Seasonal variations and prognosis of patients with sepsis, septic shock, and cardiogenic shock

Background The study sought to investigate seasonal effects on the prevalence and outcomes of patients with cardiogenic shock (CS) and sepsis/septic shock (SS).Methods We analyzed two prospective single-center registries at a tertiary medical ICU including patients with CS (June 2019–May 2021) and sepsis/SS (June 2019–January 2021). Patients were grouped by season of ICU admission (spring, summer, autumn, winter). The primary endpoint of 30-day all-cause mortality was investigated using Kaplan–Meier and multivariable Cox regression analyses.Results We included 634 patients: 273 CS (43.1%) and 361 sepsis/SS (56.9%). CS admissions clustered in winter/autumn (63.4% of CS cases), whereas sepsis/SS admissions were highest in spring (78; 34.4%), followed by autumn (61; 26.9%). Baseline demographics were broadly similar by season. In CS, use of organ support was stable; however, in-hospital cardiac arrest presentations were more frequent in summer (p = 0.015). In sepsis/SS, summer and winter admissions showed higher acuity with more invasive ventilation (p = 0.025), higher norepinephrine dose, and higher admission lactate levels (p = 0.030). Overall, 30-day mortality was 53.5% and ICU mortality was 51.6%, with no differences when stratified by the season of admission both in CS and SS patients. Even after multivariable adjustments, the risk of short-term all-cause mortality was not affected by the season of admission in CS (adjusted HR (reference: spring): summer 1.454, autumn 1.460, winter 1.435; all p > 0.05) and SS (adjusted HR (reference: spring): summer 0.976, autumn 1.183, winter 0.949; all p > 0.05).Conclusion The season of admission did not impact 30-day all-cause mortality in patients with CS or sepsis/SS.