Association of coexisting chronic hepatitis C and type 2 diabetes with insulin resistance and inflammatory profiles in a Congolese population

Abstract Background The clinical intersection between chronic hepatitis C virus (HCV) infection and type 2 diabetes (T2D) remains poorly characterized in Central Africa. This study evaluated the independent and combined associations of chronic HCV and T2D with insulin resistance (IR) and systemic inflammatory biomarker profiles among clinical cohorts in the Republic of the Congo. Methods A cross-sectional observational study was conducted involving 360 participants stratified into three groups: Group I (isolated T2D, n=240), Group II (isolated chronic HCV, n=100), and Group III (coexisting HCV and T2D, n=20). Fasting plasma glucose, fasting insulin, high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were measured. HOMA-IR was calculated using the conventional mass-unit formula adjusted for glucose in g/L. Inter-group statistical comparisons were executed using Kruskal-Wallis tests followed by Dunn’s post-hoc tests with Bonferroni correction. Results Following strict recalculation of the metabolic parameters, the corrected median HOMA-IR score was significantly higher in the comorbid Group III (7.11) compared to Group I (5.43) and Group II (1.98) (P < 0.001). The true frequency of insulin resistance (defined as HOMA-IR ≥ 2.5) was 95.0% (95% CI: 75.1–99.9) in Group III, 84.6% in Group I, and 31.0% in Group II. Within the HCV clinical sample, T2D coexisted in a proportion of 16.7% (20/120). Systemic inflammatory markers (hs-CRP, IL-6, and TNF-α) displayed a parallel significant elevation in the presence of dual pathology, demonstrating a strong continuous correlation with HOMA-IR adjustments. Conclusion In this Congolese population, the coexistence of chronic hepatitis C and type 2 diabetes is strongly associated with an aggravated profile of insulin resistance and heightened systemic inflammation compared to either condition alone. These findings underscore the need for systematic metabolic surveillance in patients presenting with dual clinical presentations.