The atherogenic index (ATH index) as a potential predictive marker of idiopathic sudden sensorineural hearing loss: a case control study

Traditional and non-traditional lipid parameters as risk factors for sudden sensorineural hearing loss

OBJECTIVE

The purpose was to explore the effects of traditional and non-traditional lipid parameters on Sudden Sensorineural Hearing Loss (SSNHL).

METHODS

The study included 452 patients diagnosed with SSNHL, among whom 206 patients had a level of hearing improvement ≥10 dB after one month of follow-up. A propensity score-matched (2:1) control group was used. Conditional and unconditional logistic regression were used to analyze the risk factors for SSNHL.

RESULTS

Patients with SSNHL had a higher risk of concomitant hypertension and elevated atherosclerogenic lipid levels, with apolipoprotein B and apolipoprotein E identified as independent risk factors for the onset of SSNHL. Additionally, the Lipid Comprehensive Index (LCI) was an independent risk factor for the degree of hearing loss. A positive linear correlation was revealed between triglyceride, non-high-density lipoprotein cholesterol, atherogenic index, Castelli risk index, atherogenic index of plasma, LCI and hearing loss. However, no linear relationship was observed between hearing gain and any lipid parameters. When Total Cholesterol (TC) was in the range of borderline high, the treatment effect was the best. However, the statistical significance disappeared upon adjusting for confounding factors.

CONCLUSION

Patients with SSNHL exhibited markedly dysregulated lipid metabolism. Elevated serum lipid levels may be a causative factor in auditory impairment and can influence the extent of hearing loss. Promptly improving cochlear microcirculation may benefit patients with borderline elevated TC.

LEVEL OF EVIDENCE: 4

The Impact of Cardiovascular Risk Factors on the Incidence, Severity, and Prognosis of Sudden Sensorineural Hearing Loss (SSHL): A Systematic Review

Sudden sensorineural hearing loss (SSHL) is believed to be mainly idiopathic since the cause is not usually identified. Several recent studies have examined the role of cardiovascular risk factors in this disease. The aim of this systematic literature review is to investigate the possible association between acquired and inherited cardiovascular risk factors and the incidence, severity, and prognosis of SSHL. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of the PubMed database for the period between February 2010 and January 2023 was performed in order to retrieve eligible articles. The analytic cohort included 24 studies. Overall, this systematic review includes a total of 61,060 patients that were encompassed in these studies. According to most studies, the prevalence of dyslipidaemia, diabetes, and ultrasound indices of atherosclerosis was significantly higher in SSHL patients compared to controls. On the other hand, obesity, hypertension, and smoking did not seem to influence the risk of SSHL. Most studies suggest the presence of a correlation between a high cardiovascular risk profile and the risk of developing SSHL. The theory of microvascular impairment in the development of SSHL is indirectly supported by the findings of this review.

L-shaped association of triglyceride glucose index and sensorineural hearing loss: results from a cross-sectional study and Mendelian randomization analysis

Background

The association between the sensorineural hearing loss (SNHL) and triglyceride-glucose (TyG) index remains inadequately understood. This investigation seeks to elucidate the connection between the TyG index and SNHL.

Methods

In this cross-sectional study, we utilized datasets sourced from the National Health and Nutrition Examination Survey (NHANES). A comprehensive analysis was conducted on 1,851 participants aged 20 to 69, utilizing complete audiometry data from the NHANES database spanning from 2007 to 2018. All enrolled participants had accessible hearing data, and the average thresholds were measured and calculated as both low-frequency pure-tone average and high-frequency pure-tone average. Sensorineural hearing loss (SNHL) was defined as an average pure tone of 20 dB or higher in at least one better ear. Our analysis involved the application of multivariate linear regression models to examine the linear relationship between the TyG index and SNHL. To delineate any non-linear associations, we utilized fitted smoothing curves and conducted threshold effect analysis. Furthermore, we conducted a two-sample Mendelian randomization (MR) study, leveraging genetic data from genome-wide association studies (GWAS) on circulating lipids, blood glucose, and SNHL. The primary analytical method for the MR study was the application of the inverse-variance-weighted (IVW) approach.

