Cochlear implants for children and adults with severe to profound deafness

4.1 Clinical effectiveness

4.1.1 The assessment group identified studies of cochlear implants that included adults and/or children with severe to profound deafness. The assessment group included only studies of multichannel cochlear implants that used whole-speech processing coding strategies, because these most closely represent the type of device available to the NHS. The assessment group included randomised and non-randomised controlled trials, including studies in which participants acted as their own controls. [2009]

4.1.2 The systematic review by the assessment group comprised 33 studies, of which 13 involved adults and 20 involved children. Meta-analysis of the data was not possible because of heterogeneity between the studies. Only 2 implant systems in the NHS contract (both supplied by Cochlear Europe) were represented in studies included in the systematic review. Three companies – Advanced Bionics UK, Cochlear Europe and MED-EL UK – submitted additional studies reporting the clinical effectiveness of their implant systems. Neurelec did not submit evidence of clinical effectiveness to this appraisal. [2009]

4.2 Cost effectiveness

4.2.1 Submissions were received from 3 companies. Two (Cochlear Europe, Advanced Bionics UK) provided de novo economic evaluations. The third (MED-EL UK) provided a narrative summary of existing published economic analyses. The assessment group identified a total of 9 studies that reported cost effectiveness or cost–benefit ratios from the perspective of the NHS. These reported incremental cost-effectiveness ratios (ICERs) for unilateral cochlear implantation ranging from £2,000 to £20,000 per quality-adjusted life year (QALY) gained for children and £11,000 to £18,000 per QALY gained for adults. In addition, the assessment group carried out a de novo economic evaluation. [2009]

4.3 Consideration of the evidence

4.3.1 The appraisal committee reviewed the data available on the clinical and cost effectiveness of cochlear implants for children and adults with severe to profound deafness, having considered evidence on the nature of the condition and the value placed on the benefits of cochlear implants by people who are deaf, those who represent them, and clinical experts. It was also mindful of the need to take account of the effective use of NHS resources. [2009]

4.3.2 The committee considered the distinction between audiological and functional deafness. The committee heard from clinical experts that audiological hearing was not necessarily related to functional hearing. Therefore, in clinical practice a person's hearing is assessed not just by audiological tests, but also by a functional test of hearing, specifically their ability to perceive speech in quiet conditions with acoustic hearing aids. The committee concluded that decisions about the appropriateness of cochlear implants should take into consideration a person's functional hearing and the benefit they gain from acoustic hearing aids. [2009]

4.3.3 The committee considered how functional deafness could be defined in clinical practice. At the time of the original appraisal it heard from clinical experts that guidelines for adults from the British Cochlear Implant Group recommend Bamford-Kowal-Bench (BKB) sentence testing. Using this approach, an adequate benefit from hearing aids is defined as a score of 50% or greater at a sound intensity of 70 dB SPL. But after a review of the guidance in 2018 stakeholders agreed that the test and the criteria were out of date and the committee agreed to update recommendation 1.5 (see section 4.4). The committee heard that tests for children should assess whether speech, language and listening skills are appropriate to the age, development stage and cognitive ability of the child. The committee heard that the most appropriate test would differ according to the age and developmental stage of the child. The committee considered that the BKB sentences may not be appropriate for assessing hearing in adults for whom English is a second language, and for adults with other linguistic or cognitive difficulties. The committee considered that those making the hearing assessments should take these factors into account. In these situations, modification of the testing procedure or alternative tests may be required. [2009]

4.3.4 The committee recognised that identifying people for whom cochlear implantation was appropriate took account of not only the results of audiological and functional hearing tests but also other factors such as fitness for surgery, structure of the cochlea, the presence of functioning auditory nerves and the likelihood of benefiting from the stimuli produced by the device. The committee heard from clinical experts that these factors were assessed as part of a multidisciplinary assessment, which would also include a trial of acoustic hearing aids that usually lasts for 3 months, if this was not contraindicated or inappropriate. The committee concluded that it was essential to determine the appropriateness of cochlear implantation through a multidisciplinary assessment, with input from a range of professionals involved in the care of children and adults with cochlear implants. This was in addition to audiological and functional hearing tests and a valid trial of acoustic hearing aids that usually lasted 3 months. [2009]

