Is Bilateral Cochlear Implantation Cost‐Effective Compared to Unilateral Cochlear Implantation?

Bilateral cochlear implantation (BCI) can be performed either simultaneously or sequentially in children and adults with severe to profound bilateral sensorineural hearing loss (SNHL). It offers several advantages over unilateral cochlear implantation (UCI) including improvement in speech perception in noise, better sound source localization, and reduced effort required to hear. However, BCI is costlier than UCI largely due to the cost of the second device. The higher cost prompts the question of whether BCI is cost-effective compared to UCI. Cost-effectiveness analysis compares one intervention with another with respect to both costs and health outcomes. Cost-effectiveness is usually expressed in terms of quality-adjusted life years (QALY) (Table 1). Common questionnaires that measure healthy utility, a numerical rating assigned to patient's quality of life (QOL), which is an important component of the QALY, include the Health Utilities Index (HUI), time trade-off (TTO), and visual analog scale (VAS). When a QALY is expressed as a function of net treatment cost, it is referred to as an incremental cost-utility ratio (ICER). Whether or not an intervention is deemed cost-effective depends upon whether a given ICER is less than the willingness-to-pay (WTP) threshold for a given healthcare system (Table 1). In children, the cost-effectiveness of BCI compared to UCI depends upon several factors including method of delivery (simultaneous vs. sequential), health utility gained by the second implant, and anticipated discounts offered on the second implant. Pérez-Martín et al.1 conducted a retrospective cost-effectiveness analysis of 273 children in Spain with bilateral SNHL and found that BCI was cost-effective compared to UCI. In this study, children received UCI, sequential BCI, or simultaneous BCI. The authors used the TTO method to measure health utility and constructed a Markov model to predict cost-effectiveness over time. Compared to UCI, the ICERs for simultaneous and sequential BCI were €10,323/QALY and €11,733/QALY, respectively, which are well below the WTP threshold in Spain of €30,000/QALY. Bond et al.2 performed a systematic review and pooled cost-effectiveness analysis of children with bilateral SNHL in the United Kingdom. Compared to UCI, the ICERs for simultaneous and sequential BCI were £40,410/QALY and £54,098/QALY, respectively. According to the authors, when applying a WTP of £30,000/QALY, simultaneous BCI only became cost-effective when a discount of approximately 60% was assumed on the second CI. According to the United Kingdom's National Institute for Health and Care Excellence, discounted rates offered by manufacturers on the second CI typically range from 0% to 50%. It is important to note that ICER estimates in these studies depend upon a set incremental utility gain, which reflects the amount of clinical benefit that is afforded by the second CI. When utility gain is increased, the ICER is reduced, reflecting increasing cost-effectiveness. However, accurately estimating utility gain is challenging, particularly in children, where it is determined by clinicians, researchers, and parents and not by the patients themselves. Variations in utility gain between studies can dramatically impact ICERs, thereby making interventions appear either more or less cost-effective. This is one explanation for the large cost discrepancy observed between the ICERs described by Pérez-Martín et al.1 compared to those described by Bond et al.2 To increase the accuracy of ICER estimates, more longitudinal research in the pediatric population comparing utility changes associated with UCI versus BCI is necessary. In the adult population, evidence for the cost-effectiveness of BCI compared to UCI has been mixed. For example, Smulders et al.3 reported that BCI can be cost-effective for adults, but only after prolonged periods. In this multicenter, prospective, randomized controlled trial of 38 Dutch-speaking adults with bilateral SNHL, patients either underwent UCI (n = 19) or simultaneous BCI (n = 19). Health utility was measured for hearing (HUI, TTO, and VAS questionnaires) as well as general QOL. Interestingly, although BCI was not found to be cost-effective in terms of general QOL, it did become cost-effective over time in terms of hearing outcomes. When the authors assumed a WTP threshold of €80,000/QALY, simultaneous BCI was cost-effective compared to UCI after 5 to 10 years based on VAS hearing questionnaires, and after 10 to 25 years based on TTO and HUI hearing questionnaires. The authors point out that in the Netherlands, acceptable WTP thresholds vary between €24,500/QALY and €80,000/QALY depending upon the seriousness of the disease. If a more conservative WTP threshold were applied, the time required to reach cost-effectiveness would likely have exceeded 25 years; thus, given an average life expectancy of ~79 years, BCI would not be cost-effective in those older than 54 years. Chen et al.4 performed a cost-effectiveness analysis in adult patients with bilateral SNHL in Canada who received either UCI or sequential BCI. Health utility was measured by the HUI method. The ICER for BCI compared to UCI was $55,020/QALY. This value varied inversely with duration of use, with shorter use periods producing higher ICERs. The ICER for BCI also varied according to estimated discounts for the second implant. For example, if a price reduction of 75% for the second implant was assumed, the ICER for BCI compared to UCI was to $47,591/QALY. These results suggest that in adults, sequential BCI is borderline cost-effective compared to UCI, and cost-effectiveness improves both with greater discounts on the second implant and longer CI use periods. Trinidade et al.5 performed a retrospective theoretical cost analysis comparing sequential and simultaneous BCI in adults. The authors hypothesized that the potential savings of simultaneous BCI compared to sequential BCI would depend upon the proportion of UCI patients that ultimately transition to BCI. They point out that other comparative cost-effectiveness studies have assumed a 100% conversion rate from UCI to BCI, which is an overestimate. In the study sample, only 27.3% of UCI patients ultimately converted to BCI. According to their cost analysis, simultaneous BCI in all qualifying patients only becomes cost-effective compared to sequential BCI when at least 22.1% of patients who undergo UCI are expected to convert to BCI. Combined results from all studies are summarized in Table 2. In children, BCI is cost-effective compared to UCI, particularly when it is performed simultaneously, and the second implant is significantly discounted. In adults, cost-effectiveness of BCI compared to UCI is borderline; it is greatly influenced by cost of the second implant and probable duration of use. Thus, in both children and adults, the cost-effectiveness of BCI would be significantly improved with the availability of a cheaper cochlear implant. Further longitudinal studies comparing improvements in healthy utility between patients with UCI and BCI are necessary, particularly in the pediatric population, to increase the accuracy of future cost-effectiveness analyses. One prospective, randomized study (level 1), one systematic review (level 2), and three retrospective cost-effectiveness studies (level 2) were included.