A systematic review of the economic literature of cochlear implants (CI) was conducted with the aim of summarizing the results of studies on the cost effectiveness of monolateral and bilateral (sequential/simultaneous) CI in adult patients affected by severe to profound prelingual and postlingual hearing impairment. The literature search was performed using “PubMed MEDLINE” and the Centre for Reviews and Dissemination search engines. Inclusion criteria related to economic evaluation included primary studies published in English language from January 2000 to May 2010 and aimed to quantify costs of CI and compare monolateral CI vs. acoustic prosthesis and bilateral (sequential/ simultaneous) CI vs. monolateral CI in terms of cost per unit of effectiveness. Four articles were identified. The mean direct medical cost of the monolateral CI varied from € 30,026 to € 45,770 in postlingually deafened patients, and the cost of device represented the main cost component. Additional median costs of simultaneous and sequential bilateral CI were, respectively, € 21,831 and € 25,459. The mean direct medical cost of monolateral CI was € 31,942 in prelingually deafened patients. The monolateral CI in postlingually deafened patients represented a cost effective intervention as compared with no implant (€ /QALY varied from € 7,930, € 24,983 to € 33,094). Monolateral CI were not a cost effective intervention for traditional patients with more than 40 years of hearing impairment (€ 64,604/QALY ) or for patients with marginal benefits from using acoustic prosthesis with more than 30 years of hearing impairment (€ 106,267/QALY ). The cost effectiveness of monolateral CI worsened with increasing age (€ /QALY from € 23,439 for patients < 30 years old to € 55,369 for patients > 70 years). Bilateral CI in postlingually deafened patients were less cost effective than monolateral CI (from € 91,943/QALY to € 102,640/QALY ). Monolateral CI were cost effective in prelingually deafened patients (€ /QALY : € 8,096). Given the few economic evaluation studies in literature, future researches are needed to support the cost effectiveness results of CI in adults and to evaluate the cost effectiveness of bilateral CI, as well as to estimate the non-medical direct and indirect cost components
