Association of Complete Blood Count -Derived Inflammatory Markers Indices with Renal Function in Patients with Chronic Kidney Disease: A Case–Control Study from Basrah, Iraq

Abstract

Chronic kidney disease (CKD) is defined as progressive deterioration of renal function, with persistent activation of inflammatory pathways contributing to disease progression and complications. Although traditional inflammatory markers are useful, their routine application is often limited by high costs and accessibility issues. Recently, complete blood count (CBC)-derived inflammatory indices, including neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI), have emerged as simple, inexpensive, and readily available biomarkers of systemic inflammatory status. However, the relationship between these indices and renal function across different populations remains poorly understood. This case–control study aimed to evaluate the association between CBC-derived inflammatory indices and renal function in patients with CKD. A total of 166 subjects were enrolled, comprising 78 patients with CKD and 88 healthy controls. Routine hematological parameters, serum urea, creatinine, and estimated glomerular filtration rate (eGFR) were assessed, and inflammatory indices were calculated from CBC-derived data. Statistical tests were used to compare groups, while Spearman correlation and multivariable linear regression analyses were employed to explore associations between indices and kidney function. Serum levels of urea, creatinine, NLR, and SIRI were significantly higher in CKD patients compared to healthy controls, whereas eGFR values were markedly decreased (all P < 0.001). eGFR showed strong inverse correlations with creatinine and urea, as well as significant negative associations with NLR and SIRI. Conversely, SII did not differ significantly between groups (P > 0.05); however, in multivariable analysis, SII remained independently associated with eGFR, suggesting a potential relationship with renal function beyond group-level differences. Among the evaluated inflammatory indices, SIRI demonstrated the most consistent and robust association with impaired renal function. These findings suggest that CBC-derived inflammatory indices, particularly SIRI, may serve as affordable and accessible biomarkers for assessing systemic inflammation and renal dysfunction in CKD. When integrated with conventional renal parameters, they could enhance clinical risk assessment and disease monitoring. Nevertheless, further validation through large-scale, multicenter prospective studies is warranted to confirm these findings and establish their clinical utility.