Hearing Impairment Disproportionately Affects Patients With SCD, Further Studies Required

Patients with sickle cell disease (SCD) and sickle cell traits (SCTs) have higher rates of hearing loss compared with patients with the hemoglobin A (HbA) genotype. This discrepancy could be influenced by higher frequencies of blood transfusions, drug interventions, and hospitalizations this patient population experiences, according to a recent study published in Nigerian Journal of Clinical Practice.

Woman Experiencing Hearing Issues Model | image credit: Rene La/peopleimages.com - stock.adobe.com

SCD and SCTs affect Black individuals at increased rates. Nigeria in particular endures a high 3% and 39% incidence rate for SCD and SCTs, respectively. For comparison, the estimated prevalence rates of SCD in Africa, throughout Europe, and globally are 1.12%, 0.04%, and 0.11%, according to a 2018 meta-analysis.

Those impacted by SCD carry heightened risks of infection, chronic hemolytic anemia, end-organ damage, and more when not managed properly. One of the organs at risk in these patients is the cochlea, which can be affected by vaso-occlusive occurrences that stunt its arterial supply—resulting in a myriad of possible hearing impairments that include hearing loss.

Despite the increased prevalence in African populations and the associated risks, the authors of the present study mention that detailed research on SCD-related hearing loss in this population is lacking. Furthermore, existing studies have not paid adequate attention to the characteristics of hearing impairment in younger children. To address these gaps in knowledge and advocate for regular auditory and hearing assessments in patients with SCD and SCTs, researchers conducted a comparative cross-sectional study analyzing the relationship between SCD, SCTs, and hearing loss in affected adults and children.

A total of 212 patients participated in this study; 106 patients with confirmed SCD (HbSS genotype) or SCTs (HbAS genotype) were age- and sex-matched with 106 healthy controls (HBA genotype). All patients had assessments done on their ears and hearing. Participants over 5 years of age underwent otoscopy, speech audiometry, tympanometry, and pure-tone audiometry (PTA). Participants under 5 years of age had otoscopy, tympanometry, and auditory brainstem response (ABR) or otoacoustic emissions (OAEs).

There were 124 children (aged 6 months-17 years) and 88 adults included in the analysis. The HbSS and HbAS groups consisted of 80 and 26 patients, respectively. Among HbSS individuals, 30.8% of this group had hearing impairments compared with 18.8% of controls (P < .035). Impairment severity was mild to moderate across every group; asymmetrical hearing loss or impairment was more frequently seen in the right ear.

In adults, hearing loss occurred in both ears at rates of 36.1% (P < .002) among those with HbAS and 30% (P < .01) among those with HbSS compared with 11% in controls. Compared with children, adults in the cohort groups exhibited a higher proportion of auditory impairment.

Once the analysis adjusted for certain risk factors such as blood transfusion, drug interventions, hospitalization frequency, and more, the data revealed that individuals in the HbAS group had more than triple the risk of developing a hearing impairment—notably, in the left ear (OR, 3.33; 95% CI, 1.07-9.81; P = .0309). Compared with the control group, those in the HbSS cohort were observably twice as likely to have a hearing impairment (OR, 2.14; 95% CI, 1.0-4.46; P = .0445). While there was a significant difference seen between patients with SCD or SCT and controls, the authors noted that there were no significant differences between adults and children in the SCD or SCT groups. Furthermore, they also mentioned that adults more commonly had impairments in the right ear whereas children experienced impairments in the left.

These results demonstrated the clear heightened prevalence of hearing impairments in children and adults with SCD and SCTs. As the researchers conclude, they think ahead to future studies and suggest they consider more thoroughly the characteristics and determinants of hearing loss to develop a more comprehensive understanding of the risk factors in play for this population.

Reference

Ibekwe TS, Rogers C, Ramma L. Comparing hearing loss in children with adults living with sickle cell disease and sickle cell traits. Niger J Clin Pract. 2024;27(1):74-81. doi:10.4103/njcp.njcp_763_23