4.3.5 The committee considered the perspective of people who may not consider deafness a disability that needs to be treated. The committee heard from clinical experts that most children who are deaf have families who are hearing and who have no access to Deaf culture. In addition, it is unlikely that adults who become deaf will become proficient users of sign language and integrate into the Deaf community. The committee concluded that for many people deafness would have a significant adverse impact on their quality of life, and that it was appropriate to consider cochlear implants as a means of reducing this impact. [2009]

4.3.6 The committee noted that the evidence for clinical and cost effectiveness was derived from data based on cochlear implant systems from 3 companies making cochlear implants (Advanced Bionics UK, Cochlear Europe, MED-EL UK), and that no data for clinical effectiveness were identified for cochlear implant systems from the fourth company (Neurelec). The committee was aware that cochlear implant systems from Neurelec are included in the current NHS procurement contract, but heard from clinical experts that Neurelec implants are rarely used in the NHS. The committee concluded that it was only able to issue recommendations about the devices for which there was evidence available. [2009]

4.3.7 The committee examined the evidence for the clinical effectiveness of the use of unilateral cochlear implants for adults and children with severe to profound deafness. The committee considered that, despite methodological limitations, the studies showed benefits for providing unilateral cochlear implants compared with hearing aids or non-technological support for people who were appropriately assessed. The committee concluded that unilateral cochlear implants had been shown to be clinically effective. [2009]

4.3.8 The committee examined the evidence for the cost effectiveness of unilateral cochlear implantation. The committee noted that both the assessment group and the companies obtained similar estimates of cost effectiveness. The committee considered that the analyses of cost effectiveness for unilateral implantation were a reasonable reflection of the costs and benefits. The committee concluded that unilateral cochlear implantation for adults and children with severe to profound deafness who did not derive adequate benefit from acoustic hearing aids would be a cost-effective use of NHS resources. [2009]

4.3.9 The committee considered the evidence for the clinical effectiveness of bilateral cochlear implants. The committee considered that the additional benefits of bilateral cochlear implantation were less certain than the benefits of unilateral cochlear implantation. This was because of the limitations of the evidence base owing to the small number of studies and the small numbers of participants. However, the committee considered that the studies had shown additional benefits to having a second cochlear implant in relation to speech perception in noisy situations and directional perception of sound. The committee heard from patient experts that they considered that there were other benefits from bilateral cochlear implantation. These benefits included easier, less exhausting communication (for example, determining the direction of the sound in group conversations without unnecessary head movement). The committee concluded that there were additional benefits of bilateral cochlear implants that had not been adequately evaluated in the published studies, although these may vary among individuals. [2009]

4.3.10 The committee heard from clinical experts that it was important that the auditory nerve was provided with stimulation early in a child's development because it became less sensitive to stimulation as the child became older. Hence, failure to stimulate the auditory nerve early impaired the development of central pathways necessary for the appreciation and understanding of sound. The committee was persuaded on the basis of consultee comments that the potential benefits of bilateral auditory stimulation would apply to both prelingual and postlingual children with severe to profound deafness because neurosensory development continues after the development of language. The committee concluded that making a distinction between children based on the time of language development would not be appropriate. [2009]

4.3.11 The committee then considered the cost effectiveness of bilateral cochlear implantation. The committee first examined the cost of cochlear implant systems and in particular the availability of nationally agreed discounts for the second cochlear implant system. The committee noted that the current NHS supply chain contract only included 1 discount on a bilateral system from a single company (Neurelec). The committee then considered the information about discounts provided by the other 3 companies. The committee noted that 2 of the 3 companies reported their discounts as being standardised and nationally available. The committee recognised that these discounts were sometimes given on the implant alone and other times on the whole implant system (that is implant plus processor), and that this would affect the total cost of the system. The committee examined the information on discounts from the survey of cochlear implant centres (described in section 3.7). The committee noted that there was some variation in the size of the discount received by the cochlear implant centres that was not reflected in the information from the companies. The committee noted this did not appear to relate directly to volume of implants purchased. The committee considered that the data showed that discounts of 40% or more on the second implant were being attained by a large proportion of implant centres, and therefore could be considered as being available nationally. Therefore the committee concluded that it was appropriate for this size of discount to be taken into account when considering the estimates of incremental cost effectiveness of bilateral implantation. [2009]

