Symptom Reporting Compared with Audiometry for the Detection of Cochleotoxicity in Patients on Long-Term Aminoglycoside Therapy

Abstract

BACKGROUND: Aminoglycoside-associated auditory toxicity (cochleotoxicity) is a major concern in patients receiving prolonged aminoglycoside therapy. There are no published data comparing symptom monitoring to audiometry testing for the detection of aminoglycoside-induced cochleotoxicity; thus, agreement regarding the optimal monitoring of these patients for early detection of this effect is lacking. OBJECTIVE: To compare the sensitivity of symptom monitoring to that of audiometry in identifying cochleotoxicity in patients on prolonged aminoglycoside therapy. METHODS: A retrospective chart review of adult inpatients at Sunnybrook Health Sciences Centre prescribed prolonged aminoglycoside therapy (≥21 days) who completed at least 1 audiometry test between January 1, 1999, and December 31, 2009, was conducted. Data pertaining to results of audiometry testing and development of symptoms of auditory toxicity were collected. Symptom monitoring was compared with audiology testing for the detection of cochleotoxicity. RESULTS: Forty eligible patients were included for analysis. Audiometry was significantly better than symptom monitoring to identify early cochleotoxicity (absolute risk reduction = 17.5% and number needed to treat = 6; p = 0.023). Compared to audiometry, symptom monitoring has a sensitivity, negative predictive value, and accuracy for the detection of early cochleotoxicity of 61%, 75%, and 82%, respectively. CONCLUSIONS: Audiometry testing is significantly better than monitoring symptoms to identify early aminoglycoside-induced auditory toxicity in patients prescribed prolonged aminoglycoside therapy (≥21 days). Subclinical cochleotoxicity identified with audiometry may allow early termination of aminoglycoside therapy to prevent progression of cochlear damage to the audible frequency range.