Seasonal Changes in Hospital Admissions for Pulmonary Embolism in Metropolitan Areas of Tokyo (from the Tokyo Cardiovascular Care Unit Network)

Although several studies have shown the relation between temperature/atmospheric pressure and pulmonary embolism (PE), their results are inconsistent. Furthermore, diurnal temperature range (DTR) and diurnal pressure range (DPR) were not fully evaluated for their associations with hospital admissions for PE. Study subjects comprised cases of 1,148 PE treated at institutions belonging to the Tokyo Cardiovascular Care Unit Network from January 2005 to December 2012. Patient data were combined with a variety of daily local climate parameters obtained from the Japan Meteorological Agency. Every 1°C increase in the DTR at lag0 corresponded to an increased relative risk of hospital admission for PE (odds ratio [OR] 1.036, 95% confidence interval [CI] 1.003 to 1.070). In the cooler season (November to April), an increase of 1 hPa (barometric pressure) in the DPR at lag4 and lag5 was associated with an increased relative risk of hospital admission for PE (OR 1.042, 95% CI 1.007 to 1.077 and OR 0.952, 95% CI 0.914 to 0.992, respectively). An increase in the PE hospitalization rate was seen only in the cool season. Using a metropolitan database, we showed that DTR and DPR have different impacts on hospital admissions for PE. In conclusion, we found that an increase in the DTR increases the PE hospitalization rate, especially during the cooler season. The impact of DTR and DPR on PE incidence and related hospitalizations needs to be further evaluated.