Permanent childhood hearing impairment in infants admitted to the neonatal intensive care unit: nested case-control study.

The prevalence of permanent childhood hearing impairment (PCHI) in infants admitted to a neonatal intensive care unit (NICU) is higher than that in the general population. Our study objective was to identify risk factors associated with PCHI in infants who required admission to the NICU for more than 48 h. We performed a case-control study, including infants of all gestational ages who were admitted to NICU for more than 48 h and who underwent newborn hearing screening between 2005 and 2019. Infants admitted to NICU and diagnosed with PCHI by formal audiology were classified as "cases". The "controls" were infants who were admitted to NICU and did not have PCHI. Cases and controls (1:4) were matched based on their birth gestation, birthing place, and treating NICU. The prevalence of PCHI in infants admitted to NICU was 6.3% as compared with our general population prevalence of 0.25%. There were 77 cases and 269 controls during the study period. The median age at diagnosis of PCHI in these infants was 132 days (interquartile range 75.5-518.5). Using regression analysis, "any ventilation episodes", presence of seizures, and major congenital anomalies were significantly associated with PCHI in infants of all gestational ages. There were higher prevalence of PCHI in preterms (<32 weeks) who received furosemide and lower prevalence with antenatal use of magnesium sulphate.Conclusions: In our study, the prevalence of hearing loss was high in infants admitted to NICU. Gestation-specific risk factors identified in this case-control study would help in counselling of parents. What is Known: • In the UK, 1-2/1000 infants are born with hearing loss and infants admitted to the neonatal unit for 48 h or more have increased prevalence of hearing loss (1 in 100 live births). • Identification of risk factors in infants admitted to neonatal unit would help with risk stratification and further management. What is New: • In our study, infants admitted to the neonatal unit had higher prevalence of hearing loss (6.3 in 100 live births). • In infants across all gestational age "any ventilation episodes", presence of seizures, and severe congenital anomalies were associated with a statistically significant increase in prevalence of hearing loss. Higher prevalence of hearing loss was noted in preterm infants (<32 weeks) who received furosemide treatment and lower prevalence was noted with antenatal use of magnesium sulphate.