AUTHOR=Lin Herng-Ching , Xirasagar Sudha , Wang Chia-Hui , Cheng Yen-Fu , Yang Tzong-Hann 

TITLE=Increased Risk of Major Depressive Disorder Following Tinnitus: A Population-Based Study

JOURNAL=Frontiers in Neurology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.836842

DOI=10.3389/fneur.2022.836842

ISSN=1664-2295

ABSTRACT=Background and purpose: In this study we aimed to evaluate the relationship between tinnitus and a subsequent diagnosis of major depressive disorder (MDD) by studying the incidence of both entities. 
Design: A retrospective cohort study
Methods: Data for this observational follow-up study were retrieved from the Taiwan’s National Health Insurance Dataset. A total of 375,272 patients with newly diagnosed tinnitus (study group) were retrieved. The date of first diagnosis of tinnitus was assigned as their index date. Comparison patients were selected by propensity score-matching (one per case, n=375,272 controls) from the same dataset, with their index date being the date of their first health service claim in the year of diagnosis of their matched index case. We tracked each patients claims records for one year from the index date to identify those who received a diagnosis of MDD. Cox proportional hazards regression was performed to calculate the MDD hazard ratio for cases vs. controls.
Results: We found that the overall incidence rate for MDD was 0.78 (95% CI=0.76~0.80) per 100 person-years, being 1.17 (95% CI=1.14~1.21) among the study cohort and 0.38 (95% CI=0.36~0.40) among the comparison cohort. The log-rank test revealed that patients in the study cohort had significantly lower one-year MDD-free survival when compared to the comparison cohort (p<0.001). Cox proportional hazards analysis showed that patients in the study cohort had higher hazard of developing MDD than patients in the comparison cohort (adjusted HR=3.08, 95% CI=2.90~3.27). 
Conclusions: In this study we demonstrate that tinnitus is associated with increased hazard of subsequent MDD in Taiwan.