Introduction
One alternative to the standard SES programme would be to not have a programme at all. The systematic review in the 2007 HTA report12 described one poor quality study that compared screening with no screening, but the results were inconclusive.16 The updated systematic review reported here in Chapter 2 failed to identify any further studies.
In 2005, one in eight of all services in the UK responsible for implementing a universal school entry hearing screen were no longer doing so.12 Approximately half of those services ran no screen and the remaining half offered a targeted screen for children identified as most at risk. The reasons given for not running a universal screen were based mainly on practical issues, including lack of resources, rather than any research-based evidence. There is no evidence whether implementing a screen at school entry leads to a heightened awareness and hence no failure to identify hearing impairment in children, or whether it results in children, who would otherwise be identified by the screen, slipping through the net and ultimately either never being identified or being identified much later in their school career.
In this chapter we compare two areas of the UK, one with a standard SES programme (Nottingham) and one without such a programme (Cambridge).
Methods
Routine data were analysed to compare data on referrals between a site with SES (Nottingham) and a site without SES (Cambridge).
Background to study sites
Site with a school screen (Nottingham)
The CHAC is a third-tier service and is part of Nottingham Audiology Services within Nottingham University Hospitals NHS Trust. There is no separate second-tier audiology service for children within Nottingham, therefore, all children referred are seen within the same service. CHAC provides services for all children up to the age of 16 years (19 years if in special education) within the catchment area of Nottingham City, Rushcliffe, Erewash, Ashfield, Broxtowe and Gedling. It also accepts referrals from surrounding areas for specialised services. The service is led by a band 8a Clinical Scientist (CB) and has six whole-time equivalent (WTE) audiological staff ranging from band 6 to 8a. CHAC has an open referral policy and therefore accepts referrals from parents as well as from all professionals. It works closely alongside the ENT Department at Nottingham University Hospitals and children move between the two services depending on their needs. The service has around 3400 new referrals a year with a total number of 5900 patient appointments on average.
The service assesses children’s hearing according to national and local protocols and provides counselling and advice to parents with any concerns regarding their child’s hearing. If a child is identified as having a transient conductive impairment, they are referred onto ENT as appropriate after monitoring. For those children identified as having a permanent impairment and those children with a transient conductive impairment whose parent(s) choose not to have surgical management, the service provides hearing aids and ongoing habilitation ().
Pathway for Nottingham patients. CHI, conductive hearing impairment.
All schools within the Nottingham City and County authorities carry out the school entry hearing screen as part of the school entry health screen.
Site with no school screen (Cambridge)
The Cambridge service is a second-tier service provided by Cambridge Community Paediatric Audiology Service, which is part of the Cambridgeshire Community Services (CCS) NHS Trust. It receives approximately 1800 new referrals per year with a total of approximately 2400 appointments annually. The service provides second-tier hearing assessment for children aged 7 months to 16 years (19 years if in special education) and information and education to carers and professionals. The catchment area covers children living in, attending school in or with a GP in Cambridge City, or South and East Cambridgeshire. The service is provided by two community paediatricians (total 1.3 WTE, one of which is clinical lead for the service), one WTE band 7 lead clinical scientist (Audiology) (JM), members from the Addenbrooke’s Paediatric Audiological Team who provide sessional coverage, and administrative support provided by members of the Clinical Support Team attached to Children’s Services within CCS.
The service is provided within family-friendly environments located in the community. A community paediatrician and an audiologist usually run each clinic by working together, using their own areas of expertise, to look at the whole child.
Referrals are made to the service from GPs, child and family nurse team/health visitors, speech and language therapists, paediatricians, education, social services, and the Newborn Hearing Screening Programme (NHSP). When a chronic or permanent hearing impairment is identified the service aim is to facilitate further assessment and management within third-tier services, that is, the tertiary audiology service at Addenbrooke’s Hospital, the ENT department at Addenbrooke’s Hospital, and speech and language therapy.
