Gestational age–stratified analysis of HALP score and complete blood count–derived inflammatory indices in retinopathy of prematurity

To evaluate the temporal profile and discriminative performance of the hemoglobin–albumin–lymphocyte–platelet (HALP) score and complete blood count (CBC)-derived inflammatory indices for retinopathy of prematurity (ROP), with analyses stratified by gestational age. This retrospective single-center cohort study included 139 preterm infants born at ≤ 32 weeks of gestation who were admitted to the neonatal intensive care unit of Malatya Training and Research Hospital, Türkiye, between May 2022 and December 2025. Infants were stratified into ≤ 30-week and 30–32-week gestational age groups. CBC parameters obtained during the early postnatal period (days 2–4) and, when available, at postnatal month 1 (days 28–32) were analyzed. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), aggregate index of systemic inflammation (AISI), and HALP score were calculated. Comparisons were performed according to ROP status within gestational age strata. Discriminative performance was evaluated using receiver operating characteristic (ROC) analysis, and associations with ROP were examined using logistic regression adjusted for gestational age and birth weight. ROP developed in 30 infants (21.6%), including 10 requiring treatment. The ≤ 30-week group had a higher incidence of ROP than the 30–32-week group. Early postnatal inflammatory indices were not associated with ROP. At postnatal month 1, infants born at ≤ 30 weeks who developed ROP had lower albumin and LMR values, together with higher SII, SIRI, AISI, and NLR values, with ROC AUCs ranging from 0.73 to 0.82. After adjustment for gestational age and birth weight in all infants with available month-1 data ( n = 86; 30 ROP events), significant associations with ROP persisted for SII, SIRI, NLR, LMR, and neutrophil count. HALP score and PLR demonstrated limited discriminative performance. Interpretation of month-1 findings in the 30–32-week group was limited because of substantial missing follow-up data. In this cohort, CBC-derived inflammatory indices measured at postnatal month 1 were more discriminative than early postnatal measurements, particularly among infants born at ≤ 30 weeks of gestation. These findings suggest that selected inflammatory indices may serve as adjunctive biomarkers for ROP risk assessment in very preterm infants; however, external validation in larger prospective multicenter studies is required before clinical implementation. Not applicable.