Results

In our multivariate linear regression analysis, a substantial positive correlation emerged between the TyG index and SNHL [2.10 (1.80-2.44), p < 0.0001]. Furthermore, using a two-segment linear regression model, we found an L-shaped relationship between TyG index, fasting blood glucose and SNHL with an inflection point of 9.07 and 94 mg/dL, respectively. Specifically, TyG index [3.60, (1.42-9.14)] and blood glucose [1.01, (1.00-1.01)] concentration higher than the threshold values was positively associated with SNHL risk. Genetically determined triglyceride levels demonstrated a causal impact on SNHL (OR = 1.092, p = 8.006 × 10-4). In addition, blood glucose was found to have a protective effect on SNHL (OR = 0.886, p = 1.012 × 10-2).

Conclusions

An L-shaped association was identified among the TyG index, fasting blood glucose, and SNHL in the American population. TyG index of more than 9.07 and blood glucose of more than 94 mg/dL were significantly and positively associated with SNHL risk, respectively.

Cardiovascular Risk Factors, Cerebral Small Vessel Disease, and Subsequent Risk of Stroke in Patients with Idiopathic Sudden Sensorineural Hearing Loss: Systematic Review and Meta-Analyses of the Current Literature

Vascular involvement in the pathophysiology of idiopathic sudden sensorineural hearing loss (iSSNHL) has been previously proposed. The objective of this study was to perform a systematic review of the current literature and conduct meta-analyses to evaluate associations between cardiovascular risk factors, cerebral small vessel disease, and subsequent stroke after presentation with iSSNHL. Three systematic literature reviews and meta-analyses were conducted using PubMed, Embase, and CINAHL. All studies investigating associations between iSSNHL and the cardiovascular risk factors: body mass index (BMI), diabetes mellitus, hyperlipidemia, hypertension, medical history of myocardial infarction (MI), smoking, the degree of white matter hyperintensities, and incidence of stroke were included. Adhering to the PRISMA guidelines, two independent reviewers reviewed the articles and assessed risk of bias. The cardiovascular risk factors of abnormal BMI, diabetes, hypertension, total cholesterol, low-density lipoprotein cholesterol, and a medical history of MI were significantly associated with iSSNHL. The adjusted hazard ratio of a higher degree of white matter hyperintensities was 0.70 (95% CI 0.44, 1.12). Patients with iSSNHL showed a higher risk of stroke compared to controls, with hazard ratios ranging from 1.22 up to 4.08. Several cardiovascular risk factors are more frequently present in patients with iSSNHL than in the general population. The degree of white matter hyperintensities does not appear to be increased in patients with iSSNHL, while the risk of stroke following ISSNHL is increased. Prospective studies with larger study populations are needed to confirm the associations between generalized cardiovascular disease and iSSNHL and to assess whether these patients benefit from cardiovascular risk management to prevent future cardiovascular and cerebrovascular disease.

Screening and clinical characteristics analysis of familial hypercholesterolemia in a tertiary public hospital

Background and aims

Familial hypercholesterolemia (FH) is becoming a global burden. However, it remains underdiagnosed and undertreated worldwide. This study aimed to observe the screening rate of FH patients and department distribution among hospitalized patients using different diagnostic criteria.

Methods

A total of 45,410 inpatients with LDL-C ≥3.5 mmol/L between 2008 and 2019 were included from The Second Affiliated Hospital of Nanchang University. Inpatients are diagnosed and divided into groups by Dutch Lipid Clinic Network (DLCN) criteria, Chinese-modified DLCN criteria and Chinese expert consensus (CEC) criteria.

