Delayed thrombolytic treatment of older patients with acute myocardial infarction

OBJECTIVE: To determine demographic and clinical factors associated with de layed thrombolysis in patients with acute myocardial infarction. DESIGN: A retrospective cohort. SETTING: 37 Minnesota hospitals during the time periods October 1992-July 1 993 and July 1995-April 1996. PATIENTS: We reviewed the medical records of 776 older patients aged 65 or older hospitalized with an admission diagnosis of acute myocardial infarcti on, suspected acute myocardial infarction, or rule-out acute myocardial inf arction, who were treated with a thrombolytic agent. MEASUREMENT: We used multivariate logistic regression models to examine the association between selected study characteristics and time between hospit al presentation and administration of thrombolytic treatment. Early thrombo lysis was defined as less than 60 minutes after hospital presentation and l ate thrombolysis as 60+ minutes. RESULTS: Of 776 study patients, 57.5% (n = 446) received early thrombolysis . Of the remaining 330 patients receiving late treatment, 12.1% (n = 94) we re thrombolyzed more than 2 hours after hospital presentation. After contro lling for other factors, the odds of delayed thrombolysis among patients ag ed 75 or older were 1.48 compared with younger individuals (95% CI, 1.17-1. 88). The odds of delayed thrombolysis among patients with severe comorbidit y were 1.46 (95% CI, 1.10-1.94) compared with individuals without severe co morbidity. Predictors of early thrombolytic treatment included hospital arr ival via emergency transport (ORdelay = 0.46; 95% CI, 0.34-0.63) and chest discomfort at admission (ORdelay = 0.40; 95% Cl, 0.18-0.86). CONCLUSIONS: The present study indicates that patients of advanced age and with severe comorbidity are more likely to experience delayed thrombolytic treatment after hospital presentation. These are the patients who suffer th e highest morbidity from acute myocardial infarction and for whom expeditio us treatment may enhance therapeutic benefit.