High cumulative antibiotic dosing tied to hearing loss in cystic fibrosis
High cumulative dosing of intravenous aminoglycoside (IV-AG) antibiotics for cystic fibrosis (CF) was associated with an increased risk of hearing loss, a recent study found.
“This suggests that ongoing clinical monitoring of cumulative lifetime IV-AG dosing in patients with CF is needed,” said the researchers. “The data also provide strong evidence for routine hearing evaluations with extended high-frequency testing (9.0–16.0 kHz) on every CF patient who has or will receive IV-AG treatments in their lifetime.”
Among the 81 participants who underwent hearing test, 45 (56 percent) had sensorineural hearing loss (SNHL), defined in the study as >25 dB hearing loss at one or more frequencies between 0.25–16.0 kHz, in one or both ears. [J Cyst Fibros 2017;doi:10.1016/j.jcf.2017.01.006]
Participants at the highest quartile of cumulative lifetime dosing of IV-AGs (152–647 mg/kg/day) were 4.53 times more likely to have SNHL than those at the lowest quartile (2–15 mg/kg/day) (95 percent confidence interval [CI], 1.03–20.02), even after accounting for age and gender.
After combining the highest two cumulative dosing quartiles (57–647 mg/kg/day), the participants saw 4.79 times higher odds (p=0.005) of developing SNHL when compared with the lowest two cumulative dosing quartiles combined (2–52 mg/kg/day).
Compared with participants with normal hearing, those with SNHL were significantly older (median age 21 vs 26 years). For every 1-year increase in age, there was a 1.16 increased odds of developing SNHL (95 percent CI, 1.06–1.26; p=0.001).
“The diversity of hearing thresholds in each quartile suggests that using cumulative dosing exclusively to determine who should be screened for hearing loss is inadequate, but, may be used to identify participants at higher risk for hearing loss,” said the researchers, who suggested that other factors such as renal function and inflammation might contribute to the variability of hearing loss development in each quartile.
“This information will allow both the patient and the physician to discuss possible modifications to the treatment regimen, particularly if an alternative approach is or becomes available, or at a minimum provides a basis for recommendation for rehabilitation,” they added.
As the hearing status of the participants were estimated through a single hearing test, the researchers noted that repeated testing after treatment might have improved the estimates, although this was unlikely to affect the current findings.
“It is recommended that clinics monitor patients for early changes in hearing function, particularly at higher frequencies, pre- and post IV-AG treatments. This allows for identification of hearing damage before it reaches frequencies important for speech discrimination (eg, 0.5–8.0 kHz)… and refer patients for immediate audiological monitoring,” suggested the researchers.