The role of the service is to assess children’s hearing, according to national and local protocols, for children referred due to carer or professional concern. It also includes assessment of children who have been identified to be ‘at risk’ by the NHSP despite clear responses on the screen. The main condition seen in the second tier is transient conductive hearing impairment associated with middle ear effusion or ‘glue ear’. The second tier provides carers and professionals with information and education regarding this type of hearing impairment and good strategies for supporting the child. If the middle ear effusion or conductive hearing impairment is persistent there are agreed written protocols for referring these children to the ENT Department at Addenbrooke’s Hospital. If a child is identified as having a sensorineural (unilateral or bilateral) hearing impairment, the child will be referred to the Tertiary Paediatric Audiology Service at Addenbrooke’s Hospital for diagnostic assessment and management; this includes any child where it has not been possible to exclude a sensorineural hearing impairment. Referrals to the second tier are often made in order to exclude a hearing impairment as a contributing factor to educational, behavioural and/or speech and language concerns. This includes children who may go on to be identified as being on the autistic spectrum. A diagrammatic representation of the pathway of care for Cambridge is shown in .
Pathway for Cambridge patients. CPAS, Community Paediatric Audiology Service; CHI, conductive hearing impairment; CUHFT, Cambridge University Hospitals Foundation Trust (third-tier hospital).
There has been no SES in Cambridge City, South and East Cambridgeshire since 1997, when the health visitor distraction testing was abolished in this area. Reasons for stopping included cost, variability of practice and lack of strong guidance from the Department of Health on what should be provided for SES and how it should be implemented. Community Paediatric Audiology in CCS was set up in 1997 with a strong campaign to first-tier services (GP, speech and language therapists, etc.) informing them that there would be no routine hearing tests in Cambridgeshire and emphasising the importance of referring to second-tier services if there are parental and professional concerns. This involved letters to all GP practices and health visiting teams, and speech therapy services outlining the changes in provision of routine hearing tests, and posters in GP practices and speech therapy clinics, highlighting the presenting symptoms of glue ear.
Data collection
Data were collected for children aged between 3 years and 6 years 364 days who were referred to Nottingham paediatric audiology or Cambridge audiology services by any source other than the UNHS. All referrals between 1 September 2012 and 30 June 2014 were included. Data on follow-up appointments that took place up to 30 September 2014 were included.
We originally proposed to explore retrospective data collected in Cambridge from 2007 to 2012. However, as those data were not collected with the objectives of the research in mind, much information was missing and it was decided that analyses would not add constructively to the project.
The collaborating audiologists for the areas of Nottingham (site with SES) and Cambridge City, and South and East Cambridgeshire (site without SES) collected data on referrals. Further data were collected via questionnaire from parents of children referred from the SES programme to the Nottingham service (see Chapter 6). Prospective data were processed using a database built by PenCTU.
Audiologists entered data from patient notes. In Nottingham, the waiting list co-ordinator identified eligible children, and audiologists within the service with permission to access patient records entered the data. In Cambridge assistance was also provided by one of the Nottingham researchers. Data were entered for the complete care pathway, from referral through to discharge (or 30 September 2014, whichever occurred first) including: date of birth; postcode; date of referral; location of clinic; referral source (GP, health visitor, school screen, etc.) date of appointment(s); type of assessment (e.g. visual reinforcement audiometry, play audiometry in the soundfield, PTA); result of assessment [normal bilateral, normal soundfield (better ear) thresholds, unilateral sensorineural, bilateral sensorineural, unilateral conductive, bilateral conductive, mixed bilateral, incomplete]; tympanometry results; hearing thresholds/minimal response levels; probable cause of impairment (if known); end of care (yes/no); and outcome [discharge, referral to ENT, referred for diagnostic confirmation (Cambridge only), hearing aids fitted (Nottingham only)].
Each child’s records were accessed by audiologists authorised to look at them, hence consent was not required from individual patients. Anonymised data were entered onto the database. These procedures received ethical approval. Referral data were checked and corrected for implausible values. Staff time to undertake a planned second data extraction check of 10% was severely restricted by the pressure of service delivery. Undertaking this data check was not possible with the staff resources available without causing a significant delay to the study reporting. Copies of the questionnaires were sent to PenCTU for second data entry and double entry data checking.
Statistical analysis
The yield, rate of referral and age at referral were compared between the site with a SES programme (Nottingham) and the site without a SES programme (Cambridge).
