Background Cystic fibrosis (CF) patients are at high risk of aminoglycoside ototoxicity, causing hearing loss, tinnitus or balance problems which can have significant social and psychological implications. The incidence of aminoglycoside cochlear ototoxicity in CF patients is unclear but incidences up to 21% in children have been quoted. Early detection of ototoxicity may lead to prevention of further damage by modifying or stopping the aminoglycoside treatment.
Aim The study aimed to establish the current aminoglycoside use and monitoring in all specialised CF units in the UK and compare them to the previous survey results done by Tan et al. in 2002. This study only considered cochlear ototoxicity i.e. hearing loss.
Method A survey was sent to all CF units in the UK. The questions included demographics, choice of aminoglycosides, aminoglycoside regimen, ototoxicity monitoring and screening for m.1555A >G mutation.
Results Responses were obtained from 33 out of the 48 CF units (69%) across the UK. Responses were received from all parts of the UK but mostly south of England. The most commonly used aminoglycoside for treatment of acute pulmonary exacerbations in CF was intravenous tobramycin. Extended interval dosing (once or twice a day) was used in 97% of responding units. Ototoxicity monitoring was undertaken in 79% (23/29) of the responding units. Only 1/21 units (5%) monitored all patients regardless of symptom presence and 5/21 units (24%) provided the monitoring annually. Extended range high frequency audiometry was used only in 5/22 units (23%) as part of the ototoxicity monitoring testing. Standard pure tone audiometry was used in 19/23 units (86%).
Conclusion Numbers of CF units providing ototoxicity monitoring has substantially improved since 2002 (13% to 79%) but there is a wide variability in the indications, frequency and tests used. A significant improvement of the use of extended interval antibiotic dosing since 2002 (35% to 97%) has occured, reflecting the UK Cystic Fibrosis Trust (2009) recommendations. Standardised recommendations for ototoxicity monitoring are required to reduce the variability in its provision and improve patient care. This is particularly important because the life expectancy of CF patients is increasing.