Seasonal variation of clinical characteristics and prognostic of adult patients admitted to an intensive care unit.

Objective: To evaluate seasonal variations of clinical characteristics, therapeutic resource use, and outcomes of critically ill patients admitted to an intensive care unit.

Methods: A retrospective cohort study conducted from January 2011 to December 2016 in adult patients admitted to the intensive care unit (ICU) of a University Hospital. Data were collected on the type of admission, APACHE II, SOFA, and TISS 28 scores at ICU admission. Length of hospital stay and vital status at hospital discharge were recorded. A significance level of 5% was adopted.

Results: During the study period, 3.711 patients were analyzed. Patients had a median age of 60.0 years (interquartile range = 45.0 - 73.0), and 59% were men. The independent risk factors associated with increased hospital mortality rate were age, chronic disease, seasonality, diagnostic category, need for mechanical ventilation and vasoactive drugs, presence of acute kidney injury, and sepsis at admission.

Conclusion: It was possible to observe variations of the clinical characteristics and prognosis of patients; summer months presented a higher proportion of clinical and emergency surgery patients, with higher mortality rates. Sepsis at ICU admission did not show seasonal behavior. A seasonal pattern was found for mortality rate.