Influences of hyperlipidemia history on stroke outcome; a retrospective cohort study based on the Kyoto Stroke Registry

BACKGROUND Although hyperlipidemia is known as a risk factor of stroke, its effects on the outcome are unknown. The aim of the study is to clarify the influences of hyperlipidemia on the stroke early outcome by estimating odds ratio (OR) for sequelae requiring care and hazard ratio (HR) for death. METHODS A total of 12617 stroke patients registered in the Kyoto Stroke Registry with information on a hyperlipidemia history. We compared patients who had hyperlipidemia history and patients who hadn't. The OR for remaining sequelae requiring certain care on 30 day after stroke was calculated using a logistic regression in stroke as a whole and in each stroke subtype; cerebral infarction (CI), cerebral hemorrhage (CH) and subarachnoid hemorrhage (SAH). The HR for death within 30 day after stroke was estimated by the Cox regression. RESULTS The OR (95% confidence interval) for remaining sequelae 30 days after stroke was 0.66 (0.60-0.73, p < 0.001) in patients with hyperlipidemia history compared with patients without hyperlipidemia history. After stratified by stroke subtypes, it was 0.75 (0.67-0.85, p < 0.001) in CI, 0.59 (0.45-0.77, p < 0.001) in CH and 0.77 (0.43-1.38, p = 0.767) in SAH. The HR (95% confidence interval) for death was 0.39 (0.31-0.48, p < 0.001) in patients with hyperlipidemia history comparing patients without hyperlipidemia history. After stratified by stroke subtypes, it was 0.45 (0.32-0.63, p < 0.001) in CI, 0.64 (0.44-0.93, p = 0.018) in CH and 0.76 (0.47-1.23, p = 0.264) in SAH. Each value was adjusted for age and sex. CONCLUSIONS This study suggests that the outcome is favorable for patients with hyperlipidemia history in terms of both remaining sequelae and HR for death. A factor which increases the incidence of the disease could influence on the severity of the disease in a favorable way.