Influence of meteorological changes on the occurrence of cerebral aneurysm rupture in the Montpellier region: A retrospective study.

Background/context: Aneurysmal subarachnoid hemorrhage (aSAH) is a sudden and potentially serious event. Recognized risk factors of aSAH include smoking, high blood pressure, and alcohol consumption. Some studies have reported associations between risk of aSAH and climatic conditions, but no consensus exists. This study aimed to investigate the association between aSAH and meteorological conditions.

Methods: We retrospectively included patients admitted for aSAH at Montpellier University Hospital between 2018-2022. We analyzed the correlation between the occurrence of aSAH and several meteorological factors, including precipitation, temperature, barometric pressure, wind speed, humidity, sunshine duration, and storms, within 24 h and 7 days before symptom onset. We collected meteorological data for days without aSAH cases as controls. A multivariate logistic regression with 10-block cross-validation and a penalty lasso method was performed.

Results: For the 5-year period, 492 patients were analyzed. Incident cases per month in this period was higher in February and August and the highest in winter. Diagnoses were made predominantly between noon and midnight. The multivariate model based on 9 weather variables on the days preceding the aSAH event had an accuracy of 0.55. The area under the curve was 0.58 (95% CI 0.55-0.62). The barometric pressure was similar between aSAH days and the mean of the 5 preceding days.

Conclusion: Due to the low accuracy of the statistical model, our study could not provide evidence of a link between weather variables and occurrence of aSAH. This issue requires further investigation and reliable epidemiological data to fully understand the pathophysiology and real impact of weather on aSAH.