Comparison of newborn hearing screening results between well babies and neonates admitted to the neonatal intensive care unit for more than 5 days: Analysis based on the national database in Korea for 9 years

OBJECTIVE: The purpose of this cohort study is to compare newborn hearing screening (NHS) results between healthy newborns and neonates who were admitted to the neonate intensive care unit (NICU) for more than 5 days based on the national database for 9 years. Ultimately, we’ve tried to analyze the associated factors necessary to manage the national NHS program according to the group, which would help to establish policy to effectively detect and support hearing impaired children and which would help to control qualities. METHODS: The Ministry of Health and Welfare (MHW) introduced a nationwide coupon-mediated program for the low-income class since 2009. The coupon consisted of two parts, the screening part and the confirming parts with the same unique number, and the MHW supported the cost of one screening test and one diagnostic auditory brainstem response (ABR) test for infants who did not pass from the screening test. We have analyzed the screening test performing rate, the referral rate according to the screening methods or institutions, the prevalence of hearing loss, and the average age of hearing loss diagnosis. Hearing loss was defined as any hearing impairment either unilateral or bilateral with the hearing threshold ≥ 40 dB nHL on the diagnostic ABR test, irrespective of its etiology. RESULTS: A total of 524,371 newborns were enrolled in the study, and 506,634 (96.6%) neonates were in the “well-baby group (WBG)”, while 17,737 (3.4%) were in the “high-risk group (HRG)”. The referral rate of the screening test was 1.5% in average, 1.3% in the WBG, and 7.5% in the HRG. The referral rates varied according to the screening methods and screening institutions. The adjusted prevalence of HL was 5.6/1,000 in average, 4.6/1,000 in the WBC, and 28.8/1,000 in the HRG. The screening tests were performed 4.3 ± 6.7 days after birth and the diagnostic tests were done 62.7 ± 37.5 days after birth in WBG. In HRG, dates were 17.7 ± 19.3 days and 97.6 ± 51.4 days, respectively. CONCLUSIONS: The prevalence of hearing loss in infants who were hospitalized in NICU for more than 5 days was about seven times higher than that in healthy newborns. However, different referral rates were noted depending on both institutions and the screening methods. These differences need to be addressed in order to improve our program and ensure that all neonates with hearing loss, especially neonates with high risk factor, are detected and appropriately referred for the treatment.