RECENT AGE-RELATED TRENDS IN THE USE OF THROMBOLYTIC THERAPY IN PATIENTS WHO HAVE HAD ACUTE MYOCARDIAL-INFARCTION

Objective: To examine recent trends in the use of thrombolytic therapy in elderly patients who have had acute myocardial infarction and to d etermine whether failure to meet time-to-hospital presentation and ele ctrocardiographic criteria might explain age-related differences in th e use of thrombolytic therapy. Design: A national registry of patients who have had acute myocardial infarction. Setting: 1249 U.S. hospital s. Patients: 350 755 patients who had an acute myocardial infarction f rom 1 July 1990 to 30 September 1994. Measurements: Trends in the prop ortions of patients who received thrombolytic therapy were examined ac cording to age and sex. The association between age and treatment with a thrombolytic agent was determined by crude and multivariable-adjust ed analyses. Results: Use of a thrombolytic agent was inversely relate d to patient age: Almost 51% of patients younger than age 55 years rec eived a thrombolytic agent during hospitalization for acute myocardial infarction; this proportion decreased to 43.6% for patients aged 55 t o 64 years, 33.0% for those aged 65 to 74 years, 19.0% for those aged 75 to 84 years, and 7.4% for those aged 85 years or older. However, re lative increases in the use of thrombolytic therapy over time were gre atest for patients in the oldest age groups. Between 1 July 1990 and 3 0 June 1991, 16.0% of patients aged 75 to 84 years received a thrombol ytic agent compared with 21.4% between 1 June 1993 and 30 September 19 94 (a 33.8% relative increase in use). Among persons aged 85 years or older, the proportion of treated patients increased from 5.3% to 9.1% over this same period (a 71.7% relative increase in use). Increases in thrombolytic use were most prominent for older women. After adjustmen t for sex, diagnosis by initial electrocardiogram, electrocardiogram-b ased infarction description, time from symptom onset to hospital prese ntation, and period of the acute myocardial infarction, the odds of re ceiving a thrombolytic agent were significantly reduced for patients i n the older age groups compared with the odds for patients younger tha n age 55 years (for patients aged 75 to 84 years, the adjusted odds ra tio was 0.27 [95% CI, 0.26 to 0.28]; for patients aged 85 years or old er, the odds ratio was 0.09 [CI, 0.08 to 0.10]). Conclusions: Although older patients who have had acute myocardial infarction less commonly receive a thrombolytic agent, use of thrombolytic therapy in this pop ulation is expanding. However, substantial differences across age grou ps persist in the likelihood of receiving treatment, even after adjust ment for potentially confounding factors. Age-related differences in t hrombolytic use may not be completely explained by the degree to which older patients do not meet conventional eligibility criteria for thro mbolytic therapy.