Abstract
IMPORTANCE: Determining the durability of treatment effects extending more that 1 year postintervention is crucial for sustainability of health care services for tinnitus. Tinnitus is often disabling and can result in a considerable economic burden. Identifying tinnitus interventions with stable long-term positive effects can improve health care outcomes. Due to the lack of research focused on outcomes longer than 1 year postintervention, the current study was undertaken. OBJECTIVES: To investigate the durability of treatment effects over a 6-year period following internet-based cognitive behavior therapy (ICBT) for tinnitus. DESIGN, SETTING, AND PARTICIPANTS: In this follow-up of a nonrandomized clinical trial, an online study where participants undertook an internet-based intervention was undertaken. A repeated-measured study design with 6 time points was selected to assess 6-year long-term outcomes of ICBT. Recruitment started January 2016. Participants were those with significant tinnitus who undertook an online tinnitus intervention. Participants from the original trial were invited to partake at 1, 4, 5, and 6 years of follow-up. Assessment of tinnitus distress and associated difficulties regarding anxiety, depression, insomnia, cognitive failures, satisfaction with life, and hearing disability was conducted. Given a delayed intervention group design, the control group had also received the intervention at the 6-year follow-up. There was no active control condition. Analysis was conducted in May to September 2023 and redone in May to July 2025 prior to submission. INTERVENTION: A guided ICBT intervention consisting of 21 modules was presented over 8 weeks. MAIN OUTCOME MEASURES: Reduction in tinnitus distress was the primary outcome together with measuring the secondary outcomes of reductions in anxiety, depression, insomnia, cognitive failures, hyperacusis, hearing disability, and increases with satisfaction with life. RESULTS: Among the 138 from the original trial who were invited to partake at 1, 4, 5, and 6 years of follow-up, 49 participants (35.5%) completed the 6-year postintervention assessment (mean [SD] age, 54.49 (13.29) years; 18 female individuals [37%]; 31 male individuals [63%]). Undertaking ICBT for tinnitus was associated with significant improvements with little variability over the 6-year period, with large within-group effect sizes (eg, Cohen d = 1.00; 95% CI, 0.80-1.32) at 6 years postintervention. Small effects were found on measures of anxiety, depression, insomnia, satisfaction with life, and hyperacusis. At 6-year follow-up clinical significance was obtained by 19 of 49 participants (39%), using the Reliable Change Index (RCI) criterion of a 23.86 points (95% CI, 7.96-39.76) score improvement, and 27 of 49 participants (55%) when using the minimal clinically important difference (MCID) of 14 points (95% CI, 1.9-29.9). When looking at posttreatment results, durability of treatment effects were present for tinnitus distress and measures of anxiety, depression, insomnia, and satisfaction with life, but not for auditory-related effects of hearing disability and hyperacusis. CONCLUSIONS AND RELEVANCE: In this follow-up of a nonrandomized clinical trial, the results indicate potential for informing health care services and reducing health care costs caused by tinnitus over 6 years. The results are significant in indicating ICBT may improve accessibility to evidence-based care and reduce resources required to deliver clinical care. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02370810.