Abstract W P78: Effect of Weather Patterns on the Admission and Outcome of Intracranial Aneurysms

Abstract

Introduction: There have been speculations that regional weather patterns play a role in the rupture of cerebral aneurysms, although the literature has been scarce and inconsistent. Furthermore, there are no studies analyzing the effect of weather patterns on the outcome of ruptured aneurysms. The purpose of this study was to use a nationwide sample to analyze the effects of temperature, precipitation, daily sunlight and relative humidity on hospital admission rate and outcome of ruptured aneurysms. Methods: Patients were identified using the Nationwide Inpatient Sample (2001-2010) by ICD-9 codes for subarachnoid hemorrhage or intracerebral hemorrhage and a procedural code for aneurysm repair. Climate data were obtained from the State of the Climate Report 2010 released by the National Climatic Data Center. Multivariate regression models were used to analyze the effects of average monthly temperature, precipitation, percent possible sunlight and relative morning humidity on monthly hospital admission, in-hospital mortality and non-routine discharges, adjusted for state population in million obtained from US Census 2010. Patients were stratified by sex and age (</>60) to study the effects of weather patterns on the subgroups. Results: Over the 10-year period, a total of 16970 hospitalizations were included from 723 hospitals across 41 states. Low daily sunlight and relative humidity were associated with increased admission of ruptured aneurysms ( p<0.001 and p<0.001) but had no effect on in-patient mortality or non-routine discharges. Low precipitation was associated with higher mortality ( p=0.005 ). When stratified by age, low temperature was associated with reduced admission ( p=0.023 ) and increased non-routine discharges ( p=0.009 ) in patients age>60. No difference was observed when stratified by sex. Conclusions: This is the first nationwide study to suggest that sunlight and relatively humidity are associated with admission of ruptured cerebral aneurysms and that low precipitation is associated with increased mortality. While it has been postulated that external atmospheric factors may cause hormonal and homeostatic changes, these are only speculations and further analyzes are necessary to understand this relationship.