Evaluation of serum dipeptidyl-peptidase-like protein 6 (dppx) levels in patients with epilepsy: a case control study from Al Diwaniyah governorate, Iraq

Abstract

Objective: To compare serum DPPX levels between epilepsy patients and healthy controls, evaluate its diagnostic performance via ROC analysis, and assess associations with disease duration.

Methods: A hospital-based case-control study (Nov 2025–Mar 2026) included 50 epilepsy patients (18–75 years, both sexes, ≥1 year of aware/impaired awareness seizures) and 50 age-/sex-matched healthy controls. Exclusion criteria: diabetes, chronic diseases, autoimmune disorders, cancer, pregnancy, lactation. Serum DPPX measured by ELISA. Statistical analysis used SPSS v26 (t-test, chi-square, ROC). Significance: p≤0.05.

Results: Mean age was similar between patients (33.24±8.31 years) and controls (32.18±7.11 years; p=0.681). Serum DPPX was significantly lower in epilepsy patients (47.02±4.33 vs. 83.68±7.38 ng/mL; p=0.001). ROC analysis yielded an optimal cut-off <46.69 ng/mL (AUC=0.721, 95% CI: 0.623–0.819; p=0.001), sensitivity 70.0%, specificity 74.0%, PPV 72.9%, NPV 71.2%. No significant DPPX difference between disease duration ≤10 years (45.16±6.48 ng/mL) and >10 years (48.49±5.92 ng/mL; p=0.707).

Conclusion: Serum DPPX is significantly reduced in epilepsy patients, showing modest discriminatory value that remains stable across disease duration. It may serve as a potential adjunct biomarker. Larger prospective studies with epilepsy subtype stratification are warranted.