Abstract 107: Decade Long Trends (1999 - 2009) in Pre-hospital Delay and Short-term Mortality in Patients Hospitalized for Acute Myocardial Infarction - The Worcester Heart Attack Study

Abstract

Objective: Patients experiencing signs and symptoms of an acute myocardial infarction (AMI) require prompt evaluation and treatment. There are little contemporary data, however, available on how the extent of delay between the onset of acute coronary symptoms and hospital presentation may impact short-term mortality. The purpose of this population-based study was to examine the relationship between extent of pre-hospital delay with hospital case-fatality rates (HCFRs) and 30-day post-admission mortality rates (PAMRs) among patients hospitalized with validated AMI in all central Massachusetts medical centers, and trends over time therein. Methods: We examined the medical records of residents of the Worcester, MA, metropolitan area hospitalized with a confirmed AMI at all 11 central MA medical centers on a biennial basis between 1999 and 2009 (n = 6,017). Information on patient’s demographic, medical history, clinical characteristics, and time of acute symptom onset and hospital arrival was abstracted. Results: Hospital medical record data on pre-hospital delay were available for 2,913 (48%) subjects of whom their mean age was 68 years, 38% were female, and 90% were Caucasian. The mean and median pre-hospital delay times were 4.0 hours and 2.0 hours, respectively, with little change noted in these times between 1999 and 2009. Patients who reported pre-hospital delay times greater than two hours were more likely to be older, female, and have a history of heart failure or diabetes mellitus as compared with patients who delayed seeking medical care by less than 2 hours. The overall HCFR was 6.6% and 30-day PAMR was 9.4%. The average HCFRs and 30-day PAMRs varied slightly between those with delay times of less than 2 hours (6.5%, 9.2%), 2 to 4 hours (6.3%, 8.6%), and greater than 4 hours (7.0%, 10.6%). No statistically significant changes in HCFRs and 30-day PAMRs were observed as pre-hospital delay times increased. Analyses of our principal study outcomes according to type of AMI (e.g., STEMI and NSTEMI) are ongoing and will be presented subsequently. Conclusions: This population-based study of residents of central MA hospitalized with AMI in all metropolitan Worcester medical centers showed little change in average and median pre-hospital delays between 1999 and 2009. Both the HCFRs and 30-day PAMRs were not significantly increased with greater durations of pre-hospital delay possibly due to potential confounders such as symptom severity. Our preliminary results suggest the need to further investigate trends in pre-hospital delay and short-term mortality, including patients who die in the community before receiving acute medical care.