An elevated risk of tinnitus may exist among patients with postzoster neuralgia during long-term follow-up compared with matched controls, according to a retrospective population-based cohort study.
Investigators analyzed data from the National Health Insurance Service–National Sample Cohort and used propensity score matching to identify 3,417 patients with postzoster neuralgia and a matched group of controls without the condition on the basis of demographic characteristics and comorbidity history. The primary outcome was a new diagnosis of tinnitus during follow-up through December 2013.
Among the 6,834 total participants, 828 of them developed tinnitus during follow-up, with an incidence rate was nearly 146 cases per 10,000 person-years in the postzoster neuralgia group compared with about 103 cases per 10,000 person-years in the control group. Overall, the patients with postzoster neuralgia had a 1.35 times greater likelihood of developing tinnitus compared with matched controls.
Further, the investigators determined that the risk of tinnitus differed by age group. Compared with patients younger than 40 years, patients aged 40 to 59 years had 1.99 times the risk of tinnitus, and patients aged 60 years or older had 2.37 times the risk of tinnitus during follow-up. Male patients had a lower risk compared with female patients.
Several comorbid conditions were associated with a higher tinnitus risk. For instance, the likelihood of developing tinnitus during the follow-up period was 3.35 times higher among patients with hearing loss, 1.48 times higher among those with sleep disorders, and 1.42 times higher among those with anxiety . Hypertension, diabetes mellitus, chronic kidney disease, and depression weren't associated with statistically significant differences in tinnitus risk following adjustment.
Diagnoses of postzoster neuralgia and tinnitus were identified using International Classification of Diseases, 10th Revision codes within administrative claims data. The propensity score model included age, sex, residential area, economic status, hypertension, diabetes mellitus, chronic kidney disease, hearing loss, depression, anxiety, and sleep disorders.
The investigators noted several limitations, including reliance on diagnostic codes without clinical validation and the absence of data on disease severity, symptom duration, objective clinical parameters, clinician assessments, or audiometric findings. As an observational study, the investigators were unable to establish causality, and residual confounding from unmeasured variables may remain.
“[P]atients with [postzoster neuralgia] have a 35% higher risk of subsequently developing tinnitus compared to [propensity score]–matched controls,” wrote lead study author Cha Dong Yeo, MD, PhD, of the Department of Otorhinolaryngology-Head and Neck Surgery at the Jeonbuk National University College of Medicine in South Korea, and colleagues.
The researchers reported no conflicts of interest.
Source: Medicine