Diagnostic value of platelet count and platelet indices in assessing inflammatory bowel disease activity in children

Objective. To analyze the connection between the complex of platelet indices in complete blood count test with the clinical and endoscopic activity scores for Crohn's disease (CD) and ulcerative colitis (UC) in pediatric patients and to determine their most informative threshold values. Patients and methods. In this study, 370 children aged 5 to 18 years with diagnosed CD (n = 150) and UC (n = 220) were examined. The clinical activity of UC was assessed according to PUCAI, CD – according to PCDAI; the assessment of endoscopic activity in children with UC was carried out according to UCEIS and CD – according to SES-CD. The study included platelet indices of 630 complete blood count tests (270 in patients with CD and 360 in patients with UC): platelet count (PLT), mean platelet volume (MPV), platelet large cell ratio (P-LCR) and platelet distribution width (PDW). Results. Increased platelet count and decreased platelet indices were noted as the clinical and endoscopic activity of CD and UC in children increased. A positive correlation between the clinical and endoscopic activity indices in inflammatory bowel diseases and platelet count and negative correlations with platelet indices were revealed. ROC analysis showed that the informative value of platelet indices in assessing the endoscopic activity of CD and UC is higher than in assessing the clinical activity. The optimal threshold values for platelet count (cut-off) for determining the endoscopic activity of CD and UC were 340 × 109/L and 350 × 109/L (Se 77%, Sp 69% and Se 63%, Sp 67%, respectively). The specificity of determing the endoscopic activity of 99% was obtained for platelet count of 459 × 109/L and 390 × 109/L for CD and UC, respectively. In children with CD, the indicators MPV <7.8 fL, PDW <7.25 fL, P-LCR <15.2% characterized the presence of endoscopic disease activity with 99% specificity; in children with UC, the specificity of determining the endoscopic activity of 99% was obtained for MPV <9.25 fL, PDW <9.85 fL, P-LCR <17.5%. Conclusion. An increase in platelet count and a decrease in platelet indices (MPV, PDW and P-LCR) can be surrogate markers of endoscopic activity of these diseases. The established threshold values will improve the accuracy of diagnosing the activity of inflammatory bowel diseases in children. Key words: Crohn's disease, ulcerative colitis, platelets, platelet indices, clinical activity, endoscopic activity