Association of the HALP score with disease activity in ankylosing spondylitis: a comparative analysis with inflammatory markers

Background The hemoglobin, albumin, lymphocyte, and platelet (HALP) score is a biomarker reflecting systemic inflammation and immunonutritional status. This study aimed to investigate the relationship between HALP score and disease activity in patients with ankylosing spondylitis (AS) and compare its performance with inflammatory markers. Methods This retrospective cross-sectional study included 105 patients with AS and 93 age- and sex-matched healthy controls. Disease activity was assessed using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score based on C-reactive protein (ASDAS-CRP). HALP score was calculated from hemoglobin, albumin, lymphocyte, and platelet values. Correlation, logistic regression, and receiver operating characteristic (ROC) analyses evaluated the association between HALP and disease activity. Results The HALP score was significantly lower in patients with AS than in healthy controls (p=0.002) and decreased across increasing ASDAS-CRP activity groups (p<0.001). HALP demonstrated an AUC of 0.768 (95% CI: 0.667–0.869) for ASDAS-CRP-defined activity and 0.723 (95% CI: 0.623–0.823) for BASDAI-defined activity. In multivariable analyses, HALP remained significantly associated with active disease using both ASDAS-CRP (OR=0.958, 95% CI: 0.932–0.983, p=0.001) and BASDAI (OR=0.962, 95% CI: 0.941–0.984, p=0.001). Conclusion HALP may serve as an objective and inexpensive biomarker associated with disease activity in AS. The consistent associations observed using both ASDAS-CRP and BASDAI support its potential clinical utility, although further studies are needed to validate these findings.