The objective was to assess the cost-effectiveness of early screening for hearing loss in older adults. The authors concluded that the most cost-effective strategy was audiometric screening for bilateral hearing loss, at a level of at least 30 decibels, starting at age 60 years. The methods appear to have been appropriate, but the validity of some estimates was unclear due to a lack of reporting. The limitations outlined should be considered when interpreting the results.

Cost-utility analysis

The objective was to assess the cost-effectiveness of early screening for hearing loss in older adults.

A one-stage and a two-stage screening strategy were considered. The one-stage strategy was a test to identify hearing levels of 35 decibels (dB) or worse, using a standard clinical audiometer. The two-stage strategy was a postal questionnaire to identify individuals with hearing difficulties, who were then assessed using pure tone audiometry (PTA), which was assumed to be the gold standard for testing. Screening started at age 60 years, and was repeated at 65 and 70 years.

The comparator was usual care, defined as the existing general practitioner (GP) referral service. This required adults to request an appointment with their GP, and for their GP to refer them for audio testing, using PTA.

UK/primary care.

Analytical approach:

A Markov model was developed to assess the costs and outcomes, for each strategy, using a cohort of 100,000 adults aged 60 years, from the general population. The time horizon was 25 years (from 60 to 85 years). The authors stated that the analysis was conducted from a UK NHS perspective.

Effectiveness data:

The strategies were selected based on the findings of a recent National Institute for Health Research, Health Technology Assessment (HTA; see Other Publications of Related Interest). This found that screening was acceptable and beneficial, and the most appropriate strategy was to screen 60-year-olds for bilateral healing loss of at least 35dB. The key effectiveness data were the sensitivity, specificity and acceptance rates for the alternative strategies. Most of these data were from the HTA report, including the sensitivity and specificity of testing, and the prevalence, acceptance rates, and probability of using a hearing aid. Extensive literature searches were conducted, to obtain the input parameters, to supplement the data from the HTA report.

Monetary benefit and utility valuations:

A utility gain was applied to all participants in the model who accepted the offer of a hearing aid. This was the same for all strategies and scenarios (0.068), and was based on the HTA report and another published study.

Measure of benefit:

The health benefit was measured using quality-adjusted life-years (QALYs). Future benefits were discounted at an annual rate of 3.5%.

Cost data:

The costs of screening, hearing assessments, hearing aid fitting and repair, and follow-up appointments were included. Screening costs were based on estimates from the HTA report. All other costs were from the UK 2009 to 2010 Audit Hearing Services Indicative Tariff. Future costs were discounted at an annual rate of 3.5%.

Analysis of uncertainty:

One-way and probabilistic sensitivity analyses were conducted to assess the impact of individual and joint parameter uncertainty on the model results. The probabilistic analysis results were presented as a cost-effectiveness acceptability curve of the likelihood that each strategy was cost-effective, over a range of willingness-to-pay thresholds. Several scenario analysis were presented, including an analysis of screening for bilateral hearing loss of 30dB or worse (a higher level).

An incremental analysis was presented. In the main analysis, GP referral (usual care) resulted in 10,048 QALYs at a cost of £13,176,794; two-stage screening resulted in 13,768 QALYs at cost of £20,088,732; and one-stage screening resulted in 14,957 QALYs at a cost of £21,947,434.

The two-stage strategy was extendedly dominated, as a more effective strategy had a lower cost per unit of benefit. The one-stage strategy had an incremental cost-effectiveness ratio of £1,787 per QALY gained, compared with GP referral; and a 95% likelihood of being cost-effective at a willingness-to-pay threshold of £12,000 per QALY.

Considering all screening scenarios, all strategies were extendedly dominated, except for one-stage screening for bilateral hearing loss at a level of at least 30dB from age 60 years; this had an incremental cost-effectiveness ratio of £1,461 per QALY gained, compared with GP referral.

The one-way sensitivity analysis showed that the results were sensitive to variations in the estimate of utility with hearing aids.

The authors concluded that the most cost-effective strategy was audiometric screening for bilateral hearing loss at a level of at least 30dB, starting at age 60 years.

Interventions:

The interventions and comparator were clearly described. The comparator, usual care, was appropriate. The authors considered those strategies that were identified in the HTA report as having the best test properties, from a range of one- and two-stage processes; they acknowledged that other options might be available.

Effectiveness/benefits:

The effectiveness and utility estimates were clearly reported, in a table, for the main analysis. The parameter values, for the alternative scenarios, were reported in an online appendix. A review was conducted to identify these estimates, but few methods were reported, making an assessment of its quality impossible. Limited details about the effectiveness data were presented. The model was most sensitive to the utility data, but how these data were measured, valued, and combined from the two source studies, were not reported. The authors highlighted the limitations in the data, and the lack of robust estimates for some of the model parameters. These limitations, with the lack of reporting on the utilities, make the inputs uncertain.

Costs:

The cost estimates were clearly reported for the main analysis. All the relevant costs were included and appropriate sources were used. The authors did not explicitly state the price year, but they appear to have used 2009 to 2010 prices. Future costs and benefits were appropriately discounted. The authors acknowledged that the costs of audiology appointments could have been underestimated, as the model screened every five years, but recommended UK practice was to screen every three years. As this applied to all the scenarios, it should not significantly affect the results. It was clearly stated that the costs of setting up the screening programmes were not included. This might be reasonable in some circumstances, but a decision maker would want to consider these costs before deciding which strategy to implement.

Analysis and results:

The model was clearly described, with a diagram. The time horizon was sufficient to capture the differences between the strategies. The results of the main analysis were fully reported. Since the authors concluded that one of the alternative scenarios was most cost-effective, it would have been useful to see those results in full. Appropriate sensitivity analyses were conducted to assess the impact of parameter uncertainty on the results. The ranges and distributions used were clearly reported and appear to have been appropriate. The results of the probabilistic sensitivity analysis were clearly reported, but not all the results of the one-way sensitivity analyses were given. The authors carefully considered the limitations of their analysis, which mainly related to a lack of available data. They noted that if a screening programme was being considered, it would be necessary to conduct an economic evaluation at the same time.

Concluding remarks:

The methods appear to have been appropriate. There was a lack of reporting, which made the validity of the effectiveness and utility estimates unclear. These limitations should be considered when interpreting the results.

Not stated.

Davis A, Smith P, Ferguson M, et al. Acceptability, benefit and costs of early screening for hearing disability: a study of potential screening tests and methods. Health Technology Assessment 2007; 11(42): 1-294.