Differential access to care: The role of age, insurance, and income on race/ethnicity-related disparities in adult perforated appendix admission rates

Background Differences in perforated appendix admission rates (PAAR) are an ambulatory-sensitive measure of access to care. While pediatric studies report disparities in PAAR, initial adult investigations suggest a lack of racial/ethnic inequity. The objectives of this study were to (1) assess for risk-adjusted, racial/ethnic differences in PAAR among adults on a national scale, (2) consider the extent to which variations (or lack thereof) are explained by age, insurance, and income, and (3) compare results within the United States population to a national segment of the population who are completely insured. Methods According to the Agency for Healthcare Research and Quality definition of PAAR, adults (aged 18-64 years) in the 2006–2010 Nationwide Inpatient Sample were queried for the occurrence and perforation of acute appendicitis. Risk-adjusted differences were compared by race/ethnicity over 5-year age increments using logistic regression with reweighted estimating equations. Noting disparate outcomes between younger (aged 18-34 years) versus older (aged 35-64 years) adults, age-stratified variations were further considered. Results were compared relative to differences among national military/civilian-dependent patients with universal insurance and were assessed for the extent to which disparities could be explained by variations in insurance and income. Results A total of 129,257 (weighted: 638,452) patients were included. Despite a lack of differences overall, significantly worse outcomes among younger (odds ratio point-estimates ranged from 1.11–1.32) and better outcomes among older (0.78–0.93) minority patients were found. This observation contrasted a lack of differences among completely insured military/civilian-dependent patients (n = 12,154). A total of 22.4% (non-Hispanic black versus non-Hispanic white) and 39.0% (Hispanic versus non-Hispanic white) of younger adult differences were explained by insurance—12.2% and 13.6% by income, 29.8% and 44.0% combined. Conclusion This national assessment of differences in access to care among adults with acute appendicitis demonstrated the existence of racial/ethnic disparities in PAAR that varied with age and were partially, although incompletely, explained by variations in insurance and income.