Positive association between systemic immune-inflammatory index and mortality of cardiogenic shock

Cardiogenic shock (CGS) is not only a state of hypoperfusion, but also related to inflammation. The prognostic value of systemic immune-inflammatory index (SII), an innovate biomarker of inflammation, in CGS patients has not been assessed. This study aims to explore the associations between SII and mortality in patients with CGS.

Data on patients diagnosed with CGS were extracted from MIMIC-III database version 1.4. The follow-up started on the patients' first admission to ICU. The primary outcome was 30-day mortality. 90-day and 365-day mortality were the secondary outcomes. Cox proportional hazards models were used to investigate the associations between SII and mortality of CGS patients.

707 patients with CGS were included in our study (59.8% male, 67.5% the white, 70.27 ± 14.56 years). For 30-day mortality, the HR (95% CI) value of high-SII group was 2.17 (1.60, 2.93) compared with the reference of low-SII group (P < 0.0001). The HR value of mid-SII group, however, showed none statistical significance (HR: 1.03, 95% CI: 0.74-1.43, P = 0.8516). When adjusted for age, gender and ethnicity in Model I, the adjusted HR (95% CI) value of high-SII group was 2.28 (1.69, 3.09). When further adjusted for heart rate, SBP, serum potassium, PTT, INR and ECI in Model II, the adjusted HR value of high-SII group was still statistically significant (HR: 2.08, 95% CI: 1.52-2.86, P < 0.0001). Similar results were also shown in the secondary outcomes of 90-day and 365-day mortality.

High level of SII is associated with increased short- and long-term mortality of patients with CGS. SII, a readily available biomarker, can independently predict the prognosis of CGS patients.