4.3.12 The committee then considered the cost effectiveness of bilateral cochlear implantation in adults. The committee noted that the base-case economic analyses provided by the assessment group obtained an ICER for simultaneous bilateral cochlear implantation of approximately £50,000 per QALY gained. The committee noted that the utility data used in this analysis were associated with uncertainty because the data were derived from a small number of adults over a short follow-up period. However, the committee noted that these were the only data available for people who had been studied prospectively before and after they had received a second cochlear implant. Therefore the committee considered that this was the most appropriate source of data for estimating health utility gain following a second implant. The committee noted concerns from consultees about the impact of tinnitus on the utility results from this study. It accepted the analysis of the study data that had controlled for the impact of tinnitus and gave a health utility gain following a second implant of 0.03. Therefore the committee considered that 0.03 was currently the most appropriate estimate of the additional utility gain for a second implant for adults with severe to profound deafness. The committee noted the assessment group's assumption of no discount for the second implant in their base-case analysis. The committee considered the situation of a 25% to 50% discount on the second implant system as discussed in section 4.2.17. Under these circumstances the ICER for bilateral implantation for adults was between £43,000 and £36,500. The committee noted from the assessment group's analysis that with a utility gain of 0.03, discounts on the second implant system had to be greater than 75% for the ICER for bilateral implantation in adults to fall between £20,000 and £30,000 per QALY gained. Therefore the committee concluded that it was not possible to recommend routine bilateral cochlear implantation in adults as a cost-effective use of NHS resources. [2009]

4.3.13 The committee next examined the evidence for the cost effectiveness of bilateral cochlear implantation for children with severe to profound deafness. The committee noted that the assessment group had been unable to identify any health-related quality-of-life data for bilateral cochlear implantation in children, and had used the data from adults for children (that is, an additional gain in health-related utility of 0.03 for the second implant). The committee noted comments from consultees that for children with severe to profound deafness, a utility gain of 0.03 could potentially be an underestimate. These comments focused on the view that bilateral cochlear implantation could afford more quality-of-life gains for children than for adults, through improved language learning and spatial awareness, which would increase opportunities for interaction and communication, the ability to participate in play activities, and benefits from education. The committee was persuaded that additional utility gains for children above that for adults were plausible. However, the size of these additional gains was associated with considerable uncertainty, given that there were limited data for children, and for adults the additional gains in health-related quality of life were associated with methodological concerns. The committee recognised that the economic analyses were sensitive to utility gains, and that if the gain in utility for children was assumed to be more than for adults, the ICER for bilateral cochlear implantation would be considerably reduced from the base case. [2009]

4.3.14 The committee then considered the impact on the ICERs of combining additional gains in utility for simultaneous bilateral cochlear implantation of children with discounts on the second implant. The committee noted that the 40% discount for the second cochlear implant for simultaneous bilateral implantation, which was being received by many cochlear implant centres, equated to approximately 30% off the cochlear implant system (implant plus processor). The committee noted that with a discount of 30% on the implant system and a utility gain of 0.04, the ICER for children would be £27,900 per QALY gained. If the same discount was applied and the utility gain was assumed to be 0.05, then the ICER for children would be £22,700 per QALY gained. The committee was mindful that the size of the additional utility gain following simultaneous bilateral implantation for children was very uncertain, but was persuaded that with the discounts on second implants currently available, it could accept the uncertainty associated with the gains in utility. Therefore the committee concluded that if cochlear implants for bilateral implantation could be acquired at the lowest price, including a discount equivalent to 40% or more off the current list prices of the second implant, then simultaneous bilateral cochlear implantation for appropriately assessed children with severe to profound deafness could be considered a cost-effective use of NHS resources. [2009]

4.3.15 The committee recognised that some people who were deaf could also be at risk of ossification of the cochlea (for example, after meningitis). The committee heard from clinical experts that ossification caused damage to the cochlea, which could make both initial implantation and successful re-implantation in the case of device failure difficult. The committee noted that the incidence of ossification after meningitis is unclear. However, it understood that a minority of people at risk of cochlear ossification went on to have cochlear ossification, and that the extent of the ossification varied. The committee noted the evidence that, in general, device failure rates after successful implantation were low (less than 5% over 15 years), and considered that the probability of cochlear ossification occurring in adults with severe to profound deafness combined with failure of the unilateral implant and an inability to re-implant the first ear was therefore likely to be very small. On balance the committee considered that this very low risk was not in itself a reason to recommend bilateral implantation in this group when for adults overall it had not considered this a cost-effective use of NHS resources. [2009]

