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National Guideline Centre (UK). Hearing loss in adults: assessment and management. London: National Institute for Health and Care Excellence (UK); 2018 Jun. (NICE Guideline, No. 98.)

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Hearing loss in adults: assessment and management.

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15Hearing aids

15.1. Introduction

Hearing loss affects a large portion of the general population. In the majority of cases, hearing loss in adults affects both ears and is permanent. The primary management option for permanent hearing loss is hearing aids. All hearing aids consist of a microphone, an amplifier powered by a battery, a receiver, and a means to route the amplified sound into the ear canal.

The general goal of prescribing and fitting hearing aids is to improve functional auditory capacity and restore good communication skills and participation in everyday life. Hearing aids partially overcome the deficits associated with hearing loss by restoring the audibility of sound and improving the intelligibility of speech. Because hearing aids cannot improve deficits in frequency, temporal resolution and spatial resolution that generally accompany the most common causes of permanent hearing loss, an adult with hearing loss may continue to experience some difficulties, even when wearing hearing aids.

Prescribing and fitting hearing aids to both ears (bilateral fitting) has the potential to provide binaural stimulation. The benefits of binaural stimulation include improved intelligibility of speech in background noise, sound localisation, and sound quality. It also has the potential to avoid deficits that may develop over time if only 1 hearing aid is fitted and the unaided ear is deprived of stimulation. On the other hand, potential disadvantages of bilateral fitting include additional cost (to the NHS), a perception that 2 devices may be too complex for some people to use, and binaural interference (reduced speech intelligibility compared with performance with a single device). Quantifying the advantages and disadvantages of fitting 2 hearing aids is not straightforward. For this reason, it is not always clear who will benefit from (and accept) 2 hearings aids. Although the provision and fitting of bilateral hearing aids is considered the norm, this is based largely on theoretical benefits and efficacy studies in research laboratories. The intention of this chapter is to review the evidence on the clinical and cost effectiveness of providing hearing aids and to develop recommendations for their use in adults with hearing loss.

15.2. Review question: What is the clinical and cost effectiveness of hearing aids for mild to moderate hearing loss in adults who have been prescribed at least 1 hearing aid?

For full details see review protocol in appendix C.

Table 82. PICO characteristics of review question.

Table 82

PICO characteristics of review question.

15.2.1. Clinical evidence

A recent Cochrane review43 was identified that addressed our clinical question. The Cochrane review aimed to identify the clinical effectiveness of hearing aids versus no hearing aids for mild to moderate hearing loss. Five studies were included in the review.2,58,76,79,81 Two of these studies were deemed to be inappropriate for inclusion within the meta-analysis but otherwise met the review protocol and are summarised narratively below. It was not possible to include the Scaling Assessment reported by Melin 198779 in the meta-analysis as no usable data were reported for either the intervention or the comparator groups. However, the study reported a significant improvement for the hearing aid versus unaided comparator for the Scaling Assessment for easy to difficult hearing situations. In addition to this, the data on health-related quality of life reported by Adrait 20172 was not included in the meta-analysis due to the indirectness of the population, which was exclusively adults with Alzheimer’s disease. The committee agreed that this population was a distinctly different clinical population from typical first-time hearing aid users. However, this study was the only study that measured adverse effects and therefore was reported in the clinical evidence table.

The studies with data suitable for meta-analysis are summarised in Table 83 below. Evidence from these studies is summarised in the clinical evidence summary (Table 84). See also the study selection flow chart in appendix E, forest plots in appendix K, study evidence tables in appendix H, GRADE tables in appendix J and excluded studies list in appendix L.

Table 83. Summary of studies included in the review.

Table 83

Summary of studies included in the review.

Table 84. Clinical evidence summary: Hearing aids versus no hearing aids.

Table 84

Clinical evidence summary: Hearing aids versus no hearing aids.

The Cochrane review43 was incorporated into this guideline in the following ways:

  • Article selection and risk of bias assessment per study were directly adopted without further checking.
  • GRADE assessments for risk of bias, imprecision and inconsistency per outcome were checked. If differences with the standard methodology used within this guideline were found, GRADE ratings and subgroup analyses were amended accordingly to ensure consistency across the reviews within this guideline.

