Hearing Loss at Primary Health Care Clinics in South Africa : Novel Screening Approaches and Prevalence

Abstract

Hearing loss is a serious disability that not only affects the individual and the family but also places a heavy burden on resources of communities and countries. Access to hearing care is unfortunately limited and services are often reserved for tertiary and secondary hospitals, universities and practices in the private sector. This project aimed to determine approaches that could be used to detect hearing loss accurately and affordably in primary health care clinics. More specifically, the project evaluated the performance of low-cost, smartphone-based hearing screening at primary health care clinics. The project also investigated the performance of hearing screening using self-reported hearing loss and pure tone audiometry in primary health care clinics. Furthermore, the project aimed to determine the prevalence of hearing disorders in patients three years of age and older, as well as the nature and characteristics of hearing disorders found at primary health care clinics. The project aimed to provide research-based recommendations for clinical practice of hearing detection at primary health care clinics. Nonprobability purposive sampling was used at both primary health care clinics to evaluate the performance of low-cost, smartphone-based hearing screening. 1236 participants were included in the final analysis and participants were screened using the hearScreen™ application following a two-step screening protocol and diagnostic pure tone audiometry to confirm hearing status. Sensitivity and specificity for smartphone screening was 81.7% and 83.1% respectively. Gender [2(1, N=126)= .304, p>.05] and race [2(1, N=126) = .169, p>.05)] had no significant effect on screening outcome for children whilst for adults age (p<0.01; .04) and gender (p=0.02; -.53) had a significant effect on screening outcomes with males more likely to fail. Initial screening test times were less than a minute (48.8s ± 20.8 SD) for adults and slightly more than a minute for children (73.9s ± 44.5 SD). The hearScreen™ smartphone application provides time-efficient identification of hearing loss with adequate sensitivity and specificity for accurate testing at primary health care settings. To evaluate the performance of self-reported hearing loss in isolation, and a combination of self-reported hearing loss and pure tone audiometry screenings in primary health care clinics in South Africa, nonprobability purposive sampling was used at both primary health care clinics and 1084 participants were included. It was found that 40.2% self-reported a hearing loss with no significant association with gender or race. Self-reported hearing loss increased significantly with increasing age. A hundred and thirty six participants (12.5%) self-reported hearing loss and failed audiometry screening (35 dB HL at 1, 2 and 4 kHz). Combining self-report with a second stage audiometry screening revealed a high test accuracy (81.0%) for hearing loss, was the most accurate procedure (86.1%) for the identification of high frequency hearing loss. Whilst self-report of hearing loss is an easy and time-efficient screening method to use at primary health care clinics, its accuracy may be limited when used in isolation and it may not be sufficiently sensitive to detect hearing loss. Combining a simple audiometry screening as a second-stage screen can significantly improve overall performance and efficiency of the screening protocol. To determine the prevalence of hearing disorders, a cross-sectional design was used in patients three years of age and older attending two primary health care clinics. Nonprobability purposive sampling was used and 1236 participants were screened. It was found that the hearing loss prevalence was 17.5% across both clinics. Furthermore, most hearing losses were bilateral (70.0%) and were of a sensorineural nature (84.2%). Participants 40 years and older were at significantly higher risk for hearing loss. Decentralizing hearing services to primary health care clinics could alleviate negative effects and high expenses usually experienced due to hearing loss. Using selfreported hearing loss in combination with smartphone technology provides the possibility to expand and decentralize hearing care services to primary health care level. Furthermore, prevalence data suggests that 17.5% of people present with some form of hearing loss. These findings provide valuable baseline data to motivate for the inclusion of hearing care at primary health care clinics. Furthermore, these findings provide baseline data to plan and identify specific program goals and specification of care pathways to support implementation of sustainable hearing services across primary health care clinics in South Africa.