Using a decision-analytic model based on data from Bavarian newborn hearing screening facilities, the cost-effectiveness of tracking newborns with bilateral hearing impairment in Bavaria was assessed. The costs of tracking in Bavaria – that is, €4.55 – compare well with those from a cost analysis of universal newborn hearing screening in Hesse, in which the costs of tracking were estimated at €4.00 . According to a recent literature review , this is the first model to assess the cost-effectiveness of tracking within a newborn hearing screening programme; therefore the results of this model are not directly comparable with those of other models. However, with an ICER of €1,697 per additional detected case of bilateral hearing impairment, the implementation of a tracking system within a newborn hearing screening programme may be cost-effective, in particular with regard to the lifelong benefits of early detection and treatment, such as increased productivity owing to better language outcomes. In the pilot project, it is reported that from 2003 to 2008 there were 51 cases of confirmed bilateral hearing loss detected out of 73,332 infants screened, resulting in a rate of 0.70 per 1,000. That is higher than the rate of 0.51 per 1,000 with tracking used in the model. In the pilot project, 48% of the children with bilateral hearing impairment were followed up solely because of the existence of the tracking centre. Therefore, 27 cases of bilateral hearing impairment would have been diagnosed in the absence of the tracking programme, resulting in a rate of 0.5 per 1,000, compared with 0.31 per 1,000 in the decision-analytic model. However, the incremental number of children detected as a result of tracking is the same: 0.20 per 1,000.
Several economic evaluations have shown that the short-term cost-effectiveness of a newborn hearing screening programme depends not only on the diagnostic accuracy of the screening test procedure, but also on the ability to ensure follow-up of newborns with positive screening test results [20, 26]. Tracking systems are, therefore, needed to ensure that early detection results in early intervention without unnecessary delays. Further studies are needed to evaluate the cost-effectiveness of tracking systems within newborn screening programmes.
The model used here has several limitations. First, it is assumed that, at the end of the four-stage test procedure, bilateral hearing impairment can be definitively confirmed or excluded. However, in contrast to other decision-analytic models which assume conditional independence, it could be considered that the probability that a newborn fails subsequent tests is conditional on having previous positive test results. However, this required the merging of data from two different newborn hearing screening programmes with different referral rates and rates of diagnosis conditional on referral. This merging of data could result in an underestimation of the number of cases detected relative to the experience of both newborn hearing screening programmes.
Second, some of the data used are taken from a Bavarian pilot project, and these data may therefore differ from data compiled subsequent to the nationwide implementation of newborn hearing screening in 2009, as well as data from other newborn hearing screening programmes in Germany. This may have implications for the generalizability of results; however, the issue of generalizability was addressed in the sensitivity analyses.
Third, only parameter and structural uncertainty was addressed via the sensitivity analyses, whereas methodological uncertainty (for example, discount rate, long time horizon) was not addressed, owing to a lack of long-term data. The cost-effectiveness of the intervention in different patient groups (uni- and/or bilateral hearing impairment) was not assessed because the target population was newborns with bilateral hearing impairment only, as is standard practice in Germany . Thus, the analysis is rather conservative. If centralized tracking was extended to include unilateral referrals – some of which may indeed result in the diagnosis of bilateral hearing impairment – the incremental cost-effectiveness ratio would presumably be lower. A recent study found that children with unilateral hearing loss had worse language skills than their siblings with normal hearing . However, more research is needed to clarify this issue.
Fourth, owing to a lack of adequate data, the time horizon was limited to the newborn hearing screening programme (initial hearing screening test and subsequent hearing tests or diagnosis) and a scenario analysis was not conducted.
Several studies have shown that the economic and disease burden of hearing impairment is high. The societal cost of severe to profound hearing loss over the lifetime of an affected person in the United States was estimated at US$297,000, mainly resulting from productivity losses (63%) and the requirement for special education (21%) . Furthermore, permanent bilateral hearing impairment in children between 7 and 9 years of age was found to be associated with reduced health status and health-related quality of life compared with children with normal hearing , and an expected cost to society of about £14,000 in the preceding year of life . Therefore, if a longer time horizon was taken into account, a transsectoral or even societal perspective on the effects on health-related quality of life would favour a newborn hearing screening programme which included tracking. Tracking may even be cost-saving from the perspective of public health services themselves (who pay for the tracking) once public expenditures for schooling etc. for children with special needs are taken into account. However, adequate and robust data on the long-term effects of tracking within newborn screening programmes with respect to costs and outcomes are lacking.