Digging into the Role of Inflammatory Biomarkers in Sudden Sensorineural Hearing Loss Diagnosis and Prognosis: A Systematic Review and Meta-Analysis

Environmental Risk Factors, Protective Factors, and Biomarkers for Hearing Loss: An Umbrella Review

OBJECTIVE

We aimed to investigate the potential environmental risk factors, protective factors, and biomarkers of hearing loss (HL), and establish a hierarchy of evidence.

DATA SOURCES

Embase, PubMed, Cochrane Library, and Web of Science electronic database from inception to June 1, 2023.

REVIEW METHODS

We included meta-analyses of observational studies of associations between HL and environmental risk factors, protective factors, or biomarkers. We calculated summary effect estimates, 95% confidence interval, heterogeneity I2 statistic, 95% prediction interval, small study effects, and excess significance biases.

RESULTS

Of the 9211 articles retrieved, 60 eligible articles were included. The 60 eligible articles identified 47 potential environmental risk and protective factors (N = 4,123,803) and 46 potential biomarkers (N = 173,701). Evidence of association was convincing (class I) for rheumatoid arthritis (RA) and every 1 cm increase in height. Evidence of association was highly suggestive (class II) for human immunodeficiency virus (HIV), diabetes, cumulative noise exposure (CNE), smoking, congenital cytomegalovirus (CMV) infection, combined exposure to organic solvents and noise, non-Gaussian noise exposure, each 1 kg increase in birth weight, noise exposure, and alopecia areata (AA).

CONCLUSION

In this umbrella review, RA, every 1 cm increase in height, HIV, diabetes, CNE, smoking, congenital CMV infection, combined exposure to organic solvents and noise, non-Gaussian noise exposure, each 1 kg increase in birth weight, noise exposure, and AA were strongly associated with HL.

A Comprehensive Study on Sudden Deafness for Analyzing Their Clinical Characteristics and Prognostic Factors

Background: To study the factors associated with the prognosis of patients with sudden deafness to facilitate clinical treatment and improve efficacy. Methods: A total of 414 patients with sudden deafness treated in Zhenjiang First People's Hospital from January 2020 to December 2022 were chosen. Relevant data were gathered and the effectiveness of treatment was assessed by comparing hearing test results before and after hospital admission and divided into effective and ineffective groups, and the effectiveness of each factor was analyzed using univariate analysis, Spearman's correlation analysis, and multifactor logistic regression. Results: The 2 groups had significant differences in age, presence of tinnitus, degree of hearing loss, and triglyceride levels. Spearman's rank correlation analysis showed a negative correlation between hearing threshold of at least 81 dB at 250 to 8000 Hz, the low-density lipoprotein (LDL), triglyceride levels, and the prognosis (r < 0, P < .001). A positive correlation exists between high-density lipoprotein levels and prognosis (r > 0, P < .001). Receiver operating characteristic curve showed LDL level, age, and time since disease onset appears to be highly predictive. Multivariable logistic regression analysis showed that age >47 years, LDL >2.93 mmol/L, and time to presentation >10 days after disease onset are at higher risk for poor prognosis. Conclusion: Factors that influence the prognosis of patients with sudden deafness include age, tinnitus symptoms, high LDL levels, and the type of hearing curve. Early intervention and targeted treatment should be given to high-risk patients to improve the outcome of sudden deafness in clinical practice.

Associations between neutrophil-to-lymphocyte/platelet-to-lymphocyte and recovery in sudden sensorineural hearing loss

Aims: This study investigated the nonlinear associations between neutrophil-to-lymphocyte (NLR)/platelet-to-lymphocyte (PLR) and recovery rates in sudden sensorineural hearing loss (SSNHL). Methods: Total of 244 SSNHL patients were included. The primary outcome was recovery rate. Results: A nonlinear association was detected between NLR and recovery rate using the LOWESS method, with a knot of 3. Patients with NLR ≥3 had a higher recovery rate than NLR <3. Using the linear-spline function, NLR was significantly associated with high recovery rate when NLR was <3. However, when NLR was ≥3, this association became nonsignificant. The trend test showed a similar result. PLR was not associated with recovery rate. Conclusion: The association between NLR and recovery rate is nonlinear, with a knot of around three. PLR is not associated with recovery rate.

Comparison of Batroxobin Versus the Combination of Batroxobin and Intratympanic Dexamethasone Injection in the Treatment of Sudden Sensorineural Hearing Loss