15.2.2. Economic evidence

15.2.2.1. Published literature

One health economic study was identified with the relevant comparison62 and has been included in this review along with the original health economic modelling conducted in appendix N. These are both summarised in the health economic evidence profile below (Table 85) and the former is summarised in a health economic evidence table in appendix I.

Table 85. Health economic evidence profile: hearing aids versus no hearing aids.

Table 85

Health economic evidence profile: hearing aids versus no hearing aids.

One health economic study relating to this review question was identified but was excluded due to the availability of more applicable evidence.15 This is listed in appendix M, with reasons for exclusion given.

See also the health economic study selection flow chart in appendix F.

15.2.2.2. Original cost-effectiveness analysis – summary

An original health economic model was constructed in order to conduct cost–utility analysis for this question and the review question regarding early versus delayed management of hearing loss (see chapter 8). These questions were agreed by the guideline committee to be the highest priorities for original economic analysis in this guideline due to the very large number of people using or potentially eligible for hearing aids, and the lack of existing health economic research in this area.

Full details of the analysis can be found in appendix N. It included a comparison between a cohort of people given a hearing assessment and offered hearing aids, if eligible, immediately after first presenting with hearing difficulties (early treatment) and a cohort who never undertook a hearing assessment and were never offered hearing aids (no treatment).

The base case probabilistic results, reflecting the costs and outcomes for men aged 65 at the start of the analysis over a lifetime horizon, are in Table 86.

Table 86. Results of hearing aids (early) versus no hearing aids, base case.

Table 86

Results of hearing aids (early) versus no hearing aids, base case.

Sensitivity analysis found these results to be robust to variations in all the parameters investigated in the analysis, including the age of the participants at the start of the analysis, their sex, the proportions not suitable for hearing aids or who decline to use hearing aids, rates at which participants stop using hearing aids, and the magnitude of improvement in quality of life caused by hearing aid use: the ICER was below £8,500 per QALY gained in every case.

15.2.3. Evidence statements

Clinical

  • There was a clinically important benefit of hearing aids for hearing-specific health-related quality of (HHIE; moderate quality evidence, 3 studies), overall health-related quality of life as measured by the WHO Disability Assessment Schedule II scale and the Self-evaluation of Life Function (moderate quality evidence, 2 studies), for overall listening ability as measured by the profile of hearing aid performance and the APHAB (moderate quality evidence, 2 studies).
  • There was no clinically important difference in health-related quality of life as measured by self-evaluation of life function (low quality evidence, 1 study).
  • No evidence was found comparing hearing aids to an active control (information or education only, listening tactics and communication training; assistive listening devices; or auditory training) or for the outcomes of pain or noise-induced hearing loss.

Economic

  • One cost–utility analysis found that hearing aids were cost effective compared with no hearing aids for managing hearing loss (ICER: £11,555 per QALY gained). This analysis was assessed as partially applicable with potentially serious limitations.
  • One original cost–utility analysis found that hearing aids were cost effective compared with no hearing aids for managing hearing loss (ICER: £4,167 per QALY gained). This analysis was assessed as directly applicable with minor limitations.

15.2.4. Recommendations and link to evidence

Recommendations
25.

Offer hearing aids to adults whose hearing loss affects their ability to communicate and hear, including awareness of warning sounds and the environment, and appreciation of music.

