Criteria of candidacy for unilateral cochlear implantation in postlingually deafened adults II: cost-effectiveness analysis.

OBJECTIVES: The objectives of this study were to estimate the cost-effectiveness of unilateral cochlear implantation for postlingually deafened adults; to study the impact on cost-effectiveness of relaxing criteria of candidacy to include patients who benefit from acoustic hearing aids; and to study the further impact of age at implantation and duration of profound deafness before implantation.
DESIGN: This prospective cohort study was carried out in 13 hospitals with four groups of severely to profoundly hearing-impaired subjects distinguished by their preoperative ability to identify words in prerecorded sentences when aided acoustically. The groups represent a progressive relaxation of criteria of candidacy: Group I (N=134) scored 0% correct without lipreading and did not improve their lipreading score significantly when aided; group II (N=93) scored 0% without lipreading but did improve their lipreading score significantly when aided; group III (N=53) scored 0% without lipreading when the ear to be given an implant was aided but between 1% and approximately 50% when the other ear was aided; and group IV (N=31) scored between 1% and approximately 50% without lipreading when the ear to be given an implant was aided. Lifetime costs to the UK National Health Service of providing and maintaining a cochlear implant were estimated for each subject. The gain in health utility from cochlear implantation was estimated with the Mark III Health Utilities Index and was combined with life expectancy to estimate the number of quality-adjusted life-years (QALYs) that would be gained from cochlear implantation. Cost/QALY ratios were calculated by means of the Net Benefit technique and were compared with an upper limit of acceptability of 50,000 euros/QALY.
RESULTS: Averaged over the whole cohort, the cost of gaining a QALY was 27,142 euros (95% confidence interval, 24,532 euros to 30,323 euros); 203 of 311 (67%) of the cohort displayed cost/QALY ratios more favorable than 50,000 euros/QALY. The average cost of gaining a QALY increased from group I (24,032 euros) to groups II (27,062 euros) and IV (27,092 euros) to group III (39,009 euros). Cost/QALY varied with age at implantation from 19,223 euros for subjects who were younger than 30 yr of age to 45,411 euros for subjects who were older than 70 yr of age. Cost/QALY was unacceptable because of minimal gain in health utility for the subset of groups I and II, who were given implants in ears that had been profoundly deaf for more then 40 yr and for the subset of groups III and IV, who were given implants in ears that had been profoundly deaf for more than 30 yr.
CONCLUSIONS: Cochlear implantation was a cost-effective intervention for the majority of subjects, including the group given implants when older than 70 yr of age. Relaxation of criteria of candidacy for cochlear implantation reduces cost-effectiveness. Prioritization of the provision of cochlear implantation should take duration of profound deafness in the ear to be given an implant into account, as well as preoperative word recognition performance.