The predictive role of systemic immune-inflammation index in non-ischemic cardiomyopathy

Aims: The systemic immune-inflammation index (SII), a useful marker of systemic inflammation, has been shown to be associated with cardiovascular diseases in previous studies. Inflammation is known to have a significant role in heart failure, but no study has evaluated the relationship between inflammatory parameters and prognosis in patients with non-ischemic cardiomyopathy (NICM). This study aimed to explore the relationship between SII and long-term mortality in patients with non-ischemic cardiomyopathy. Methods: The study enrolled 326 consecutive patients with NICM. The median 25-month follow-up mortality results of the patients were recorded retrospectively. SII, a combined index based on the count of three parameters, was calculated as follows: neutrophil count x platelet count/lymphocyte count. Patients with a higher SII value than the median SII were accepted as having a high SII, and the remaining patients were defined as having a low SII. The survival curves of the patients with high and low SII values during the study period were analyzed using the Kaplan-Meier method. Results: The mean age of the participants was 46.6 years. The mean SII value was 598.4 in patients without mortality and 722.7 in those with mortality. In the multivariate logistic regression analysis, SII was found to be an independent predictor of mortality. The median SII value of the patients who participated in the study was 644. Upon dividing the patients into two groups according to the median SII value, the mortality rate was determined to be 48.4% in the high SII group and 27.4% in the low SII group. Conclusion: High SII values were observed to be associated with long-term mortality in patients with NICM. SII, which is easily accessed and simply calculated, can be used to predict mortality risk in these patients. Prospective and larger cohort studies are needed to clarify the causality of this relationship.