Relative values of different outcomesThe following outcomes were identified as critical outcomes for this review: hearing-specific health-related quality of life (key domain: participation) and the specific adverse event of pain. Important outcomes included health-related quality of life, listening ability and the specific adverse event of noise-induced hearing loss.
Quality of the clinical evidenceThe quality of the evidence was moderate for hearing-specific health-related quality of life and for health related quality of life and very low for the outcomes relating to adverse events (pain and noise induced hearing loss). All of the outcomes were downgraded for a high risk of bias. This was mainly due to a high risk of selection, performance or detection biases. These biases are widely acknowledged to be problematic within hearing aid intervention studies as the blinding of patients and outcome assessors can be difficult to achieve. 30,31 One of the studies had a follow-up period of 6 weeks but the committee agreed that the evidence should not be downgraded for indirectness as there is unlikely to be a significant clinical difference between a 6 week follow-up and an 8 week follow-up as specified in the protocol.
For the outcome of hearing-specific health-related quality of life where participation is the key domain, moderate quality evidence showed that hearing aids had a large beneficial effect in reducing participation restrictions. There were significant differences in the size of effects across studies. The effects reported by 2 studies in Veterans’ Administration settings were similar but more than twice the size of the effect reported by the third study which was set in a university hospital clinic. However, all 3 studies individually reported large beneficial effects that favoured hearing aids, meaning that while further evidence may change the size of the overall effect on hearing-specific health-related quality of life, there is high confidence in the magnitude and direction of the effect.
For the outcome of health-related quality of life as measured by the WHO Disability Assessment Schedule II (WHO-DAS II) scale 1 study showed a significant benefit of hearing aids compared with placebo or no hearing aids. Using the Self-evaluation of Life Function, another study found no significant beneficial effect of hearing aids. Overall, moderate quality evidence showed a small overall beneficial effect of hearing aids.
For listening ability, moderate quality evidence showed a large beneficial effect of hearing aids compared with unaided/placebo conditions based on 1 study that used the APHAB and another study that used the PHAP.
The planned subgroup analyses (age, sex, and degree of hearing loss) could not be performed as data from these subgroups were not reported.
No evidence was found comparing hearing aids to an active control (information or education only, listening tactics and communication training; assistive listening devices; or auditory training) or for the outcomes of pain or noise-induced hearing loss.
Trade-off between clinical benefits and harmsThe committee noted the limitations of the studies but agreed that the evidence demonstrated that people with mild to moderate hearing loss benefitted from having hearing aids as this improved their listening ability and quality of life. The committee acknowledged the difference hearing aids can make by enabling people to participate in everyday situations and the impact this can have in improving the quality of life for people with hearing difficulties.
The committee agreed that having hearing aids at an early stage of their hearing loss enables people to adjust more easily to using the aids. The committee is aware that people are often reluctant to seek help or are slow at identifying a difficulty. There is evidence that people have not been referred for further assessment when hearing loss is first suspected (see also chapter 8 on early versus delayed management of hearing loss).28
The committee noted that reporting for mild and moderate hearing loss had not been clearly separated in the studies.
Trade-off between net clinical effects and costsOne published economic evaluation was identified for this question. This measured the benefit to quality of life in 78 patients given hearing aid(s) for the first time and used this benefit in a lifetime model of hearing aid use. It found that hearing aid use was cost effective compared with no hearing aids at a cost-effectiveness threshold of £20,000 per QALY gained (ICER: £11,555 per QALY gained). However, the committee noted that the costs used in the study differed from current UK costs: in particular the cost used for hearing aids was much higher than UK costs. It also assumed a much longer time between replacement of hearing aids (at least 8 years), and a lower rate of fitting of 2 hearing aids (only 25%) than currently expected in the UK. Consequently the results of this analysis cannot be relied upon to relate to the current UK context.
The committee therefore also considered the relevance of the original economic modelling conducted for the early versus delayed management question in this guideline. By comparing both of the intervention arms (‘early’ and ‘delayed’) against the no treatment arm, the benefit of referring for assessment and, where suitable, prescribing and fitting hearing aids is demonstrated. This analysis showed that either early or delayed fitting of hearing aids would be highly cost effective compared with no treatment at the NICE cost-effectiveness threshold of £20,000 per QALY gained, with ICERs of £4,167 per QALY and £4,421 per QALY respectively.
The original modelling was not able to look into the effect of using different hearing loss thresholds, as there is no comparative evidence on the benefit to quality of life of improving hearing for people with different levels of hearing loss. However, sensitivity analysis which dramatically reduced the benefits of hearing aids for the whole population, and sensitivity analysis that increased the proportion of people either not suitable for hearing aids or dropping out after being fitted with hearing aids indicate that even if those people with lower levels of hearing loss benefit by a smaller amount than the average benefit expected in the model, the intervention would still be very cost effective overall.
In addition, the committee noted that there is no standard universal definition of hearing loss. While the BSA criteria fit best with current understanding and practice in the UK, in the Cochrane review the international WHO classification was used. The committee agreed that decision-making on whether to fit hearing aids should not be based on a threshold measurement alone but on a combination of hearing measurement and communication difficulties. The committee therefore agreed that audiologists should be able to use their expertise to assess whether a person would benefit clinically from using hearing aid(s) due to their hearing loss, and if so they should offer hearing aid(s) and discuss this with the person. The committee agreed that provision of hearing aids to all who would benefit from them will be cost effective at a cost-effectiveness threshold of £20,000 per QALY gained.
Other considerationsThe committee acknowledged that there is variation across the UK in whether people with mild to moderate hearing losses receive hearing aid(s) and consider that the decision to fit should be based on need rather than on hearing thresholds. Furthermore, as amplification has been shown to have benefit and is cost effective, hearing aids should be offered at the first opportunity if the individual is likely to benefit.
The committee expressed concern that not providing hearing aids, and the care needed to use them effectively, to a person with an aidable hearing loss, raises serious questions of inequality of access. Hearing aids can make a difference to the ability of a person with hearing loss to communicate effectively and can thus reduce the impact of their impairment. Their impairment is permanent and even a mild hearing loss can have a significant effect on day-to-day functioning.
The NHS England commissioning framework for adult hearing loss provides guidance on how high quality audiology services and pathways can be designed.86

