Non-use of cochlear implants by post-lingually deafened adults.
OBJECTIVE
To document the occurrence of medical/surgical complications in the provision of cochlear implants to a cohort of post-lingually deafened adult patients; to compare cumulative mortality in the cohort with cumulative mortality predicted from an aged-matched control population; to relate the occurrence of medical/surgical complications to the patient's position in the case series; to identify risk factors for elective non-use of implants; and to examine the impact of complications, mortality and elective non-use on the cost of creating a successful user of a cochlear implant.


METHODS
Longitudinal prospective observational study.


METHODS
Nine hospitals in the UK, which received central funding between 1990 and 1994 to participate in a programme of adult implantation.


METHODS
All 313 post-lingually deafened adults who received multichannel cochlear implants in this programme.


METHODS
Status of patients in July 1998 (dead, an elective non-user or a user); duration of use prior to death or elective non-use; costs of creating and sustaining a successful user; ability to identify environmental sounds; self-reported benefit.


RESULTS
Cumulative mortality after 7.5 years was 6.3% (95% CI 2.5-10.1%) and was no different from cumulative mortality predicted from life expectancy in the general population. Cumulative elective non-use was stable at 6.3% (95% CI 3.6%-9.1%) between 4 and 7 years after implantation but rose to 11.0% (95% CI 1.7%-20.3%) at 7.5 years after implantation. Major medical/surgical complications were experienced by 25/313 patients (8.0%). The occurrence of such complications declined to ca. 1% over the first 50 cases in a hospital's case series. For patients who were users, self-reported benefit did not differ between patients who had experienced complications and those who had not. Older age at implantation, greater duration of deafness prior to implantation or an early position in a hospital's case series were not significant risk factors for elective non-use. Experiencing a major complication was a marginally significant risk factor (odds ratio = 3.2, 95% CI 1.0-10.6). Low auditory performance (odds ratio = 8.2, 95% CI 2.1-31.9) and low self-reported benefit (odds ratio = 19.6, 95% CI 4.6-84.4) were significant risk factors. Medical/surgical complications raised the cost of creating a successful user by less than 1%. Elective non-use raised the cost by between 5% and 10%.


CONCLUSIONS
Medical/surgical complications were generally managed successfully without detriment to benefit; life expectancy in the general population can be used to predict the length of time for which patients have the potential to use cochlear implants; patients who experience little benefit are most at risk for elective non-use; given the high cost of cochlear implantation, benefit should be monitored to allow early rehabilitative intervention in cases of low benefit; patient cohorts such as the present one should continue to be followed up with a view to identifying pre-operative risk factors for elective non-use.
Summerfield
A Q
AQ
MRC Institute of Hearing Research, University Park, Nottingham NG7 2RD, UK. aqs@ihr.mrc.ac.uk
Marshall
D H
DH