Is Unilateral Cochlear Implantation Cost‐Effective for the Treatment of Bilateral Sensorineural Hearing Loss?

Abstract

Cochlear implantation (CI) has revolutionized auditory rehabilitation for adults and children with bilateral severe to profound sensorineural hearing loss (SNHL). Successful CI is associated with improvements in hearing performance, speech perception, and quality of life (QOL). However, it is estimated that the current market penetration is <20% in developed countries and an even more dismal <1% in developing countries, in large part due to the high cost of CI. This prompts the question: Is unilateral CI cost-effective for the treatment of bilateral SNHL? Cost-effectiveness analysis compares the direct and indirect costs of intervention versus the improvement in QOL and reduction in healthcare costs. It is often measured by cost per quality-adjusted life-year (QALY); QALY is a generic measurement of disease burden on life that considers both quantity and QOL. One QALY equates to 1 year of life in a perfect state of health and has a range from 0.00 (death) to 1.00 (perfect health) on a linear scale. It is usually measured by questionnaires such as the Health Utilities Index (HUI), Time-Trade-Off (TTO), or a visual analog scale (VAS). Additionally, to compare the cost-effectiveness of two different interventions, the incremental cost effectiveness ratio (ICER) is calculated by taking the ratio between the difference in costs and the difference in QALY of two interventions. In the United States, acceptable cost-effectiveness ratios are typically <$50,000/QALY, a threshold that arose from literature in the 1980s describing the costs of dialysis in end-stage renal disease. Such thresholds reflect a society's willingness to pay, which can vary considerably among healthcare systems. In adults with severe to profound bilateral SNHL, there is mounting evidence supporting the cost-effectiveness of unilateral CI compared to bilateral hearing aids (HAs) alone. For example, Cheng and Niparko1 conducted a meta-analysis of seven studies evaluating the cost-effectiveness of CI in adults with profound SNHL and found it to be overwhelmingly favorable. In this pooled analysis of 619 patients, cost-effectiveness ratios were calculated in terms of life-years weighted by HUI. The HUI of profoundly deaf adults after CI was 0.80 (95% confidence interval: 0.78-0.82), compared to 0.54 (95% confidence interval: 0.52-0.56) without CI. This difference of 0.26 HUI equated to a favorable ratio of $12,787 per QALY for CI. The authors pointed out that this figure compares favorably with other interventions commonly covered by third-party payers in the United States such as percutaneous coronary interventions and total hip arthroplasty. Similar findings were reported by Palmer et al.2 in a prospective, multicenter study of adults with bilateral severe to profound SNHL undergoing unilateral CI. In this study, health utility was measured using the HUI and compared between implanted (n = 64) and nonimplanted (n = 22) patients. The preintervention mean HUI scores were indistinguishable between groups (implanted = 0.58 ± 0.17 vs. nonimplanted = 0.58 ± 0.20, P > .05). However, 6 months after CI, the mean HUI score for implanted patients was substantially higher than for nonimplanted patients (implanted = 0.76 ± 0.18 vs. nonimplanted = 0.57 ± 0.18, P < .001). The mean incremental cost was $14,670 per QALY for implanted patients versus nonimplanted patients, which the authors argue indicates a high level of cost-effectiveness for CI in adults in the United States. Laske et al.3 investigated the effect of patient age on the cost-effectiveness of CI. They designed a Markov model to determine the ICER of unilateral CI compared to bilateral HAs as a function of age and sex. The ICER for unilateral CI compared to bilateral HAs increased with age, indicating a decrease in cost-effectiveness with increasing age at implantation. This is intuitive, given that with increasing age, fewer years of life remain during which benefit can be derived from the CI. For example, when a 20-year-old woman received a unilateral CI, the ICER compared to bilateral HAs was ~$6,372 USD/QALY, as opposed to an 80-year-old woman who under the same circumstances exhibited an ICER of ~$22,390 USD/QALY. Nevertheless, unilateral CI remained cost-effective compared to bilateral HAs up to age 91 for women and age 89 for men. Taken together, these data indicate that unilateral CI is cost-effective for adults with bilateral profound SNHL. In the pediatric population, there is also compelling evidence supporting the cost-effectiveness of unilateral CI. Cheng et al.4 conducted a cost-effectiveness analysis of 78 profoundly deaf children and found unilateral CI to be cost-effective compared to bilateral HAs. For this analysis, cost utility was measured using preintervention, postintervention, and cross-sectional surveys. It was calculated as the direct and total cost to society per QALY, where QALY was expressed in life years weighted by each of three different instruments that measure health-related QOL: 1) TTO, 2) VAS, and 3) HUI. Compared to before CI, TTO, VAS, and HUI all increased after CI. Mean TTO scores increased from 0.75 (95% confidence interval: 0.67-0.83) to 0.96 (95% confidence interval: 0.93-1.00), mean VAS scores increased from 0.59 (95% confidence interval: 0.53-0.64) to 0.86 (95% confidence interval: 0.83-0.89), and mean HUI scores increased from 0.25 (95% confidence interval: 0.16-0.34) to 0.64 (95% confidence interval: 0.57-0.70). This translated to effective direct medical costs per QALY, including $9,029/QUALY for TTO, $7,500/QALY for VAS, and $5,197/QALY for HUI, and equated to an estimated net savings of $53,198 over a child's lifetime. Similar to adults, delaying implantation to an older age can reduce the cost-effectiveness of CI. Semenov et al.5 conducted a prospective, multicenter, longitudinal assessment of health utility and educational placement outcomes in 175 children with severe-to-profound bilateral deafness who underwent CI before 5 years of age. They found that children implanted at <18 months of age gained an average of 10.7 QALYs over their projected lifetime at a cost of $14,996/QALY, compared to 8.4 QALYs for those implanted at >36 months of age at a cost of $19,173/QALY. The classroom integration rate was higher for children implanted at <18 months of age (81%) compared to at >36 months of age (63%). The net societal savings (which incorporated lifetime educational cost savings as well as cost/QALY) of CI was $31,252 for children implanted at <18 months compared to $6,680 for children implanted at >36 months. Thus, like adults, CI is also cost-effective for children with bilateral profound SNHL, and this effectiveness depends upon age at implantation. Unilateral CI is cost-effective for both adults and children compared to bilateral HAs; its cost effectiveness is greater when implanted at a younger age. The ongoing development of validated, disease-specific instruments for measuring improvements in QOL related to CI use will aid in making the most accurate estimates of cost-effectiveness. Two prospective cost-effectiveness studies (level 2), one meta-analysis (level 2), and two retrospective cost-effectiveness studies (level 3) were included.