The relation of C-reactive protein to vasoocclusive crisis in children with sickle cell disease

In view of evidence linking sickle cell anemia (SCA) with chronic inflammation, and given the role of high sensitivity C-reactive protein (hs-CRP) as inflammatory mediator, we hypothesized that SCA vasoocclusive crisis (VOC) is associated with heightened hs-CRP levels. Study subjects comprised 104 SCA patients who experienced VOC event during the study period (VOC group), and 40 SCA patients who did not develop VOC for at least 9 months prior to blood collection (Steady-state group). hs-CRP determination was done by latex-enhanced nephelometry. Higher hs-CRP levels were seen in VOC [median(range)=31.3(1.14-363.0)] than steady-state [median(range)=5(0.16-185.0)] groups (P<0.001), with enrichment in high hs-CRP percentiles in VOC cases, which translated into step-wise increased VOC risk. Receiver-operating characteristic (ROC) analysis was employed in assessing the usefulness of hs-CRP as predictor of the frequency and severity of VOC. Spearman's correlation coefficient between hs-CRP and VOC was 0.65 (P<0.001) among unselected patients (0.71 in males and 0.59 in females). hs-CRP area under ROC curves was 0.90 (95% CI=0.85-0.94) among unselected patients, 0.94 (95% CI=0.89-0.98) for males, and 0.85 (95% CI=0.77-0.93) for females. Logistic regression analysis confirmed the positive association of increased hs-CRP levels with VOC, which correlated positively with VOC frequency (P<0.001), type (P<0.001), pain (P<0.001), and need for hospitalization (P=0.024). These data support strong association of increased hs-CRP levels with VOC, which impacts VOC-related parameters, and support a role for hs-CRP in VOC follow-up.