Results

There were 172, 1,076 and 115 inpatients included in the DLCN group, Chinese-modified DLCN group and CEC group, respectively (screening rates: 0.38%, 2.37% and 0.25%). These FH patients had a very high risk of atherosclerotic cardiovascular disease (ASCVD) (55.7%-74.4%), especially in the DLCN group and CEC group (70.4%-74.4%). More than half of the patients were in the Department of Cardiology, and other high-risk departments included Neurology, Nephrology, Vascular Surgery, Otolaryngology & Head Neck Surgery and Traditional Chinese Medicine (24.35%-31.51%). Overall, hypertension, coronary heart disease, carotid arteriosclerosis, hepatic cyst, arrhythmia, and nonalcoholic fatty liver disease were common accompanying diseases with FH.

Conclusions

It is necessary to establish appropriate diagnostic criteria and more positive treatment strategies for the FH inpatient population. In addition, promoting awareness of FH among doctors from other departments is also necessary. Therefore, developing a comprehensive management strategy for FH disease is very important.

Cardiovascular Risk and Sudden Sensorineural Hearing Loss: A Systematic Review and Meta-Analysis

OBJECTIVES/HYPOTHESIS

It was previously suggested that patients with idiopathic sudden sensorineural hearing loss (ISSNHL) have a higher risk of cardiovascular disease. The aim of this study is to determine if ISSNHL patients have an increased cardiovascular risk by means of a systematic review and meta-analysis.

METHODS

A systematic literature review was performed using PubMed, Embase, Cochrane Libraries and Web of Science. Studies with a clear definition of ISSNHL, investigating an association between traditional vascular risk factors and ISSNHL were included. Adhering to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, two reviewers extracted the data, assessed the risk of bias and performed the analysis of the collected evidence.

RESULTS

Nineteen case-control studies and two cohort studies were included (102,292 patients). Individual studies argued for higher prevalence of hypercholesterolemia, diabetes mellitus (DM) and higher blood pressure (HBP) in ISSNHL patients with a range of odds ratios (ORs) from 1.03 to 19. Pooled analysis of adjusted ORs revealed a significantly increased risk of ISSNHL for patients with hypertriglyceridemia (OR 1.54; 95% confidence interval [CI] 1.18-2.02) and high levels of total cholesterol (TC) (OR 2.09; 95% CI 1.52-2.87 after sensitivity analysis), but not for HBP, DM, or high levels of low- and high-density lipoproteins.

CONCLUSION

An association between higher vascular risk profile and ISSNHL seems apparent in high levels of triglycerides (TG) and TC, but more studies are needed to confirm this hypothesis due to the high levels of data heterogeneity in the literature.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:15-24, 2023.

Role of Blood Investigations in Idiopathic Unilateral Sensorineural Hearing Loss

Majority of unilateral sensorineural hearing loss are idiopathic. Hence, outcome depends on factors which are associated with nature of disease and its treatment. These can be sudden or progressive. Various studies are done to evaluate the association in sudden variety, however causality still lacks evidence. There are limited studies regarding progressive variety and its outcome. A prospective study of 40 patients with idiopathic unilateral SNHL was carried out which attempts at identifying factors associated with either disease severity or its prognosis. A significant association was seen between distribution of random blood sugar and post treatment improvement in patients with sudden USNHL (p = 0.045). No significant association was seen with other blood parameters to treatment outcome in sudden SNHL, and severity of progressive SNHL to any blood parameters. Elevated blood sugar may affect a negative effect on treatment outcome in unilateral ISSNHL. There is scarcity of evidence in scientific literature related to "Unilateral Idiopathic Progressive Sensorineural Hearing Loss" for any association/correlation with nature of disease.

Identification of dyslipidemia as a risk factor for sudden sensorineural hearing loss: A multicenter case-control study

Background

Recently, several studies have reported an association between lipid profiles and sudden sensorineural hearing loss (SSNHL), yet there is considerable variability between the individual studies in defining the precise association between serum lipids levels and SSNHL. This study sought to identify a possible relationship between dyslipidemia and the prevalence and prognosis of SSNHL.