Yield was defined as the number of children between their third and seventh birthdays identified as having hearing impairment whose date of referral was between 1 September 2012 and 30 June 2014 (the study period) per 1000 person-years at risk. Hearing impairment included transient conductive and permanent sensorineural or conductive hearing impairments. The rate of referral was defined as number of referrals for suspected hearing impairment in the same period per 1000 person-years at risk. Some referrals resulted in more than one appointment. Children for whom the outcome of the last appointment was further referral or hearing aid were considered to have hearing impairment and included in the numerator in the calculations for yield; children discharged at the last appointment were considered to have no hearing impairment. In order to calculate the denominator for yield and the referral rate, the population size in each site was obtained from the Office for National Statistics mid-2013 estimates54 of the population who were aged 3, 4, 5 or 6 years in the study sites. The Nottingham site included referrals from the local authorities of Nottingham, Erewash, Ashfield, Broxtowe, Gedling and Rushcliffe; the Cambridge site included Cambridge, East Cambridgeshire and South Cambridgeshire. The number of person-years observed was calculated by multiplying the population size by the number of days during the study period (668 days) and dividing by the mean number of days in a year (365.25 days). The two sites were compared with respect to yield and referral rate using the rate ratio, reported with 95% CI and p-value.
The t-test was used to compare the mean age at referral between the Nottingham and Cambridge sites (1) for all initial referrals; and (2) for confirmed HI cases only.
We report the percentage of referrals that resulted in the identification of HI cases for: (1) Nottingham referrals that were via a school screen; (2) Nottingham referrals that were via any other source (e.g. GP, speech therapist); and (3) Cambridge referrals.
Finally, we report the median (IQR) level of hearing impairment in dB at each of four frequencies (0.5, 1, 2 and 4 kHz) in each ear and the source of referral (using numbers and percentages) for both Nottingham and Cambridge. These variables were summarised for all referrals and then for the subset of referrals that resulted in the identification of children with impaired hearing.
Analyses were carried out using Stata statistical software.
Results
Referral rate and yield
There were 1702 referrals in Nottingham (21.9 referrals per 1000 person-years) and 1108 in Cambridge (34.4 referrals per 1000 person-years); the referral rate in Nottingham was two-thirds that of Cambridge (rate ratio 0.64, 95% CI 0.59 to 0.69; p < 0.001) (). Hearing impairment was confirmed in 195 children in Nottingham (yield of 2.51 cases per 1000 person-years) and 98 children in Cambridge (3.04 cases per 1000 person-years). There was little evidence that the yield is different between Nottingham and Cambridge (rate ratio 0.82, 95% CI 0.64 to 1.06; p = 0.12). Confirmed hearing loss cases made up 17.0% of referred children in Nottingham (25.2% of children who were referred via SES and 14.9% of children referred via other sources) and 10.6% of referred children in Cambridge ().
Comparison of referral and yield rates (as at last appointment) between Nottingham and Cambridge expressed per 1000 children per year
Percentage of referred children who were subsequently confirmed as cases (at last appointment), stratified by site and, for Nottingham, whether or not referral was via SES
The mean age of referral was 4.7 years for both the Nottingham and Cambridge sites, but the mean age at referral for children who were subsequently confirmed as HI was higher in Nottingham than Cambridge (5.0 years vs. 4.5 years; mean difference 0.47 years, 95% CI 0.24 to 0.70 years; p < 0.001) ().
Comparison of the mean age of referral (in years) between Nottingham and Cambridge
The characteristics are summarised in for all referred children and in for children confirmed as HI cases, separately for each of the Nottingham and Cambridge sites. In Nottingham 21.5% of all referrals and 30.8% of the confirmed HI cases were originally referred via SES. Other key sources of referral in Nottingham were ENT consultants (23.6% of confirmed cases), parents (11.8% of confirmed cases), GPs (10.8% of confirmed cases) and health visitors (10.8% of confirmed cases). In the Cambridge site the key sources of referral for confirmed HI cases were GPs (64.3%), health visitors (21.4%) and speech therapist (12.2%).
Characteristics of children referred
Characteristics of confirmed cases of hearing loss
Discussion
It might be expected that adding a screen to a system would result in a greater number of referrals. However, the observational comparison of two sites, one with SES (Nottingham) and one without SES (Cambridge), showed evidence that the rate of referral for hearing problems is lower when SES is present. The referral rate was 36% lower in Nottingham relative to Cambridge (rate ratio 0.64; p < 0.001) and the CI for the rate ratio indicates the true rate is at least 31% lower when there is SES.
