Effect of hyperthermia on prognosis after acute ischemic stroke.
OBJECTIVE
Experimental studies have shown that hyperthermia is a determinant of poor outcome after ischemic stroke. Clinical studies evaluating the effect of temperature on poststroke outcome have, however, been limited by small sample sizes. We sought to evaluate the effect of temperature and timing of hyperthermia on outcome after ischemic stroke.


METHODS
Data of 5305 patients in acute stroke trials from the Virtual International Stroke Trials Archive (VISTA) data set were analyzed. Data for temperatures at baseline, eighth, 24th, 48th, and 72nd hours, and seventh day were assessed in relation to outcome (poor versus good) based on the modified Rankin Scale at 3 months. Hyperthermia was defined as temperature >37.2 degrees C and poor outcome as 90-day modified Rankin Scale >2. Hazard ratios with 95% CIs were reported for hyperthermia in relation to the outcome. Logistic regression models, in relation to hyperthermia, were fitted for a set of preselected covariates at different time points to identify predictors/determinants of hyperthermia.


RESULTS
The average age of patients was 68.0+/-11.9 years, 2380 (44.9%) were females, and 42.3% (2233) received thrombolysis using recombinant tissue plasminogen activator. After adjustment, hyperthermia was a statistically significant predictor of poor outcome. The hazard ratios (95% CI) for poor outcome in relation to hyperthermia at different time points were: baseline 1.2 (1.0 to 1.4), eighth hour 1.7 (1.2 to 2.2), 24th hour 1.5 (1.2 to 1.9), 48th hour 2.0 (1.5 to 2.6), 72nd hour 2.2 (1.7 to 2.9), and seventh day 2.7 (2.0 to 3.8). Gender, stroke severity (National Institutes of Health Stroke Scale score >16), white blood cell count, and antibiotic use were significantly associated with hyperthermia (P< or =0.01).


CONCLUSIONS
Hyperthermia, in acute ischemic stroke, is associated with a poor clinical outcome. The later the hyperthermia occurs within the first week, the worse the prognosis. Severity of stroke and inflammation are important determinants of hyperthermia after ischemic stroke. In patients with acute ischemic stroke, aggressive measures to prevent and treat hyperthermia could improve the clinical outcomes.
Saini
Monica
M
Division of Neurology, Department of Medicine, University of Alberta, AB, Canada.
Saqqur
Maher
M
Kamruzzaman
Anmmd
A
Lees
Kennedy R
KR
Shuaib
Ashfaq
A
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D002986:Clinical Trials as Topic; D016208:Databases, Factual; D005260:Female; D005334:Fever; D005343:Fibrinolytic Agents / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D020521:Stroke / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage; D016896:Treatment Outcome
D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator