Aim:

Limited information is available on seasonal variation of cardiogenic shock. The aim of this study was to describe seasonal incidence and outcomes in cardiogenic shock.

Methods and Results:

We analyzed the impact of seasons on incidence and outcome of 441,696 cardiogenic shock patients treated from 2005 to 2017 in Germany. Data from the Federal Bureau of Statistics were used. Categorical variables are shown as frequencies and percentages and compared using the Chi² test; continuous variables are compared using the one-way analysis of variance. Patients were categorized based on admission in one of four groups: winter, spring, summer, and fall. The seasons comprised the following months: winter included the months January to March, spring April to June, summer July to September and fall October to December.

There were approximately 15,000 more patients admitted with cardiogenic shock in winter than in summer (Figure 1). Patients admitted with cardiogenic shock in winter were slightly older than in those admitted in summer (winter vs. summer, mean age 71.1 (±13.62) vs. 70.87 (±13.84), whereas sex did not differ over the seasons (p=0.81). The incidence of acute myocardial infarction, pre-hospital and in-hospital cardiac arrest in cardiogenic shock patients varied across seasons (p<0.01) and was highest in fall. 

Finally, cardiogenic shock patients had a higher in-hospital mortality in winter than summer (winter vs. summer, n=70,727 (61.12%) vs. n=62,379 (58.86%)).

Conclusion:

Seasonal variation of incidence of cardiogenic shock and in-hospital mortality were of substantial magnitude with lowest incidence and lowest mortality in the summer season. An understanding of these seasonal patterns may provide novel aspects for research in cardiogenic shock patients.

Figure 1: Seasonal trends of cardiogenic shock cases and in-hospital mortality.