Abstract 3309: Enrolling the Oldest Old is Achievable in Acute Stroke Clinical Trials

Abstract

Background: Acute stroke clinical trials have frequently excluded the very elderly, leading to a lack of data regarding therapy effect in this rapidly growing population. We sought to describe the frequency and characteristics of the oldest old (patients aged 80-95) enrolled in an ongoing multicenter prehospital treatment trial, the Field Administration of Stroke Therapy-Magnesium (FAST-MAG) study. Methods: FAST-MAG is a phase 3, NIH-funded, randomized, double-blind study of field-administered magnesium sulfate vs. placebo in stroke patients enrolled within 2 hours of symptom onset. All patients who were not disabled prestroke up to age 95 are eligible for enrollment. Results: Among the first 1207 subjects enrolled in FAST-MAG, 353 (29%) were >= 80 and 42 (4%) were >= 90 years old. Compared with younger trial subjects, individuals >=80 years old had higher mean age (85 v 63, p<0.0001), were more often women (53% vs. 38%, P<0.0001), less often Hispanic ethnicity (13% v 27%, p<0.0001), more often racially white (87% v 76%, p<0.0001), and were less likely to have intracerebral hemorrhage (15% v 28%, p<0.0001). However, the very elderly had similar stroke deficit severity (NIHSS 11 v 11, p=0.65) and were evaluated by paramedics (mean 37 v 37 min) and arrived in the ED (73 v 71 min, p=0.65) at similar time points. In the field, the very elderly had similar SBP (160 v 158, p=0.59) but lower DBP (78 v 86, p<0.0001). Medical history variables distinguishing the very elderly from younger patients were higher frequency of HTN (87% vs. 77%, P<0.0001), atrial fibrillation (40% vs. 17%, p<0.0001), coronary artery disease (27% vs 18%, p<0.0001), and lower tobacco use (4% vs 23%, p<0.0001). Rates of TPA use among cerebral ischemia patients did not differ between the very elderly and younger patients (31% v 28%, p=0.507). The subgroup of extremely old patients, aged 90-95, were similar to patients aged 80-89, except there were no smokers, and even higher proportions were women (69%), non-Hispanic (91%) and white (93%). Conclusions: The very elderly can account for nearly 3 in 10 patients enrolled in a hyperacute stroke treatment trial. The oldest old have distinct clinical characteristics, indicating that their inclusion is in clinical trials is important for study results to be widely generalizable to clinical practice.