Primary care availability and emergency department use by older adults: a population-based analysis.

OBJECTIVES: To assess the relationship between the number of primary care providers (PCPs) in an area and emergency department (ED) visits by older adults.
DESIGN: Population-based cross-sectional observational study.
SETTING: Nonfederal EDs in North Carolina in 2010. PARTICIPANTS: All older adults (n = 640,086) presenting to a nonfederal ED in North Carolina in 2010. MEASUREMENTS: The primary outcome was the number of ED visits by older adults in each ZIP code per 100 adults aged 65 and older living in that ZIP code. A secondary outcome was the number of ED visits not resulting in hospital admission per 100 older adults. The primary predictor variable was the number of PCPs per 100 older residents for each ZIP code. Covariates included those representing healthcare need (Medicare hospitalizations, nursing home beds), predisposing factors for healthcare use (race, education, population density of older adults), and enabling factors (distance to the nearest ED).
RESULTS: In a multivariable regression model corrected for spatial clustering, ZIP code characteristics associated with ED visits included more hospitalizations by Medicare beneficiaries, more nursing home beds, and closer proximity to an ED. Number of PCPs per 100 older adult residents in each ZIP code was not associated with ED use, and the 95% confidence limit indicates at most a small effect of PCP availability on ED use.
CONCLUSION: These findings suggest that primary care availability has at most a limited effect on ED use by older adults in North Carolina.