15.3. Review question: What is the clinical and cost effectiveness of fitting 1 hearing aid compared with fitting 2 hearing aids for people when both ears have an aidable hearing loss?a

For full details see review protocol in appendix C.

Table 87. PICO characteristics of review question.

Table 87

PICO characteristics of review question.

No minimum duration of hearing aid use or follow-up was applied as an inclusion criteria to consider studies for review. However, evidence was downgraded for indirectness of evidence if participants had used the hearing aids for 6 weeks or less. The rationale is a period of adjustment is important before the full effects of hearing aid fitting can be properly observed and evaluated.

15.3.1. Clinical evidence

Four studies (5 papers) were included in the review26,41,108,119 47 these are summarised in Table 88 below. Evidence from these studies is summarised in the clinical evidence summary below (Table 88). See also the study selection flow chart in appendix E, forest plots in appendix K, study evidence tables in appendix H, GRADE tables in appendix J and excluded studies list in appendix L.

Table 88. Summary of studies included in the review.

Table 88

Summary of studies included in the review.

Table 89. Clinical evidence summary: Bilateral versus unilateral hearing aids.

Table 89

Clinical evidence summary: Bilateral versus unilateral hearing aids.

Table 90. Summary of preferences results.

Table 90

Summary of preferences results.

15.3.2. Economic evidence

15.3.2.1. Published literature

No relevant health economic studies were identified.

See also the health economic study selection flow chart in appendix F.

15.3.2.2. Original cost-effectiveness analysis

This analysis uses the same costs as used in the cost–utility analysis conducted for this guideline – please see appendix N for sources and further details. The committee agreed that the resources required for a hearing aid for the second ear (above those that would be required for a first hearing aid for 1 ear only) would be the cost of the hearing aid itself, a mould or thin tube and dome, and batteries. In addition, the committee cautiously assumed that people with 2 hearing aids would obtain 1 additional aftercare appointment each year for hearing aid repairs and maintenance compared with people with 1 hearing aid (for example, if people with 1 hearing aid accessed 1 aftercare appointment per year, people with 2 hearing aids might access 2 aftercare appointments per year). The committee agreed that this is likely to overestimate the differential demand for aftercare. It is perhaps more likely that people with 2 hearing aids would access aftercare services a similar number of times, but may require more inputs (such as repairs) during each appointment. However, the committee wished to be cautious in not risking underestimating costs, and so chose to assume that there would be an additional aftercare appointment each year, to represent the maximum possible difference in costs between 1 hearing aid and 2 hearing aids being fitted.

There will be no difference in costs for fitting or follow-up appointments, as an individual will have the same number of appointments whether they are having 1 or 2 hearing aids fitted. This analysis considers a period of 3 years, as that is expected to be the shortest length of time hearing aids would usually be kept before an individual’s hearing is reassessed and they may receive new hearing aid(s). (See also the recommendations regarding follow-up in section 17.3.4. The committee has not recommended a particular frequency of reassessment, and this could be longer than 3 years.) The costs are shown in Table 91.

