Environmental factors are associated with hospital admissions for sepsis-related pneumonia: A bidirectional case-crossover design

Pneumonia is a common cause of morbidity and sepsis worldwide, mainly in the elderly. We evaluated the impact of short-term exposure to environmental factors on hospital admissions for sepsis-related pneumonia in a nationwide study in Spain.

We conducted a bidirectional case-crossover study in patients who had sepsis-related pneumonia in 2013. Data were obtained from the Minimum Basic Data Set (MBDS) and the State Meteorological Agency (AEMET) of Spain. Conditional logistic regressions were used to evaluate the association between environmental factors (temperature, relative humidity, NO₂, SO₂, O₃, PM₁₀, and CO) and hospital admissions with sepsis-related pneumonia.

A total of 3,262,758 hospital admissions were recorded in the MBDS, of which, 253,467 were patients with sepsis. Among those, 67,443 had sepsis-related pneumonia and zip code information. We found inverse associations [adjusted odds ratio (aOR) values < 1] between short-term exposure to temperature and hospital admissions for sepsis-related pneumonia. Moreover, short-term exposure to higher levels of relative humidity, NO₂, SO₂, O₃, PM₁₀, and CO were directly associated (aOR values > 1) with a higher risk of hospital admissions for sepsis-related pneumonia. Overall, the impact of environmental factors was more prominent with increasing age, mainly among the elderly aged 65 or over.

Short-term exposure to environmental factors (temperature, relative humidity, NO₂, SO₂, O₃, CO, and PM₁₀) was associated with a higher risk of hospital admissions for sepsis-related pneumonia. Our findings support the role of environmental factors in monitoring the risk of hospital admissions for sepsis-related pneumonia and can help plan and prepare public health resources.