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Congenital microcephaly hospitalizations in California infants: 1999-2013
Maya R Krasnow1, Yvonne A Maldonado1,2, Despina G Contopoulos-Ioannidis2
1Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California.
Introduction:
Population-level changes in microcephaly incidence risk (IR) could signal circulation of neurotropic pathogens or potential emerging teratogen exposure.
Methods:
In this retrospective population cohort study, we estimated the IR of hospitalizations with a microcephaly ICD-9-CM discharge diagnosis code among infants ≤1 year over a 15-year period (1999-2013) using the Electronic Health Record (EHR) database from all hospital discharges in California from the Office of Statewide Hospital Planning and Development (OSHPD) database. We calculated the overall and yearly IRs per 10,000 live births (LBs) and per 10,000 hospitalizations in infants ≤1 year, and explored the impact in the IR estimates when children with microcephaly associated comorbidities were excluded or not.
Results:
Among 8,860,153 hospital discharges of infants ≤1 year in the OSHPD database over this 15 year period, we identified 6,004 hospitalizations with a microcephaly discharge diagnosis code; 3,526 of those were in neonates ≤30 days. The IR of microcephaly hospitalizations for infants ≤1 year was 7.70/10,000 LB (for neonates it was 4.52/10,000 LB) and 6.78 per 10,000 hospitalizations ≤1 year. There was large heterogeneity in the yearly microcephaly IRs (I2 = 66.6%).
Discussion:
EHR collected data could be used as a complementary approach to track epidemiologic changes in microcephaly IRs. However, standardization in the use of microcephaly discharge diagnosis code and harmonization in the types of additional comorbidities to be excluded across analyses is mandatory to allow for prompt identification of true changes in microcephaly rates over time.
Insights
Population-level microcephaly incidence risk (IR) was tracked using California hospital data from 1999-2013. Electronic Health Records can monitor microcephaly rates, but require standardized coding for accuracy.
Area of Science:
- Epidemiology
- Public Health Surveillance
Background:
- Population-level microcephaly incidence risk (IR) changes can indicate neurotropic pathogen circulation or teratogen exposure.
- Electronic Health Records (EHR) offer a potential tool for monitoring these critical public health indicators.
Purpose of the Study:
- To estimate the incidence risk (IR) of hospitalizations with microcephaly diagnoses in infants up to one year old.
- To analyze trends in microcephaly IR over a 15-year period (1999-2013) using a large healthcare database.
Main Methods:
- Retrospective population cohort study utilizing the California Office of Statewide Hospital Planning and Development (OSHPD) database.
- Analysis of hospital discharge data for infants ≤1 year, identifying microcephaly codes (ICD-9-CM).
- Calculation of IR per 10,000 live births and per 10,000 infant hospitalizations, with exploration of comorbidity exclusion impacts.
Main Results:
- Over 8.8 million infant hospital discharges were analyzed, identifying 6,004 microcephaly cases.
- The overall IR of microcephaly hospitalizations was 7.70 per 10,000 live births for infants ≤1 year.
- Significant yearly heterogeneity in microcephaly IR was observed (I² = 66.6%).
Conclusions:
- EHR data can complement traditional methods for tracking microcephaly IR.
- Standardization of microcephaly diagnosis coding and comorbidity exclusion criteria is crucial for accurate temporal analysis.
- Improved data harmonization is necessary for the prompt identification of true changes in microcephaly rates.
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