Table 91. Additional costs of supplying a second hearing aid for an individual’s second ear.

Table 91

Additional costs of supplying a second hearing aid for an individual’s second ear.

It should be noted that the total 3-year cost of £174 is not intended to be a true reflection of the average difference in costs of fitting 1 or 2 hearing aids in a person with bilateral hearing loss, and so this should not be taken as a saving that would be expected if people were given only 1 rather than 2 hearing aids. This figure has been calculated as an upper limit of the potential difference, to ensure that the further calculations below are conservative, and tend towards underestimating rather than overestimating the cost effectiveness of the approach being studied. This difference can be compared against the difference in the NHS England non-mandatory tariffs for fitting 1 or 2 hearing aids. These were £294 compared with £388, a difference of £94, in 2011/12 when the tariff included the costs of 3 years of aftercare.86 These tariffs have since been withdrawn. Local areas have their own tariffs, and in most cases these are lower than the former NHS England tariff for both 1 and 2 hearing aids. Whilst costs will differ depending on locally implemented delivery pathways, this indicates that £174 is certainly an upper bound for the difference in costs, and higher than would reasonably be expected.

To calculate the threshold for the improvement in utility (quality of life) that would be necessary to make this expenditure cost effective at a cost-effectiveness threshold of £20,000 per QALY gained, we need to divide the total cost of £174.08 by £20,000.

This gives a utility increment of 0.0087 QALYs (or, alternatively, 3.2 quality-adjusted life days) over a period of 3 years, or 0.0029 QALYs per year.

There are no published figures for the improvement in utility to be expected by adding a second hearing aid. However, there are figures for the improvement caused by the adoption of hearing aid(s) by people with hearing loss who previously did not have any hearing aids. As discussed in greater detail in appendix N, the committee has agreed that the most appropriate source for this measurement is the study by Barton 2004 using the HUI3 tool which gave this improvement in utility as 0.060 QALYs.11

0.0029 QALYs is 4.8% of 0.060 QALYs.

So if we compare the benefit gained by someone with hearing loss who previously had no hearing aids and adopts hearing aids (0.060 QALYs) with the benefit required by someone with hearing loss in both ears who currently has 1 hearing aid and is now adopting a second hearing aid (0.0029 QALYs) we find that the second person would need to benefit by at least 5% (a twentieth) as much from their second hearing aid as the first person benefits from their hearing aids for this to be cost effective at a cost-effectiveness threshold of £20,000 per QALY gained.

15.3.3. Evidence statements

Clinical

  • There was insufficient evidence to determine if there was a clinically important benefit of using 2 hearing aids compared with 1 hearing aid for the outcomes of patient preference (very low quality evidence, 4 studies), usage of hearing aids, sound localisation and speech in noise detection (very low quality evidence, 5 studies).
  • There was no evidence for any of the other outcomes of interest.

Economic

  • No relevant economic evaluations were identified.

15.3.4. Recommendations and link to evidence

Recommendations
26.

Offer 2 hearing aids to adults with aidable hearing loss in both ears. Explain that wearing 2 hearing aids can help to make speech easier to understand when there is background noise, make it easier to tell where sounds are coming from, and improve sound quality.

27.

For adults with hearing loss in both ears who chose a single hearing aid, consider a second hearing aid at the follow-up appointment.

