False-Positive Newborn Screening Result and Future Health Care Use in a State Medicaid Cohort

OBJECTIVE: To compare health care visit rates between infants with false-positive and those with normal newborn screening (NBS) results. PATIENTS AND METHODS: We analyzed administrative claims of Medicaid-enrolled infants born in Michigan in 2006 and calculated the average number of outpatient, emergency department, and hospital visits for infants aged 3 to 12 months according to NBS results. We calculated an adjusted incidence rate ratio for each visit category, adjusting for covariates and accounting for interaction effects. RESULTS: Of the 49 959 infants in the analysis, 818 had a false-positive NBS result. We noted a significant interaction between gestational age and NBS results. We found that preterm, but not term, infants with false-positive results had more acute outpatient visits than their counterparts with normal NBS results. We found no difference in adjusted rates of other visit types (emergency department, inpatient, outpatient well) between infants with false-positive and normal NBS results, regardless of gestational age. CONCLUSIONS: Increased rates of acute outpatient visits among preterm infants with false-positive NBS screening results may be attributable to underlying chronic illness or parental anxiety. The absence of increased health care utilization among term infants may be unique to this Medicaid population or a subgroup phenomenon that was not detectable in this analysis. Pediatrics 2011;128:715-722