Innovations in Doctoral Training and Research on Tinnitus: The European School on Interdisciplinary Tinnitus Research (ESIT) Perspective

Background There is no evidence-based guidance to facilitate design decisions for confirmatory trials or systematic reviews investigating treatment efficacy for adults with tinnitus. This systematic review therefore seeks to ascertain the current status of trial designs by identifying and evaluating the reporting of outcome domains and instruments in the treatment of adults with tinnitus. Methods Records were identified by searching PubMed, EMBASE CINAHL, EBSCO, and CENTRAL clinical trial registries (ClinicalTrials.gov, ISRCTN, ICTRP) and the Cochrane Database of Systematic Reviews. Eligible records were those published from 1 July 2006 to 12 March 2015. Included studies were those reporting adults aged 18 years or older who reported tinnitus as a primary complaint, and who were enrolled into a randomised controlled trial, a before and after study, a non-randomised controlled trial, a case-controlled study or a cohort study, and written in English. Studies with fewer than 20 participants were excluded. Results Two hundred and twenty-eight studies were included. Thirty-five different primary outcome domains were identified spanning seven categories (tinnitus percept, impact of tinnitus, co-occurring complaints, quality of life, body structures and function, treatment-related outcomes and unclear or not specified). Over half the studies (55 %) did not clearly define the complaint of interest. Tinnitus loudness was the domain most often reported (14 %), followed by tinnitus distress (7 %). Seventy-eight different primary outcome instruments were identified. Instruments assessing multiple attributes of the impact of tinnitus were most common (34 %). Overall, 24 different patient-reported tools were used, predominantly the Tinnitus Handicap Inventory (15 %). Loudness was measured in diverse ways including a numerical rating scale (8 %), loudness matching (4 %), minimum masking level (1 %) and loudness discomfort level (1 %). Ten percent of studies did not clearly report the instrument used. Conclusions Our findings indicate poor appreciation of the basic principles of good trial design, particularly the importance of specifying what aspect of therapeutic benefit is the main outcome. No single outcome was reported in all studies and there was a broad diversity of outcome instruments. PROSPERO registration The systematic review protocol is registered on PROSPERO (International Prospective Register of Systematic Reviews): CRD42015017525. Registered on 12 March 2015 revised on 15 March 2016. Electronic supplementary material The online version of this article (doi:10.1186/s13063-016-1399-9) contains supplementary material, which is available to authorized users.

Tinnitus is described as the perception of sound or noise in the absence of real acoustic stimulation. In the current absence of a cure for tinnitus, clinical management typically focuses on reducing the effects of co-morbid symptoms such as distress or hearing loss. Hearing loss is commonly co-morbid with tinnitus and so logic implies that amplification of external sounds by hearing aids will reduce perception of the tinnitus sound and the distress associated with it.

The aim of this study was to examine the costs of tinnitus in The Netherlands from a health care and a societal perspective. Furthermore, the impact of disease characteristics and demographic characteristics on these costs were examined. A bottom-up cost of illness study was performed, using the baseline data on a cost questionnaire of a randomized controlled trial investigating the (cost) effectiveness of an integral multidisciplinary treatment for tinnitus versus care as usual. Mean yearly costs were multiplied by the prevalence figure of tinnitus for the adult general population to estimate the total cost of illness of tinnitus to society. Because cost data usually are not normally distributed, a nonparametric bootstrap resampling procedure with 1000 simulations was performed to determine statistical uncertainty of the cost estimates per category. Several questionnaires measuring disease and demographic characteristics were administered. The impact of disease characteristics and demographics on costs was investigated using a multivariate regression analysis. Total mean societal cost of illness was €6.8 billion (95% confidence interval: €3.9 billion-€10.8 billion). The larger part of total cost of illness was not related to health care. Total mean health care costs were €1.9 billion (95% confidence interval: €1.4 billion-€2.5 billion). Significant predictors of both health care costs and societal costs were tinnitus severity, age, shorter duration of tinnitus, and more severe depression. The economical burden of tinnitus to society is substantial, and severity of tinnitus is an important predictor of the costs made by patients.