Table 2.

Characteristics of included studies that examined health service utilisation of CI users

Authors and publication year	Objective or aim	Health service utilisation measures	Key findings
Aldhafeeri et al., 2021 [90]	To discuss experience of managing cochlear implant cases that required revision surgery.	CI revision surgery (with or without reimplantation).	Overall, four CI revision surgeries were performed. The main reasons for revision were device failure, surgical (misplaced) or medical (infection) related.
Chen et al., 2022 [91]	To determine factors related to need for cochlear implant revision surgery, to identify the rate of revision surgery, and to elucidate the cumulative survival and device survival in different age groups.	CI revision surgery.	Of the 929 CI users aged ≥ 18 years, 10 CI revision surgeries were conducted. A revision rate of 1.1%. Three device failures (n = 2 hard and n = 1 soft failure) and seven non-device (i.e., n = 3 electrode displacements; n = 1 infection; n = 1 mis-insertion; n = 1 device migration; n = 1 facial paralysis) were the reasons for the revision. The mean ± SD for 5-year cumulative and device survival rates were 98.7 ± 0.4% and 99.5 ± 0.3%, respectively.
Carpenter et al., 2010 [49]	To increase vaccination rates for bacterial meningitis using information dissemination through brochure and electronic media, and ongoing reminder for CI users.	Pneumococcal vaccination utilisation was collected using ongoing mailed, email, phone call and patients’ medical record review.	Pneumococcal vaccination rates increased from 49–99% following CI. Majority of CI users received vaccination only after the follow-up reminder.
Cole et al., 2022 [97]	To determine the association of chronological age and frailty as measured by 5- and 11-factor modified frailty index (mFI-5, mFI-11) on post-operative outcomes of participants undergoing CI.	Extended hospital length of stay (i.e., > 75th percentile of study population) average and standard deviation in days and non-home discharge destinations post-CI using the Modified Frailty Index (mFI-5 and mFI-11) [106].	Increased frailty of CI users likely associated with extended length of hospital stay and non-home discharges. Of the 5130 CI users, 320 (6.2%) were discharged to a non-home destination, such as aged care centre.
Guitar et al., 2013 [50]	To determine whether people on a waiting list for CI are more likely than those who have a CI to suffer from illnesses which are potentially mediated by stress.	Number of physician visits and medication use in the past year were assessed using 21-item Depression, Anxiety and Stress Scale (DASS-21) [107], the Short-form health questionnaire (SF-36) [108], and self-rated dissatisfaction with hearing.	Time since implantation was 5.73 years (range 375–6653 days) for CI group. Individuals on the waiting list waited on average for 18 months (range 45-1960 days). Participants on waiting list visited a physician on average 6.2 times (SD ± 4.8) a year while participants with CI visited 4.3 times (SD ± 3.7). Participants on the waiting list took prescription medication on average for 3.1 illnesses (SD ± 2.4) while those with a CI took prescription medication on average for 1.8 illnesses (SD ± 1.9). People on the waiting list were more likely to take prescription medication for migraines, ear infections, and sleep disturbance compared to people with a CI. The overall psychological distress, specifically anxiety and stress were higher in the waiting list group compared to people with a CI.
Gumus et al., 2021 [92]	To determine reasons for CI revision surgeries in paediatric and adult groups.	CI revision surgery	Overall, six CI revision surgeries were performed, and the revision surgery rate was 1.4%. Three device failures (i.e., hard failures (n = 2), and soft failure due to voice problem (n = 1). Three medical-related problems (i.e., flap skin infections (n = 2) and chronic otitis media (n = 1)).
Kay-Rivest et al., 2022 [94]	To evaluate the frailty phenotype in a population of older adults and determine the association of frailty with (i) preoperative complications, (ii) need for vestibular rehabilitations after surgery, and (iii) early speech perception outcomes.	(1) Post-operative vestibular/aural rehabilitation post-CI assessed by the Fried Frailty Index [109] and patients’ medical records. (2) CI revision	There were 10 pre-frail, 5 frail, and 31 non-frail users. (1) The number of missed follow-up visits (combined surgeon, audiologist, speech language pathologist visits) was higher for frail patients (n = 7 visits; range 1–10 visits) compared to pre-frail (n = 3 visits; range 0–4 visits) and non-frail (n = 2 visits; range 0–5 visits) users. (2) Four users developed vertigo, three users required vestibular rehabilitation, one user had a post-operative fall, and one had complication that required implant revision.
Raymond et al., 2020 [48]	To determine the association between geriatric age and post-operative healthcare utilisation post-CI.	Post-operative surgical and audiological visit rates up to 2 years post-CI, along with phone calls to the otology and audiology departments recorded in the electronic health record (eMR) after their surgery related to their CI surgery or implanted device using patients’ medical record.	The mean duration of hearing loss was 25.4 years, and the mean duration of follow-up post-CI was 37 months. In the first post-operative year, there was 1.9 ± 1 mean ± SD number of surgical visit for 60 to 69 years old, 1.9 ± 0.8 visits for 70 to 79 years old and 2 ± 1.8 visits for individuals aged ≥ 80 years and the mean number of audiological visits was 5.4 ± 1.5 for 60 to 69 years old, 5.5 ± 0.7 for 70 to 79 years old and 5.6 ± 0.7 for individuals aged ≥ 80 years. The number of phone calls in the first post-operative year were 0.9 ± 1.4 for 60- to 69-year-olds, 1.7 ± 2.5 for 70 to 79 years old and 1.2 ± 1.2 for individuals aged ≥ 80 years old. In the second post-operative year, the mean numbers of surgical visits decreased by 0.12 ± 4.3, 0.17 ± 3.8, and 0 by each age group and audiology visits in the second year were 1.4 ± 1.4, 1.3 ± 0.9, 1 ± 1.3 by age group, respectively. The number of phone calls in the second post-operative year were 0.3 ± 0.5 for 60 to 69 years old, 0.5 ± 0.8 for 70 to 79 years old and 0.1 ± 0.3 for individuals aged ≥ 80 years. There was no significant difference in health service utilisation between the age groups.
Sorrentino et al., 2016 [96]	To evaluate cochlear implant revision surgery experience and to compare with available literature.	CI revision surgery	Of 286 CI users originally with profound sensorineural hearing loss, 11 (3.8%) adults underwent CI revision surgery, with two adults undergoing reimplantation twice. Device failure including hard failure (n = 7) and soft failure (n = 4), and medical-related (n = 9) were reported as the main reasons for revising surgery. Four adults had revision surgery due to a flap skin infection.