General Health Quality of Life Instruments Underestimate the Impact of Bilateral Cochlear Implantation.

OBJECTIVE: To determine the extent to which bilateral cochlear implantation increases patient-reported benefit as compared with unilateral implantation and no implantation. DATA SOURCES: PubMed, Scopus, CINAHL, and Cochrane databases searches were performed using the keywords ("Cochlear Implant" or "Cochlear Implantation") and ("bilateral"). STUDY SELECTION: Studies assessing hearing/CI-specific (CI) and general-health-related (HR) quality of life (QOL) in adult patients after bilateral cochlear implantation were included. DATA EXTRACTION: Of the 31 articles meeting criteria, usable QOL data were available for 16 articles (n = 355 bilateral CI recipients). DATA SYNTHESIS: Standardized mean difference (Δ) for each measure and weighted effects were determined. Meta-analysis was performed for all QOL measures and also independently for hearing/CI-specific QOL and HRQOL.
CONCLUSION: When measured using hearing/CI-specific QOL instruments, patients reported very large improvements in QOL comparing before cochlear implantation to bilateral CI (Δ=2.07 [1.76-2.38]) and medium improvements comparing unilateral CI to bilateral CI (Δ=0.51 [0.32- 0.71]). Utilization of parallel versus crossover study design did not impact QOL outcomes (χ = 0.512, p = 0.47). No detectable improvements were observed in either CI transition when using HRQOL instruments (no CI to bilateral CI: Δ=0.40 [-0.02 to 0.81]; unilateral CI to bilateral CI: Δ=0.22 [-0.02 to 0.46]).The universal nature of HRQOL instruments may render them insensitive to the medium to large QOL improvements reported by patients using hearing/CI-specific QOL instruments. Given that HRQOL instruments are used to determine the economic benefit of health interventions, these measurement differences suggest that the health economic value of bilateral cochlear implantation has been underestimated.