Introduction: Sudden sensorineural hearing loss (SSNHL) manifests as an abrupt decline in hearing by at least 30 dB within a 3 day period. Intratympanic dexamethasone injection (ITDI) has gained recognition as a potential treatment for SSNHL. This study aims to investigate the efficacy of combining batroxobin with ITDI (Bat and ITDI) in treating SSNHL patients and its influence on peripheral blood inflammatory indicators. Methods: SSNHL patients were retrospectively categorized into the control group (treated with Bat) and the observation group (treated with Bat and ITDI). The study involved analyzing clinical baseline data, evaluating clinical efficacy, and comparing the total effective rates among SSNHL patients with different audiometric curve types in the observation group. Routine blood tests were performed on peripheral blood samples to calculate the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), and to determine C-reactive protein (CRP) levels. Adverse reactions and complications were closely monitored. Results: Following treatment, both groups displayed improvements in hearing, with the observation group exhibiting a significantly higher total effective rate (75.90%) than the control group (59.78%). For patients with 3 distinct types of sudden hearing loss (high-frequency, flat-frequency, total deafness), Bat and ITDI treatment demonstrated increased total effective rate for patients with different sudden hearing loss types (high-frequency, flat-frequency, and total deafness). Both groups experienced reduced peripheral blood CRP levels and the NLR/PLR values, with the observation group demonstrating lower values. Additionally, across the 4 audio metric subtypes, the levels of peripheral blood CRP, NLR, and PLR decreased in SSNHL patients, and the observation group had a lower incidence of adverse reactions compared to the control group. Conclusions: Bat and ITDI emerge as notably more effective for SSNHL patients, displaying potential for reducing peripheral blood inflammatory indicator levels and mitigating the incidence of adverse reactions or complications, thereby enhancing safety.

Association between hearing loss and high-sensitivity C-reactive protein: the Kangbuk Samsung Cohort Study

Background

Hearing loss (HL) is linked to an elevated risk of cardiovascular diseases (CVDs). The pathogeneses of HL and CVD commonly involve inflammatory responses. Previous studies investigated elevated levels of inflammatory biomarkers in subjects with HL, however, their findings did not demonstrate statistical significance. In our cross-sectional and longitudinal study, we investigated the correlation between HL and increased high-sensitivity C-reactive protein (hsCRP) levels to determine how HL is associated with CVDs.

Methods

We conducted a cross-sectional study with workers aged over 18 years who underwent health check-ups at our institution between 2012 and 2018 (n = 566,507), followed by conducting a longitudinal study of workers aged > 18 who underwent health checkups at least twice at our institution between 2012 and 2018 (n = 173,794). The definition of HL was as an average threshold of ≥ 20 dB in pure-tone air conduction at 0.5, 1.0, and 2.0 kHz in both ears. The incidence of increased hsCRP levels throughout the follow-up period was defined as a level exceeding 3 mg/L. Logistic regression and generalized estimating equations were performed to estimate the risk of increased hsCRP levels according to the occurrence of HL in groups stratified by age.

Results

In the cross-sectional study, the multivariate-adjusted odds ratio (OR) was 1.17 (95% confidence interval [CI]: 1.02-1.34); the OR was 0.99 (95% CI: 0.80-1.22) in those under 40 and 1.28 (1.08-1.53) in those over 40. In the longitudinal study, the multivariable-adjusted OR was 1.05 (95% CI: 0.92-1.19); the OR was 1.10 (95% CI: 0.90-1.35) in those under 40 and 1.20 (1.01-1.43) in those over 40.

Conclusions

This cross-sectional and longitudinal study identified an association between HL and increased hsCRP levels in workers aged over 40 years.

The prognostic value of peripheral blood parameters on all-frequency sudden sensorineural hearing loss

OBJECTIVE

To determine whether peripheral blood parameters have any predictive value for all-frequency Sudden Sensorineural Hearing Loss (SSNHL).

METHODS

We chose 78 individuals with all-frequency SSNHL who had been admitted to our department. They were divided into two groups: the effective group and the ineffective group. In patients with all-frequency SSNHL, the prognostic variables, including peripheral blood tests and clinical traits, were examined by a logistic regression analysis. In addition, the predictive value was carried out.

RESULTS

The effective rate of all-frequency SSNHL was 61.5%. Pre-treatment hearing level and the proportion of patients with diabetes were both significantly lower in the effective group than in the ineffective group (p = 0.024 and 0.000, respectively). The levels of fibrinogen and C-reactive protein were also significantly different between the two groups (p = 0.001 and 0.025, respectively). Pre-treatment hearing level and fibrinogen level both significantly impacted the prognosis of all-frequency SSNHL (p = 0.032 and 0.002, respectively), according to a logistic regression analysis. Furthermore, the prognosis was significantly predicted by both fibrinogen level and pre-treatment hearing level (p = 0.001 and 0.0002, respectively). The receiver operating characteristic curve showed that the fibrinogen level had a sensitivity of 85.4% and a specificity of 60.0% for predicting the prognosis of all-frequency SSNHL.

CONCLUSION

For the prognosis of all-frequency SSNHL, the fibrinogen level can be regarded as a useful predictor. The level of C-reactive protein, however, does not have a significant prognostic effect on predicting all-frequency SSNHL. Therefore, more attention should be devoted to the level of fibrinogen in the acute period of all-frequency SSNHL.