4.3.16 The committee recognised that there were additional considerations for people who are deaf and also have other disabilities. The committee heard from clinical experts that specifically for people who are both deaf and blind, the gains in quality of life following bilateral implantation are greater than for people who are not blind. This is because people who are deaf and blind rely more on auditory stimuli for spatial awareness. The committee recognised that in addition to people who are deaf and blind, there are people with other co-disabilities who also rely on auditory stimuli as a primary sensory mechanism for spatial awareness. The committee considered that these individuals would be most appropriately identified by healthcare professionals as part of a multidisciplinary assessment. The committee was persuaded by the evidence from clinical experts that bilateral cochlear implantation did produce greater quality-of-life gains for deaf people who are blind or have other co-disabilities that increase reliance on hearing as a primary sensory mechanism for spatial awareness than it did for people who are deaf and who do not have other disabilities of this nature. The committee agreed that the inclusion of discounts equivalent to 40% or more off the list prices of the second implant was appropriate in the cost-effectiveness analyses, as these reflected current nationally available discounts. The committee was mindful of the uncertainty over the magnitude of the additional quality of life gains associated with bilateral cochlear implantation in this group of people, but was persuaded that using the currently available discounts would result in an acceptable cost-effectiveness estimate. Therefore the committee was persuaded that if cochlear implants for bilateral implantation were acquired at the lowest price, including currently available discounts on list prices equivalent to 40% or more off the second implant, then it was appropriate to recommend bilateral cochlear implantation in this group of people as a cost-effective use of NHS resources. [2009]

4.3.17 The committee noted that sequential implantation was associated with higher cost-effectiveness estimates than simultaneous bilateral implantation for both children and adults, and therefore concluded that sequential bilateral implantation is not an appropriate use of NHS resources. However, the committee recognised that some children who have previously received unilateral implants may now be considered to have met the criteria in the current guidance for simultaneous bilateral implantation. Similarly, this is the case for adults who are deaf and have other disabilities that increase their reliance on auditory stimuli as a primary sensory mechanism for spatial awareness. The committee considered that it is important to promote equity of treatment between groups of people who are in the same circumstances except that one group had previously had a unilateral cochlear implant and the other becomes eligible now. However, the committee was mindful that the duration of deafness and length of time since unilateral implantation could reduce the benefits of any additional contralateral cochlear implant. The committee was persuaded that in situations where the responsible clinician considers that an additional contralateral cochlear implant would provide sufficient benefit, people in the above 2 groups who have already received a unilateral cochlear implant prior to publication of this guidance should have the option of an additional contralateral implant. However, the committee considered that an additional implant should be offered only after a fully informed discussion between the individual person, their carers and clinicians involved in their care. [2009]

4.3.18 The committee noted that in the economic analyses cochlear implants had been modelled as a class. The committee was aware from clinical experts that there may be differences between the devices, in particular the processing strategies used. The committee did not consider that it had been demonstrated that the different cochlear implant systems were associated with different cost-effectiveness profiles. Therefore it was not appropriate to preferentially recommend a specific device. However, the committee did consider that if there was more than one cochlear implant system that was considered clinically appropriate, the least costly implant system, taking into account discounts as available, should be used. The committee recognised that the cost of a system would depend on the support package offered, the long-term reliability of the device and whether it was to be used unilaterally or bilaterally. [2009]

4.4 Partial update

4.4.1 In 2018, as part of a review of this guidance, stakeholders highlighted that the eligibility criteria in recommendation 1.5 were out of date and did not reflect clinical practice.

4.4.2 Changing the criteria in section 1.5 of the guidance is not expected to have a substantial impact on the cost effectiveness of cochlear implants. This is because:

4.4.3 The committee considered that the wording suggested by stakeholders was appropriate and would not have a substantial impact on the cost effectiveness of cochlear implants. It concluded that the criteria in section 1.5 of the guidance should be updated to:

For the purposes of this guidance, severe to profound deafness is defined as hearing only sounds that are louder than 80 dB HL (pure-tone audiometric threshold equal to or greater than 80 dB HL) at 2 or more frequencies (500 Hz, 1,000 Hz, 2,000 Hz and 4,000 Hz) bilaterally without acoustic hearing aids. Adequate benefit from acoustic hearing aids is defined for this guidance as: