June 19, 2007
The validity of steroid treatment in cases of sudden hearing loss has been called into question by a newly published study that labels original research that established the treatment’s popularity, “severely limited.”
"Systemic steroids cannot be considered the gold standard of treatment of sudden sensorineural hearing loss, given the severe limitations of the landmark study supporting their use," the new report’s authors state. Anne Elizabeth Conlin, BA & Sc, MD, of the University of Ottawa, Ontario, and Lorne S. Parnes, MD, FRCSC, of the University of Western Ontario, London, Canada, authored the study which states: "To our knowledge, no valid randomized controlled trial exists to determine effective treatment of sudden sensorineural hearing loss."
In a systematic review and meta-analysis, both published in the June issue of Archives of Otolaryngology-Head & Neck Surgery, Conlin and Parnes scrutinize the earlier studies that supported steroid treatment, which the authors point out is not described as a randomized trial and possibly yielded exaggerated treatment effects.
The authors suggest that this study also used inconsistent doses of steroids and did not measure outcomes at the same time for all participants. "The study therefore does not inform the otolaryngologist of what dose of steroids to use, nor at what time after treatment to expect improvement," the authors write.
For the systematic review, 21 trials were identified and evaluated, all of which used measures from hearing tests to define treatment outcomes. "Only two studies used identical criteria to define sudden sensorineural hearing loss," the authors write. "The method of randomization was described in two studies. Validity scores ranged from two to eight (of nine). Positive results were reported favoring systemic steroids, intratympanic [inside the inner ear] steroids, batroxobin, magnesium, vitamin E and hyperbaric oxygen, although there were serious limitations in each study with a positive finding."
For the meta-analysis, data from the same trials were combined when they covered the same therapies. Five trials were eligible for the analysis. "Pooling of data from two randomized clinical trials that compared steroids with placebo showed no difference between treatment groups," the authors write. "No difference existed between patients treated with antiviral plus steroid therapy vs. placebo plus steroid therapy. Finally, there was no difference between subjects treated with steroids vs. subjects treated with any other active treatment."
Treating sudden hearing loss is difficult because its cause is often unknown, the authors note. However, it is still important to identify the therapy that most benefits the patient. "At present, sudden sensorineural hearing loss remains a medical emergency without a scientific understanding of its cause or a rational approach to its treatment," they conclude.