Relative values of different outcomesThe following outcomes were identified as critical for this review: hearing-specific health-related quality of life, health-related quality of life, listening ability, outcomes reported by carers or ‘communications partner’ and patient preference.
Important outcomes agreed were usage of hearing aids (including from data logging and self-reported), adverse effects (pain, infection), annoyance scale in patient reported outcome measures, sound localisation as measured by laboratory tests and speech in noise detection as measured by laboratory tests.
Quality of the clinical evidenceThe quality of evidence for all outcomes reported was very low. This was mainly due to the following:
  • Risk of bias because none of the studies had described methods of randomisation and allocation concealment methods, and because of lack of blinding of assessors and no indication that outcome measures were validated. One study used alternation (quasi-randomised), whereas 2 other studies did not describe sequence generation method. Risk of detection bias from lack of blinding is high because the outcome was subjective. In addition 3 of these studies did not describe the protocols for fitting.
  • Imprecision due to small sample sizes.
  • Indirectness as the largest study randomised participants to 1 week phases of each fitting before asking patients to use the hearing aids as they liked for another 9 weeks, while another study only fitted patients alternately for 1 hour before trialling the other option. It was uncertain if the 1 week period is sufficient for patients to get used to the fitting.
Evidence was available for patient preference and usage. Sound localisation and speech detection were also reported by 1 study.
For the patient preference data, all studies asked patients which arrangement they preferred at the end of the trial. Two of these studies randomised patients to 3 groups, with 2 groups randomised to either the left ear or the right ear and 1 randomised to both ears. Therefore, the randomisation was 2:1 rather than 1:1. The direction of bias is uncertain.
The third study randomised equal numbers of patients to bilateral and unilateral fitting before crossing these over, but all the participants in the study had chosen to be fitted with hearing aids unilaterally prior to randomisation. This indicates a potential bias favouring unilateral fitting, possibly due to a prior preference of participants or information received. The other study allocated people by alternation to 1 hour of bilateral and unilateral use each.
For usage of hearing aids, although the 3 studies reported this outcome, data from 2 of these cannot be used because they reported the mean daily usage according to the preferred fitting by the participants rather than usage while being allocated to unilateral versus bilateral hearing aids. These results do not tell us whether someone will use hearing aids more when they are allocated 1 or 2 hearing aids.
The information for usage, sound localisation and speech in noise detection was measured using a questionnaire at the end of each 10-week phase. It is uncertain if the questionnaire was validated and how the data were collected. It was impossible to blind outcome reporting, but unclear if the person collecting the data from the patient was a ‘neutral’ party or someone involved in delivery of the intervention.
The potential benefits of speech in noise detection and sound localisation needed to be measured against the overall benefit from using the hearing aids, such as quality of life. However, there were no data for this.
It was noted that the evidence was from very old studies conducted over 20 years ago when most hearing aids were likely to be either analogue or much less technologically advanced. This may have influenced the ability of the patients to use them and may have affected their preferences. In addition, as attitudes and beliefs change over time, this may also influence patient preference and this may impact the applicability of results derived from studies conducted many years ago.
Due to the very low quality of the evidence and the uncertainty around it as well as the lack of evidence for many of the outcomes of interest, it was difficult to ascertain whether there was a clinically important benefit of fitting 2 hearing aids compared with 1 hearing aid.
Trade-off between clinical benefits and harmsThree studies reported that the preference for unilateral versus bilateral fitting of hearing aids was roughly divided equally, while another study suggested more people had a preference for bilateral hearing aid fitting. The only study that provided more information to suggest some benefits of unilateral fitting (in terms of usage, sound localisation and speech in noise detection) was also the study that had a higher preference for unilateral fitting (60%). Of patients with an initial preference for a unilateral hearing aid, 40% changed their mind after trying bilateral hearing aids.
The committee noted that current practice, based on the NHS England commissioning framework,86 is to prescribe and fit hearing aids bilaterally when there is a bilateral aidable hearing loss. The clinical experience of the group corroborates the potential benefit of bilateral fitting of hearing aids for restoring binaural hearing, although no evidence was identified to support this. There is, however, evidence that shows 2 ears are better than 1 and also laboratory evidence showing the benefit of 2 hearing aids. In the absence of good quality evidence with direct applicability, the committee decided to reinforce current practice in the recommendations, though also highlighting the importance of patient choice. The studies were all of a short duration and the group considered that these timings were not long enough for people to make an informed choice. Adequate time (with appropriate information) needs to be given to enable people to get used to wearing hearing aids, along with a follow-up appointment to provide any adjustments to the devices and support to enable continued usage. The committee agreed that bilaterally worn hearing aids have the potential to facilitate communication as sound quality may be better than with a unilaterally worn hearing aid. The impact on family and carers’ ability to communicate with the person also needs to be considered.