Methods

A case‐control study was carried out at two independent medical centers, including 2,288 SSNHL patients and 2,288 healthy controls. Clinical characteristics and serum lipid parameters were assessed, including total cholesterol (CHOL), high‐density lipoprotein (HDL), low‐density lipoprotein (LDL), triglycerides (Trig), apolipoprotein AI (ApoAI), apolipoprotein B (ApoB), and lipoprotein a (Lpa). Multivariate logistic regression analysis was performed to assess the relationship between lipid profiles and SSNHL in the 4,576 subjects.

Results

Significant differences were identified in several conventional serum lipid markers including CHOL, Trig, HDL, LDL, ApoAI, ApoB, and Lpa, between SSNHL patients and healthy controls. Serum ApoAI levels were significantly lower in patients with bilateral SSNHL compared to unilateral SSNHL. Binary logistic regression analysis revealed that higher levels of ApoB, LDL, Trig, and lower levels of ApoAI and HDL were all associated with an increased risk of SSNHL. After clinical characterization, multivariate analysis showed that only low levels of ApoB predicted likelihood of a recovery of more than 30 dB among patients with SSNHL.

Conclusions

Serum lipids are associated with the incidence and prognosis of SSNHL. Identification of dyslipidemia may improve early evaluation and management of SSNHL risks.

Sudden Sensorineural Hearing Loss and Metabolic Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis is to examine the association between sudden sensorineural hearing loss (SSNHL) and risk of metabolic syndrome (MetS), and the association between MetS and prognosis of SSNHL.

DATABASES REVIEWED

We systematically searched MEDLINE, Embase, and Cochrane Central Register electronic databases from their dates of conception to February 4, 2020.

METHODS

We included observational studies analyzing 1) the prevalence of MetS among SSNHL patients, or 2) the prognosis of SSNHL patients in MetS patients. A standardized form was completed in duplicate extracting data on study characteristics, participant demographics, and SSNHL outcome or recovery measures. Random-effects meta-analyses were performed pooling odds ratios using the generic inverse method. Risk of bias was assessed using the Newcastle Ottawa Scale.

RESULTS

Three studies examining the prevalence of MetS among patients with SSNHL (11,890 total participants; 3,034 SSNHL participants) yielded a significantly increased risk of MetS among SSNHL, with a pooled odds ratio of 1.88 (95% CI, 1.01-3.50). Three studies examining the association of SSNHL prognosis in patients with MetS (608 SSNHL participants, 234 concomitant SSNHL, and MetS participants) demonstrated that SSNHL patients with MetS were significantly more likely to have poorer recovery compared to SSNHL patients without MetS (pooled odds ratio 2.77; 95% CI, 2.33-3.28).

CONCLUSION

Our findings suggest an association between prevalence of MetS and SSNHL, as well as poorer prognosis of SSNHL in patients with concomitant MetS.

Association of the prognosis and severity of idiopathic sudden sensorineural hearing loss with cervical ultrasonographic findings

OBJECTIVE

The aim of this study was to investigate the association of the prognosis and severity of idiopathic sudden sensorineural hearing loss (ISSNHL) with cervical ultrasonographic findings suggestive of cardiovascular risk.

METHODS

Seventy-four inpatients with ISSNHL were included in our study. Cervical ultrasonography was performed to evaluate the common carotid artery (CCA), internal carotid artery (ICA), and vertebral artery (VA). The peak systolic velocity, end diastolic velocity, intima-media thickness, pulsatility index (PI), and resistance index (RI) were evaluated. We investigated the relationship of these variables with the severity and prognosis of ISSNHL.

RESULTS

ICA-PI, ICA-RI, and CCA-RI were significantly higher in patients with poor hearing prognosis than in those with good prognosis. The variables of VA were not related to the prognosis of ISSNHL. There were no statistically significant differences between ISSNHL severity and cervical ultrasonographic findings.

