Measuring Meconium Aspiration Syndrome With Discharge Data [31N

Abstract

INTRODUCTION: Discharge data (International Classification of Diseases ICD codes) have not been used to estimate population level incidence of meconium aspiration syndrome (MAS) in the U.S. Existing population estimates are at least 15 years old and based on vital statistics data which are no longer collected. Estimates from other nations have used combined and disparate ICD codes (“with” and “without” respiratory symptoms). METHODS: We compared MAS diagnoses “with” and “without” respiratory symptoms using nationally representative newborn hospital discharges 2010-2012 (Nationwide Inpatient Sample-KIDS data). We compared incidence and outcomes of each MAS diagnosis controlling for demographic and hospital characteristics. RESULTS: Incidence of MAS with symptoms was 2.49/1000; 1.15/1000 without symptoms. Almost 1/3 (32%) of MAS cases identified by ICD codes were “without respiratory symptoms.” Odds ratio of MAS with symptoms was 1.54 (95% C-I 1.39-1.73) for African American newborns compared to whites. Length of stay was nearly twice as long (6.68 versus 3.65 days) and total charges were nearly 3 times higher ($44,000 versus $15,461) for newborns with symptoms than those without. Crude and adjusted OR's for hypoxic ischemic encephalopathy, pulmonary hypertension of the newborn, facility transfers and mortality are attenuated when disparate ICD codes are combined compared to cases “with symptoms” alone. CONCLUSION: ICD codes for MAS represent very different diseases or disease severity. Discharge data is useful in providing population estimates of MAS incidence, but diagnosis severity should be clearly distinguished by researchers. Combining disparate MAS diagnoses misrepresents incidence and disease severity, complicating population level comparisons and prevention strategies.