Evaluation of systemic immune-inflammation index in young patients with coronary artery disease: association with glycaemic status

Background: Coronary artery disease (CAD) in young adults is an important health concern, particularly in India. The Systemic Immune-Inflammation Index (SII) is a composite inflammatory marker derived from platelet, neutrophil and lymphocyte counts. However, limited information is available regarding its relationship with glycaemic status in young patients with CAD. To assess the association of Systemic Immune-Inflammation Index (SII) with glycaemic status and evaluate cardiovascular risk factors, comorbidities, clinical, laboratory, biochemical and angiographic characteristics in young patients with coronary artery disease. Methods: A prospective observational study was conducted among 80 patients aged 18–45 years with CAD admitted to the Coronary Care Unit of Bangalore Baptist Hospital, Bangalore, during 2025. Demographic, clinical, laboratory, echocardiographic and angiographic data were collected. SII was calculated as platelet count × neutrophil count / lymphocyte count. Patients were grouped according to SII level and glycaemic status and the groups were compared using appropriate statistical tests. Results: The mean age was 38.6±3.6 years, with males accounting for 87.5% of participants. Smoking (53.8%), diabetes (43.8%) and hypertension (36.3%) were the most common cardiovascular risk factors. The mean SII was 1049±881. Significant differences between the SII and glycaemic groups were observed for age (p=0.039), dyslipidaemia (p=0.006), HbA1c (p<0.00001), platelet count (p=0.0003), neutrophil count (p<0.00001) and lymphocyte count (p<0.00001). Angiographic disease extent did not differ significantly between the groups (p=0.379). Conclusions: SII showed significant differences according to glycaemic status, particularly in relation to HbA1c and its cellular components. SII may provide additional information regarding systemic inflammation in young patients with CAD.