reasonable alternative in the setting of rapid specialty referral. Additional research should focus on identifying subgroups of patients for whom steroid treatment seems especially helpful and whether combination oral and intratympanic is better than single modality alone. However, the study by Rauch et al did not answer the lingering question of whether there is any benefit of steroids for the patient with sudden sensorineural hearing loss. A better understanding of the pathophysiology of hearing loss, identification of unique prognostic subgroups, and adherence to rigorous clinical research methods are required for the proper assessment of the therapeutic benefits of existing treatments and discovery of new treatments for this disorder."