Prognostic impact of systemic immune-inflammation index in patients with acute decompensated heart failure with preserved ejection fraction -PURSUIT-HFpEF Registry-

Abstract Background Systemic inflammation has been implicated in the pathophysiology of heart failure with preserved ejection fraction. Several studies have shown that systemic immune-inflammation index (SII), a novel index based on platelets, neutrophils, and lymphocytes, predicts poor prognosis in patients with cardiovascular disease. However, it remains to be elucidated whether SII could have predictive value in patients with acute decompensated heart failure with preserved ejection fraction (ADHF-HFpEF). Purpose This study is designed to investigate the association of SII at admission or discharge with poor clinical outcome in patients with ADHF-HFpEF. Methods Patients’ data were extracted from The Prospective mUlticenteR obServational stUdy of patIenTs with Heart Failure with Preserved Ejection Fraction (PURSUIT HFpEF) study, which is a prospective multicenter observational registry for ADHF-HFpEF in a city. Laboratory data and body weight measurements were performed just before discharge. We analyzed 966 patients (mean age: 81 years old, male: 45%) after exclusion of patients on dialysis, missing follow-up data, or missing data to calculate SII. SII was calculated as follows: SII = platelet count × neutrophil count / lymphocyte count on admission and at discharge. The primary endpoint was the composite of all-cause death and rehospitalization for worsening heart failure. Results During a mean follow-up period of 1.8±1.3 years, the primary endpoint was observed in 435 patients (259 patients died and 176 patients underwent rehospitalization for worsening heart failure). In multivariate Cox analysis, high SII at discharge (> 536×109 determined by receiver operating characteristic curve analysis (AUC: 0.564 [0.526-0.602]) was significantly independently associated with not only the primary endpoint (hazard ratio 1.28 [1.04-1.57], p=0.020) but also all-cause death ((hazard ratio 1.39 [1.06-1.81], p=0.018) after adjustment for major confounders such as age, gender, body mass index, NYHA class, systolic blood pressure, heart rate and laboratory data including NT-proBNP and CRP. However, high SII on admission was not significantly associated with primary endpoint after multivariate adjustment. Kaplan-Meier analysis revealed that patients with high SII at discharge had significantly greater risk of both the primary endpoint (56% vs 43%, p<0.001) and all-cause mortality than those with low SII (36% vs 24%, p<0.001). Conclusion Systemic immune-inflammation index at discharge, but not on admission, would be associated with post-discharge poor outcome in patients with acute decompensated heart failure with preserved ejection fraction.