In the SES site, one-third of children subsequently confirmed as cases were initially referred via SES. There was little evidence (p = 0.12) that the yield of confirmed cases is altered by SES; the estimated rate of confirmed cases was 18% lower in Nottingham relative to Cambridge but it is plausible within the bounds of the 95% CI that the true yield rate is the same in areas with and without SES. The CI, however, does indicate that it is unlikely that SES areas truly have a markedly higher yield rate. A higher proportion of referred children were subsequently confirmed to be HI in the area with SES (17.0% vs. 10.6%).
The mean age of referral was nearly identical (4.7 years) between the two sites when looking at all referrals. When focusing solely on children who were subsequently confirmed to have a hearing impairment, however, there was strong evidence that the children in the site with a screen were older at referral (5.0 years vs. 4.5 years; p < 0.001). One possibility is that, for children in this age range, parents/professionals in Cambridge seek referral when concerns are raised whereas in the area with SES, if concerns are raised around age 4 years, parents and professionals are aware that SES is coming up later that year and wait.
The CIs for the mean age difference indicates that the true mean age at referral in areas with a screen could plausibly be anywhere between 3 and 8 months greater than areas without one. Delay in identification of a hearing impairment has the potential to adversely affect development1 but further research would be needed to evaluate the extent of the impact for children at school age.
There are also differences in the audiology services operated in the two areas. In Nottingham there is no second-tier audiology service and all referred children are seen within the same service. It has an open referral policy, which includes referrals from parents. It works closely with the ENT department and children move between the two services dependent on their needs. A health professional concerned that a child might have OME and hearing loss has the option to refer for a DEA or to ENT; ENT might then refer for a DEA if appropriate.
The second-tier service in Cambridge accepts referrals from health and education professionals. It provides assessment for children and onward referral for those children who may require hearing aids or surgical management. A health professional with a child with possible OME and hearing loss knows that there is a well-staffed intermediate (DEA) service which can effectively sieve referrals and send those needing ENT examination to ENT departments and those requiring hearing aids to third-tier audiology. Thus GPs will be likely to refer to second-tier audiology and referrals from ENT departments to second-tier audiology will be highly unlikely.
The very different numbers of children referred from different routes are likely to be a function of these different systems in the two areas. Parents can directly refer to the CHAC in Nottingham but in Cambridge they would have to go via a GP (or other professional). GPs in Cambridge would know that they have a second-tier community service which acts as a filter, so would have a tendency to refer there rather than to ENT or third-tier audiology. Hence referrals from ENT to second-tier audiology would be rare in Cambridge, but from ENT to the CHAC would be expected to be higher, as they are. Provision of hearing aids as an outcome is clear in the CHAC, but second-tier audiology services in Cambridge do not provide hearing aids.
Strengths and limitations
Our study had a number of strengths. Data collection in both sites was comprehensive and actively monitored by a senior member of the clinical staff with responsibility for audiological services in each of the two areas. Both were members of the research team. An electronic database used in both sites was developed by staff of PenCTU to standardise data collection.
However, our study design of an observational comparison of two areas [one that operates a SES programme (Nottingham) and the other that does not operate a SES programme (Cambridge)] is subject to major methodological limitations, in spite of our best attempts to choose two sites that were similar to each other. We acknowledge that there may be epidemiological and social differences between the two geographical areas that are likely to confound our findings. Reassuringly, population estimates indicate the proportion of children aged < 16 years to be similar in Nottinghamshire (18.7%) and in Cambridgeshire (18.5%).54 However, the index of socioeconomic deprivation indicates the city of Nottingham (rank 17) to be more deprived on a range of measures than the Cambridge district (rank 188).55 Given the lack of availability of child-level data, we were unable to adjust our analyses to take account of these and other potential confounders. Furthermore, given that we consider only two geographical areas, our results may not be considered as generalisable.
Both sites mainly receive referrals from a defined geographical region but also accept referrals outwith that area. Equally, some children within the defined area may be referred elsewhere; the numbers are estimated to be few by the responsible audiologists. The referral catchment areas also do not exactly match the areas defined by the Office for National Statistics for the population estimates used and there may, therefore, be some minor imprecision in the population denominators used in the analyses.
