Fig. 3

Mediation analysis with age ≥ 70 years as independent predictor, the individual comorbidities as mediator and in-hospital mortality as outcome. All comorbidities partly mediated the effect of age on in-hospital mortality (all p-values < 0.001). The mediation effect was 5% (95% CI 2–9%) for hypertension, 3% (95% CI 2–4%) for diabetes mellitus, 3% (95% CI 0.4–6%) for dyslipidemia, 5% (95% CI 3–7%) for chronic kidney disease, 2% (95% CI 1–3%) for COPD, and 5% (95% CI 2–9%) for history of cardiac disease. COPD = chronic obstructive pulmonary disease