CRD summary

This review concluded that hearing aids improve the health-related quality of life of adults. The quantity and quality of the included studies was limited, and some aspects of the review process were not reported. Despite this, the conclusions are likely to be reliable since the direction of effect was similar across studies, with larger effects reported in the better quality studies.

Authors' objectives

To evaluate the effect of hearing aids on health-related quality of life (HRQoL) in adults with sensorineural hearing loss (SNHL).

Searching

ComDisDome was searched from 1980, and CINAHL, EBM Reviews, the Cochrane CENTRAL Register and the Cochrane Database of Systematic Reviews from 1996 to July 2004; the search terms were reported. Only studies reported in the English language were included.

Study selection

Assessment of study quality

Study quality was assessed in terms of the use of a control group and power calculations, comparability at baseline, details of the inclusion and exclusion criteria, the fit of the hearing aid and verification, statistics used, and the reporting of drop-outs. The authors did not state how many reviewers performed the quality assessment.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction. Changes in HRQoL scores after treatment or difference compared with the control were extracted from each study, and Cohen’s d and 95% confidence intervals (CIs) calculated for each outcome measure reported. Funnel plots were used to evaluate publication bias.

Methods of synthesis

Results of the review

Sixteen studies (n=1,557) were included in the review: 2 RCTs, 5 quasi-experimental studies, 1 correlational study and 8 pre-test post-test studies.

Three studies used a control group, 12 reported adequate details of the inclusion and exclusion criteria, 9 reported on hearing aid fit and/or verification of fit, and one on the use of a power calculation. All 16 studies used appropriate statistical analyses. Where applicable, all studies had groups comparable at baseline, and 50% discussed drop-outs. The authors stated that there was no evidence of publication bias in the review.

Generic HRQoL instruments: the mean ES from RCTs and quasi-randomised trials was 0.28 (95% CI: 0.09, 0.48), and 0.02 (95% CI: -0.04, 0.07) when observational studies were included.

Disease-specific HRQoL instruments: the mean ES from RCTs and quasi-randomised trials was 2.07 (95% CI: 0.51, 3.63), and 1.01 (95% CI: 0.76, 1.26) from observational studies.

Cohen’s d values and 95% CIs were provided for each domain of the EQ-5D and MOS SF-36 HRQoL measures from the 3 studies that reported them.

Authors' conclusions

Hearing aids improve adults’ HRQoL by reducing the psychological, social and emotional effects of SNHL.

CRD commentary

The review addressed a clear research question, with clearly defined inclusion criteria. Several relevant sources were searched, thereby reducing the potential for publication bias. However, only English language studies were included, therefore there is a potential for language bias. Although the study selection was conducted in duplicate, it was not clear whether similar methods to reduce error and bias were employed during the data extraction and quality assessment phases. The included studies did not include people with profound hearing loss, therefore the results may not be generalisable to that group. The authors did not investigate heterogeneity between the studies, stating that a random-effects meta-analysis negated the need for this. There were limitations to the evidence available in terms of both the numbers of studies evaluating each HRQoL measure and the quality of the included studies. Despite this, and the lack of reporting of some of the review methodology, the conclusions are likely to be reliable since most of the studies reported the same direction of effect, with the larger effects from better quality studies.

Implications of the review for practice and research

Practice: The authors did not report any implications for practice.

Research: The authors suggested that future studies should use an RCT design, include a heterogeneous population, focus on the effect of hearing aid treatment on generic HRQoL, use new outcome measures that are sensitive to the consequences of hearing loss and interventions to treat it, and derive contextually appropriate benchmarks to use in audiologic treatment.

Funding

American Academy of Audiology.

Bibliographic details

Chisolm T H, Johnson C E, Danhauer J L, Portz L J, Abrams H B, Lesner S, McCarthy P A, Newman C W. A systematic review of health-related quality of life hearing aids: final report of the American Academy of Audiology Task Force on the Health-Related Quality of Life Benefits of Amplication in Adults. Journal of the American Academy of Audiology 2007; 18(2): 151-183. [PubMed: 17402301]

Indexing Status

Subject indexing assigned by NLM

MeSH

Advisory Committees /organization & administration; Audiology; Health Status; Hearing Aids; Hearing Disorders /therapy; Humans; Patient Satisfaction; Practice Guidelines as Topic; Quality of Life /psychology; United States

AccessionNumber

12007001399

Database entry date

30/09/2008

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.