Respiratory Illness Emergency Department Visits in the National Hospital Care Survey and the National Hospital Ambulatory Medical Care Survey.

Purpose-This report compares emergency department (ED) visits for respiratory illness between the 2014 National Hospital Care Survey (NHCS) and the 2014 National Hospital Ambulatory Medical Care Survey (NHAMCS) to determine the potential of researching respiratory illness in EDs with non-nationally representative NHCS data. The 2014 NHCS data linked to records in the 2014-2015 National Death Index (NDI) are also described to provide results on mortality after ED visits for respiratory illness. Methods-For both surveys, encounters with respiratory illness were identified using diagnosis codes from the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Weighted NHAMCS percentage estimates and their 95% confidence intervals (CIs) are shown for all demographic characteristics. Unweighted NHCS percentages are presented for all demographic and health care characteristics and are compared with weighted NHAMCS percentage estimates and used to report NHCS-only results. Standard errors and CIs are also presented for the NHCS unweighted percentages as a measure of variability. Results-The percentage of NHCS ED visits for respiratory illness fell within NHAMCS measures of statistical variation for overall and specific respiratory illnesses. Additionally, respiratory illness by sex, older age groups, older men, and female patients of all ages fell within these measures. Compared with NHAMCS, NHCS had a higher percentage of ED visits for respiratory illness for both infants (under 1 year) and children (1-17 years) but a lower percentage for adults aged 18-44. NHCS data show that 15.2% of patients with ED visits for respiratory illness were hospitalized and of those hospitalized, 6.6% died within 90 days post-discharge. However, 11.1% of patients admitted to the intensive care unit died within 90 days. Conclusion-Although the 2014 NHCS data are not nationally representative, the data may be used for exploratory analyses and have analytical capabilities that are not available in other hospital surveys.