The Systemic Immune-Inflammation Index Predicts Long-Term Outcomes in Patients With Unstable Angina and Diabetes...

The incidence of unstable angina (UA), a type of cardiovascular disease (CVD), has increased in recent years. Meanwhile, timely percutaneous coronary intervention (PCI) or percutaneous transluminal coronary angioplasty (PTCA) procedures are crucial for patients with UA who also have diabetes mellitus (DM). Additionally, exploring other factors that may influence the prognosis of these patients could provide long-term benefits. The systemic immune-inflammation index (SII), a novel marker for assessing inflammation levels, has been shown to correlate with the long-term prognosis of various diseases. Thus, this study aimed to investigate the predictive value of the SII for the long-term prognosis of patients with UA and DM after revascularization.

A total of 937 UA patients who underwent revascularization, of which 359 also had DM, were included in this study. Patients were divided into two groups: the low SII group (<622.675 × 10⁹/L; n = 219, 61.0%) and the high SII group (≥622.675 × 10⁹/L; n = 140, 39.0%). The primary outcome was the frequency of major adverse cardiovascular and cerebrovascular events (MACCEs). The secondary outcome was the incidence of all-cause death.

Of the 359 patients who visited our institution between January 2018 and January 2020, 23 patients (10.5%) in the low SII group experienced MACCEs, whereas 34 cases (24.3%) in the high SII group experienced MACCEs, showing a statistically significant difference (p < 0.001). After conducting univariate and multivariate regression analyses on the endpoint events, we identified several risk factors for MACCEs. These risk factors included high SII levels, a history of myocardial infarction (MI), prior PCI or coronary artery bypass grafting (CABG), elevated brain natriuretic peptide (BNP), and the lack of angiotensin-converting enzyme inhibitors (ACEI) or statin use. Upon adjusting for covariates including age, sex, body mass index (BMI), BNP, smoking, hypertension, PCI or CABG history, MI history, statin use, ACEI use, and the presence of three-vessel coronary disease, only high SII levels remained a risk factor for MACCEs (HR: 0.155, 95% CI: 0.063-0.382; p = 0.001). However, high SII levels were not identified as a risk factor for other individual endpoint events, including non-fatal stroke, cardiovascular death, non-fatal MI, or cardiac rehospitalization.

Elevated SII levels following percutaneous intervention are associated with poor outcomes in patients with UA and DM. Therefore, regular monitoring and controlling inflammation levels may help improve long-term outcomes.