Diagnostic relevance of osteocalcin and bone alkaline phosphatase as markers of bone turnover in Sickle Cell Anaemia: A Zaria study.

BACKGROUND

Sickle cell anaemia (SCA) significantly contributes to skeletal morbidity in Nigeria, with bone complications like pain crises and avascular necrosis prevalent. Osteocalcin (OC) and bone-specific alkaline phosphatase (BALP) are potential markers of bone formation, yet their diagnostic utility in SCA is underexplored in African populations.

OBJECTIVE

To assess serum OC and BALP levels in Nigerian SCA patients during bone pain crises (BPC), steady state, and in healthy controls, evaluating their diagnostic relevance for bone turnover.

METHODS

This cross-sectional study at Ahmadu Bello University Teaching Hospital, Zaria, enrolled 180 adults (60 SCA in BPC, 60 steady state, 60 HbAA controls). Serum OC and BALP were measured via ELISA. Data were analyzed using Kruskal-Wallis tests, Spearman's correlation, and ROC curves (p≤0.05).

RESULTS

Median OC and BALP levels were significantly higher in SCA BPC (26.53 ng/mL, 23.51 µg/L) and steady state (24.40 ng/mL, 14.42 µg/L) compared to controls (16.07 ng/mL, 9.95 µg/L; p=0.022, p<0.001). BALP showed superior diagnostic accuracy (AUC=0.789, sensitivity=98.3%) compared to OC (AUC=0.592). OC correlated with BMI (p=0.020), but not age or gender.

CONCLUSION

BALP is a more reliable marker than OC for detecting bone turnover alterations in SCA, particularly during BPC, supporting its use in resource-limited settings.