CONCLUSIONS

We found that PI and RI might be prognostic factors for ISSNHL.

Biomarkers Suggesting Favorable Prognostic Outcomes in Sudden Sensorineural Hearing Loss

Sudden sensorineural hearing loss (SSNHL) is a medical emergency, making detailed examination to determine possible causes and early treatment important. However, etiological examinations in SSNHL do not always reveal a cause, and several factors have been found to affect treatment outcomes. Various studies are being performed to determine the prognosis and effects of treatment in patients who experience sudden hearing loss, and to identify biomarkers associated with this condition. Embase, PubMed, and the Cochrane database were searched using the key words SSNHL, prognostic, and biomarker. This search identified 4 articles in Embase, 28 articles in PubMed, and 36 in the Cochrane database. Of these 68 articles, 3 were duplicates and 37 were unrelated to the research topic. After excluding these articles, the remaining 28 articles were reviewed. Factors associated with SSNHL were divided into six categories: metabolic, hemostatic, inflammatory, immunologic, oxidative, and other factors. The associations between these factors with the occurrence of SSNHL and with patient prognosis were analyzed. Low monocyte counts, low neutrophil/lymphocyte ratio (NLR) and monocyte/high-density lipoproteins (HDL) cholesterol ratio (MHR), and low concentrations of fibrinogen, platelet glycoprotein (GP) IIIa, and TNF-α were found to be associated with good prognosis. However, these factors alone could not completely determine the onset of and recovery from SSNHL, suggesting the need for future basic and clinical studies.

Metabolic syndrome and idiopathic sudden sensori-neural hearing loss

The purpose of this study was to evaluate the association between the presence of Metabolic Syndrome (MetS) and idiopathic sudden sensorineural hearing loss (ISSHL) and the impact of MetS on recovery of patients with ISSHL. 39 Patients with ISSHL and 44 controls were enrolled in this study. Demographic, clinical characteristics and hearing recovery were evaluated. MetS was defined according to the diagnostic criteria of International Diabetes Federation (IDF) consensus definition. Patients affected by ISSHL presented a body mass index (BMI), waist circumference, waist hip ratio (WHR), fasting glucose and blood pressure significantly higher compared to controls. Considering patients with central obesity, 5 controls and 15 ISSHL patients met the criteria of MetS. According to Siegel criteria, a complete or partial recovery was observed in 60% of patients with MetS and in 91,66% of patients without MetS. MetS was associated with ISSHL and this association negatively influenced the hearing recovery of these patients.

Metabolic syndrome components and sudden sensorineural hearing loss: a case-control study

PURPOSE

Cardiovascular risk factors, including metabolic syndrome (MetS) components, were reported as possible risk factors of sudden sensorineural hearing loss (SSNHL). The objective of this study was to evaluate the relationship between MetS (and its components) and SSNHL.

METHODS

Eighty-one SSNHL patients and 243 sex-, aged-matched controls participated from January 2018 to July 2019. The participants included 176 (54.3%) men and 148 (45.7%) women. The correlation between Mets components, total cholesterol, low-density lipoprotein-cholesterol, and the onset of SSNHL was analyzed using used multivariate conditional logistic regression analysis.

RESULTS

A total 12 patients (14.8%) with SSNHL and 27 subjects (11.1%) in control group had MetS (p > 0.05). The rate of low levels of high-density lipoprotein-cholesterol (HDL-C), hypertriglyceridemia, and hypertension was significantly higher in the SSNHL group than those in the control group (p < 0.05). A trend of odds SSNHL was observed with increasing the number of MetS components (p < 0.001). The multivariable analysis revealed that the rate of hypertriglyceridemia and low HDL-C concentration was significantly higher in the SSNHL groups compared to the controls.

CONCLUSIONS

Hypertriglyceridemia and low levels of HDL-C may be important factors in the pathogenesis of SSNHL, and should be assessed during the investigation of patients with this condition.