Retrospective Analysis of Atypical Chest Pain Presentations in Older Adults and Their Association With Missed Acute Coronary Syndrome Diagnosis in the Emergency Department: National Hospital Ambulatory Medical Care Survey (NHAMCS)-Based Study.

Background Atypical symptom presentations of Acute Coronary Syndrome (ACS) are common in older adults and may contribute to diagnostic delays or missed recognition in emergency departments (EDs). National-level data examining this relationship remains limited. Objective To evaluate whether atypical chest pain presentations are associated with reduced likelihood of ACS diagnosis among U.S. adults aged 65 years and older during ED visits. Methods We conducted a retrospective cross-sectional study using data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2014 to 2020. ED visits by adults aged ≥65 years were analyzed. Atypical presentations were defined using Reason for Visit (RFV) codes for symptoms such as weakness, dyspnea, dizziness, nausea, syncope, and abdominal pain. The primary outcome was an ED diagnosis of ACS based on ICD-9-CM codes. Multivariable logistic regression was used to assess associations. Results Among 2,470 eligible ED visits, only 15 (0.6%) were diagnosed with ACS. Of those, 7 (46.7%) presented with atypical symptoms. Atypical presentation was not significantly associated with ACS diagnosis (OR: 0.90; 95% CI: 0.32-2.49; p = 0.83). No significant associations were found with age, sex, race/ethnicity, or ED disposition. The variable "admitted to hospital from ED" was excluded due to collinearity. Conclusion Nearly half of older adults diagnosed with ACS presented atypically, yet atypical presentation was not significantly associated with missed ACS diagnosis in the ED. Given the limitations of administrative data and low ACS event rates, future research using richer clinical datasets and follow-up outcomes is needed to better understand diagnostic gaps in this high-risk population.