Solar term peak of onset and death in 1 597 patients with acute ischemic stroke Circular statistical analysis

BACKGROUND： Previously, time data were analyzed by using constituent ratio or relative ratio; however, circular statistical analysis could exactly provide average peak phase of diseases. OBJECTIVE： To investigate the correlation of solar term peak with onset and death of acute ischemic stroke. DESIGN： Retrospective case analysis. SETTINGS： Emergency Department of Foshan Municipal Hospital of Traditional Chinese Medicine; Department of Science and Education, the Second People＇s Hospital of Foshan. PARTICIPANTS： A total of 1 597 patients with acute ischemic stroke were selected from Emergency Room, Department of Neurology, Foshan Municipal Hospital of Traditional Chinese Medicine from 1994 to 2002. There were 875 males and 722 females, and their ages ranged from 33 to 97 years. All cases met the diagnostic criteria of acute cerebral infarction modified by the Second National Cerebrovascular Disease Academic Meeting; meanwhile, they were diagnosed with CT/MRI test. Patients and their relatives provided the confirmed consent. METHODS： Solar term of onset was retrospectively analyzed in 1 597 patients with acute ischemic stroke; among them, solar term of death in 90 cases were analyzed by using circular statistical analysis to calculate peak phase of onset and death of acute ischemic stroke and investigate the correlation of solar term with onset and death of acute ischemic stroke. MAIN OUTCOME MEASURES： Onset and death time of patients with acute ischemic stroke. RESULTS： Solar term of onset in 1 597 patients, especially solar term of death in 90 patients, was not concentrated （P 〉 0.05）, and specific peak phase was not found out. Acute ischemic stroke low attacked from vernal equinox to summer begins, but death caused by acute ischemic stroke high attacked from grain buds to autumn begins. CONCLUSION： Patients with acute ischemic stroke do not have specific solar term peak of onset and death.