Risk indicators for hearing loss in infants treated in different neonatal intensive care units

To assess which infants' characteristics and specialized procedures are risk indicators for unilateral or bilateral hearing loss (HL) and to evaluate whether these risk indicators are associated with variation in prevalence of HL between Neonatal Intensive Care Units (NICUs).

For 2002-2005, data from the NICU hearing screening database in the Netherlands were matched with the national neonatology database in which all NICU infants with their patient characteristics and specialized procedures are registered. Multivariate logistic regression analyses were performed to assess risk indicators for HL and to explain differences in prevalence rates between NICUs.

A total of 10 830 infants were available for analyses. The prevalence of HL was 1.8% and ranged from 0.7 to 3.7% between NICUs. Infants' characteristics that significantly increased the risk of HL were the presence of craniofacial anomalies, chomosomal/syndromal anomalies, central nervous system conditions, circulatory system conditions and intra-uterine infections. The specialized procedures involving > or =12 days of intensive care and high frequency oxygenation ventilation were independent risk indicators for HL. Approximately 20% of the variance can be explained by the studied risk indicators. Differences in prevalence rates between NICUs were slightly reduced after adjustment for these risk indicators. NICUs with the highest prevalence rates of HL were situated in the largest cities in the Netherlands with a mixed population because of immigration. Therefore, ethnicity may be a risk indicator.

Several independent risk indicators for HL were found, but they could not explain all differences in prevalence rates of HL between NICUs.