LEVEL OF EVIDENCE: 4

Vertebrobasilar and Basilar Dolichoectasia Causing Audio-Vestibular Manifestations: A Case Series with a Brief Literature Review

Audio-vestibular symptoms can arise from vertebrobasilar dolichoectasia (VBD) and basilar dolichoectasia (BD). Given the dearth of available information, herein we reported our experience with different audio-vestibular disorders (AVDs) observed in a case series of VBD patients. Furthermore, a literature review analyzed the possible relationships between epidemiological, clinical, and neuroradiological findings and audiological prognosis. The electronic archive of our audiological tertiary referral center was screened. All identified patients had a diagnosis of VBD/BD according to Smoker's criteria and a comprehensive audiological evaluation. PubMed and Scopus databases were searched for inherent papers published from 1 January 2000 to 1 March 2023. Three subjects were found; all of them had high blood pressure, and only the patient with high-grade VBD showed progressive sensorineural hearing loss (SNHL). Seven original studies were retrieved from the literature, overall including 90 cases. AVDs were more common in males and present in late adulthood (mean age 65 years, range 37-71), with symptoms including progressive and sudden SNHL, tinnitus, and vertigo. Diagnosis was made using different audiological and vestibular tests and cerebral MRI. Management was hearing aid fitting and long-term follow-up, with only one case of microvascular decompression surgery. The mechanism by which VBD and BD can cause AVD is debated, with the main hypothesis being VIII cranial nerve compression and vascular impairment. Our reported cases suggested the possibility of central auditory dysfunction of retro-cochlear origin due to VBD, followed by rapidly progressing SNHL and/or unnoticed sudden SNHL. More research is needed to better understand this audiological entity and achieve an evidence-based effective treatment.

Comparison of Intratympanic Steroid and Hyperbaric Oxygen Salvage Therapy Hearing Outcomes in Idiopathic Sudden Sensorineural Hearing Loss: A Retrospective Study

OBJECTIVES

Systemic steroids are the most common first-line therapy in sudden sensorineural hearing loss (SSNHL), with significant improvement in hearing outcomes in over 60% of patients. It is unknown why 40% of patients do not respond to systemic steroid therapy. Salvage treatment includes intratympanic steroids (ITS) and hyperbaric oxygenation (HBO) therapy, with inconsistent results reported. This study aimed to compare the results of ITS and HBO therapy in patients with SSNHL that previously failed systemic steroid therapy.

DESIGN

This is a comparative retrospective nonrandomized interventional cohort study, enrolling 126 patients with SSNHL. Out of these, 35 patients received HBO therapy, 43 patients received ITS, and 48 patients did not receive any second-line therapy (control group). Pure-tone audiograms were performed before and after the salvage therapy in the IT and HBO groups and at the same time interval in the control group. Study variables included age, time until therapy initiation, tinnitus status, and hearing outcomes, with a cutoff criteria of cumulative >30 dB improvement on all frequencies indicating recovery.

RESULTS

ITS and HBO therapy were associated with statistically significant hearing recovery at all frequencies compared to systemic steroids. The results show an average hearing improvement of 13.6 dB overall frequencies (250 to 8000 Hz) after ITS therapy and 7.4 dB in HBO therapy in comparison to the control group. Presence of significant hearing improvement positively correlated with age, ITS therapy, and HBO therapy. Presence of tinnitus before therapy was negatively correlated with hearing improvement. Patients with tinnitus present at the start of therapy improve 4.67 dB less on average compared to those without tinnitus. ITS therapy significantly reduced tinnitus compared to the other two treatment options. Patients with tinnitus present before therapy significantly improve hearing at low frequencies, compared to the control group.

CONCLUSIONS

ITS and HBO therapy show superior hearing results compared to observation alone after failed oral steroid therapy for SSNHL. ITS shows an additional positive impact on tinnitus reduction and shows superior hearing outcomes after salvage therapy.

Inflammatory markers and the risk of idiopathic sudden sensorineural hearing loss: A Mendelian randomization study

Background

Observational studies suggest that inflammatory markers may increase the risk of idiopathic sudden sensorineural hearing loss (ISSHL). However, the causal relationship between the two has not been established. We sought to assess the possible causal effect between several genetically predicted inflammatory markers and ISSHL by Mendelian random (MR) analysis.

Methods

We extracted single nucleotide polymorphisms (SNPs) associated with C-reactive protein (CRP), Tumor necrosis factor-α (TNF-α), and fibrinogen from abstract data from the European Individual Large genome-wide association studies (GWAS). Genetic data for ISSHL were obtained from the FinnGen study (n = 196,592). Effect estimates were assessed using inverse variance weighting (IVW) as the primary method. Sensitivity analyses were performed using weighted median, MR-Egger, and MR-PRESSO to evaluate heterogeneity and pleiotropy.

Results

In the random-effects IVW approach, there was a significant causal relationship between genetic susceptibility to CRP levels and ISSHL (OR = 1.23, 95% CI = 1.02-1.49, P = 0.03). In contrast, genetic TNF-α and fibrinogen were not risked factors for ISSHL (OR = 1.14, 95% CI = 0.88-1.49, P = 0.30; OR = 0.74, 95% CI = 0.07-7.96, P = 0.30; OR = 1.05, 95% CI = 0.88-1.25, P = 0.59). All the above results were consistent after validation by different Mendelian randomization methods and sensitivity analyses.

Conclusion

This Mendelian randomization study provides causal evidence that CRP is a risk factor for ISSHL, while TNF-α and fibrinogen do not increase the risk for ISSHL Introduction.