Prognostic implications of systemic immune-inflammation index in myocardial infarction patients with and without diabetes: insights from the NOAFCAMI-SH registry

Abstract

Background: It is well-known that systemic inflammation plays a crucial role in the pathogenesis and prognosis of acute myocardial infarction (AMI). The systemic immune-inflammation index (SII, platelet × neutrophil/lymphocyte ratio) is a novel index that is used for the characterization of the severity of systemic inflammation. Recent studies have identified the high SII level as an independent predictor of poor outcomes in patients with AMI. We aimed to investigate the prognostic implications of SII in AMI patients with and without diabetes mellitus (DM).

Methods: We included 2111 patients with AMI from February 2014 to March 2018. Multivariable Cox regression analyses were performed to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of all-cause death and cardiovascular (CV) death. Multiple imputation was used for missing covariates.

Results: Of 2111 patients (mean age: 65.2 ± 12.2 years, 77.5% were males) analyzed, 789 (37.4%) had DM. Generalized additive model analyses showed that as the SII increased, the C-reactive protein and peak TnT elevated while the LVEF declined, and these associations were similar in patients with and without DM. During a median of 2.5 years of follow-up, 210 all-cause deaths and 154 CV deaths occurred. When treating the SII as a continuous variable, a higher log-transformed SII was significantly associated with increased all-cause mortality (HR: 1.57, 95%CI: 1.02-2.43) and CV mortality (HR: 1.85, 95%CI 1.12-3.05), and such an association was also significant in the diabetics (HRs and 95%CIs for all-cause death and CV death were 2.90 [1.40-6.01] and 3.28 [1.43-7.57], respectively) while not significant in the nondiabetics (Pinteraction for all-cause death and CV death were 0.019 and 0.049, respectively). Additionally, compared to patients with the lowest tertiles of SII, those with the highest tertiles of SII possessed significantly higher all-cause mortality (HR: 1.82, 95%CI 1.19-2.79) and CV mortality (HR: 1.82, 95%CI 1.19-2.79) after multivariable adjustment, and this relationship remained pronounced in the diabetics (HRs and 95%CIs for all-cause death and CV death were 2.00 [1.13-3.55] and 2.09 [1.10-3.98], respectively) but was not observed in the nondiabetics (HRs and 95%CIs for all-cause death and CV death were 1.21 [0.75-1.97] and 1.60 [0.89-2.90], respectively). Our restricted cubic splines analyses indicated a pronounced linear association between SII and mortality only in diabetics.

Conclusions: In AMI patients with DM, high SII is an independent predictor of poor survival and may be helpful for patient's risk stratification.

Keywords: Diabetes; Generalized additive model; Myocardial infarction; Restricted cubic spline; Systemic immune-inflammation index.

Conflict of interest statement

The authors declare that they have no competing interests.0 bcv

© 2024. The Author(s).

Figures

Fig. 1

Flowchart of patient inclusion and exclusion for this study. AMI, acute myocardial infarction

Fig. 2

Associations of systemic immune-inflammation index (SII) with inflammation, myocardial injury, and cardiac function assessed with GAM. The generalized additive models (GAM) show a nearly linear association between the log-transformed SII level and CRP, peak TnT, and LVEF levels in the overall cohort, and in the diabetic and nondiabetic cohorts, respectively. The 95% confidence intervals are in shading. The navyblue dots indicate the whole cohort, and the green and red dots indicate the diabetic and nondiabetic cohorts, respectively. CRP C-reactive protein, LVEF left ventricular ejection fraction

Fig. 3

Primary and secondary endpoints. Long-term all-cause mortality and CV mortality in the whole cohort (A, D), and in the diabetic (B, E), and nondiabetic (C, F) cohorts according to the tertiles of SII level, respectively. CV cardiovascular

Fig. 4

Hazard ratios (HRs) for all-cause death and CV death by SII on a continuous scale in the whole cohort, and in the diabetic and nondiabetic cohorts. HRs with 95%CIs for all-cause death and CV death, accounting for SII on a continuous scale, are from Cox regression restricted cubic splines (RCS). Orange areas show the distribution of SII levels. The solid red line in each figure indicates the HR, and the dashed red lines indicate the 95%CI. Covariates in the multivariable RCS model included: age, sex, current smoker, comorbidities (hypertension, diabetes, dyslipidemia, CKD, heart failure, myocardial infarction), STEMI, Killip > I, primary PCI, peak TnT, CRP, serum creatinine, LVEF, as well as medications (aspirin, ACEI/ARB/ARNI, β-blocker). CKD chronic kidney disease, PCI percutaneous coronary intervention