The committee also considered the balance of benefits and potential disadvantages of binaural stimulation. The benefits include improved: intelligibility of speech in background noise, sound localisation, and sound quality. It also has the potential to avoid deficits that may develop over time if only 1 hearing aid is fitted and the unaided ear is deprived of stimulation. The NHS England commissioning framework notes that “Fitting of bilateral hearing aids is beneficial as many modern hearing aids interact with each other to offer greater improvement in speech discrimination in everyday environments”. On the other hand, potential disadvantages of bilateral fitting include additional cost (to the NHS), a perception from some that 2 devices may be too complex for some people to use, and, for a few, binaural interference (that is, reduced speech intelligibility compared with performance with a single device).
Trade-off between net clinical effects and costsNo published health economic evaluations were identified for this question.
The committee noted a lack of clear clinical evidence, and so the effect on quality of life could not be quantified. However, the committee is aware of the basic scientific research that demonstrates the acoustic advantage of wearing 2 hearing aids and noted that the NHS commissioning framework recommends that providing 2 hearing aids should be standard practice.
An original cost threshold analysis was therefore undertaken to consider the difference in costs between prescribing and fitting hearing aids unilaterally and bilaterally. The number of appointments and time taken to prescribe and fit hearing aids would not differ significantly between the process of fitting a single hearing aid and that for fitting 2 hearing aids bilaterally. There would however be increased costs for a second hearing aid (average £71), associated mould or thin tube and dome (£3) and batteries (£4 per year). For the purpose of this analysis the committee assumed that the hearing aid would be used for 3 years before being replaced, and that the user would seek 1 extra aftercare appointment for hearing aid maintenance (£30) each year. This gives a total additional cost of £174 over 3 years for providing a second hearing aid.
When compared with the NICE cost-effectiveness threshold of £20,000 per QALY gained, this means that to be cost effective the addition of a hearing aid for the second ear would need to lead to an average increase in health-related quality of life of 0.0029 QALYs per year during the 3 years in which it is in use. This is equivalent to 4.8% of the benefit (0.06 QALYs per year) conferred by hearing aid use compared with no hearing aid use found by Barton 2004,11 which was used as the basis of the calculation of quality of life gain in the original economic modelling for this guideline (appendix N). That is, if the benefit of adding the second hearing aid is 5% or more of the benefit found from using hearing aids compared with using none, then it is cost effective to provide 2 hearing aids.
The committee was confident that the benefits of bilateral hearing would be considerably greater than this threshold, and hence bilateral hearing aids would be cost effective. The committee also noted that the original economic modelling for this guideline assumed that all people receiving treatment would have bilateral hearing loss and be provided with 2 hearing aids, and on this basis both early and delayed provision of hearing aids were found to be highly cost effective compared with no hearing aid use at a cost-effectiveness threshold of £20,000 per QALY gained. As a result the committee agreed to recommend that the current practice of offering 2 hearing aids to people with hearing loss in both ears should be continued.
Other considerationsIn 1 study the population was made up of military personnel and the committee noted that some people would have concerns about any impact hearing loss might have on their employment and career opportunities and may base their choices on these factors.
The committee noted that some people who initially opt to have a unilateral hearing aid would later be willing to undergo a trial of a second hearing aid in the other ear – either due to a change of mind or due to deteriorating hearing. The need for follow-up was also identified as one of the main findings that is important to people with hearing loss (see section 12.2.4).
The recommendations highlight the importance of follow-up for continued use of hearing aids. People should be offered the opportunity to either add or reject a hearing aid after trying out the option they initially chose.
The committee noted evidence from 1 study following up people 12 years after they first had hearing aids fitted, which found that agreeing to have 2 hearing aids fitted rather than only accepting 1 hearing aid was strongly associated with an increased chance that the person would still be using hearing aids 12 years later.28
Although the NHS England commissioning framework recommends prescribing and fitting 2 hearing aids for bilateral hearing loss,86 the committee highlighted anecdotal evidence indicating variation in practice geographically with some areas of the country routinely initially prescribing 1 hearing aid. The committee was concerned with this approach and emphasised that prescribing 2 hearing aids is cost effective compared with prescribing 1 hearing aid.

Footnotes

a

This review was developed in collaboration with Cochrane.

Copyright © NICE 2018.
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