Apelin and CGRP as diagnostic biomarkers in coronary artery disease: a case–control study

Abstract

Background & objective: Coronary artery disease (CAD) remains a major cause of global morbidity and mortality. Among the regulatory peptides involved in vascular homeostasis, apelin and calcitonin gene–related peptide (CGRP) play critical roles in vasodilation, endothelial protection, and cardiac function, highlighting their potential value as diagnostic biomarkers. This study aimed to evaluate the diagnostic utility of serum apelin and CGRP levels in patients with CAD.
Methods: A total of 90 male participants were enrolled in this case–control study, including 45 CAD patients and 45 age-matched healthy controls. Routine biochemical parameters were assessed using standard colorimetric assays, while serum apelin and CGRP levels were measured using ELISA. Anthropometric indices and atherogenic ratios were calculated using standard formulas .
Results: CAD patients demonstrated significantly higher levels of triglycerides, total cholesterol, LDL, VLDL,
atherogenic indices (AIP, AC, CRI-I, CRI-II), troponin, CRP, calcium, and body fat percentage, while HDL, magnesium, apelin, and CGRP levels were markedly reduced (P < 0.001). ROC analysis showed that apelin exhibited excellent diagnostic accuracy with an AUC of 0.894 and an optimal cutoff of 2.98 ng/mL (sensitivity: 88.9%; specificity: 82.2%). CGRP showed moderate diagnostic performance, with an AUC of 0.691 and a cutoff of 30.5 pg/mL.
Conclusion: Reduced serum apelin and CGRP levels are strongly associated with CAD, with apelin demonstrating superior diagnostic value compared to CGRP. Apelin may serve as a promising independent biomarker for early CAD detection. Further large-scale studies are recommended to validate its clinical applicability.
Abbreviations: CAD-coronary artery disease; T2DM-type2 diabetes mellitus; ACS- acute coronary syndrome; HDL – high-density lipoprotein; TG - triglyceride; BMI - body mass index; SBP - systolic blood pressure; DBP - diastolic blood pressure; CRP- C-reactive protein; BF%-Body fat percentage; BMP7-Bone Morphogenetic Protein 7; TRPM7- Transient Receptor Potential Melastatin 7.
Keywords: CRI. Apelin. CRP. Troponin. WHtR.
Citation: Makki NF, Khalil MM. Apelin and CGRP as diagnostic biomarkers in coronary artery disease: a case–control study. Anaesth. pain intensive care 2026;30(1):55-61. DOI: 10.35975/apic.v30i1.3102
Received: December 19, 2025; Revised: December 26, 2025; Accepted: January 01, 2026