L’ischémie cochléaire : des données fondamentales aux espoirs cliniques

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.

Risk factors for idiopathic sudden sensorineural hearing loss and their association with clinical outcome

BACKGROUND

Sudden sensorineural hearing loss (ISSHL) is idiopathic in 85% of cases and cochlear micro-thrombosis has been hypothesized as pathogenic mechanism. The role of thrombophilia and cardiovascular risk factors in ISSHL is controversial and whether these risk factors influence the clinical outcome of ISSHL is unknown.

METHODS

and patients To investigate the role of thrombophilia and cardiovascular risk factors in ISSHL and to evaluate their influence on clinical outcome of the disease, 118 patients with a first episode of ISSHL and 415 healthy controls were investigated. Thrombophilia screening included measurements of antithrombin, protein C, protein S, factor V Leiden, prothrombin G20210A, antiphospholipid antibodies, fibrinogen, factor VIII and homocysteine.

RESULTS

Deficiencies of antithrombin, protein C or S taken together, high factor VIII and hyperhomocysteinemia were significantly associated with ISSHL (OR [95%CI]: 7.55 [1.05-54.47], 2.91 [1.31-6.44] and 2.69 [1.09-6.62], respectively), whereas no association was found with the remaining thrombophilia markers. A 2-fold increased risk of poor clinical outcome was observed for every 5 μmol/L increase of fasting homocysteine levels (adjusted OR [95%CI]) 2.13 [1.02-4.44]) until levels of approximately 15 μmol/L, then the risk increased slowly. Cardiovascular risk factors (arterial hypertension, hyperlipidemia, diabetes and smoking) were associated with an increased risk of ISSHL (OR [95%CI] 1.88 [1.17-3.03]) and with a poor clinical outcome (OR [95%CI] 2.22 [0.93-5.26]).

CONCLUSIONS

Hyperhomocysteinemia, high factor VIII and, with more uncertainty, deficiencies of antithrombin, protein C or S and cardiovascular risk factors increase the risk of ISSHL. Hyperhomocysteinemia and cardiovascular risk factors are associated with a poor clinical outcome of ISSHL.