PDW INDEX - A SIMPLE MODEL FOR THE PREDICTION OF LIVER FIBROSIS IN CHRONIC VIRAL HEPATITIS
Objective: To assess the accuracy of platelets, platelet morphological parameters, mean platelet volume (MPV) and platelet distribution width, (PDW) to diagnose advanced fibrosis.
Study Design: Validation study
Place and Duration of Study: Combined Military Hospital, Malir, from Jun 2008 to Jun 2009.
Patients and Methods: Simplelaboratory tests, aspartate aminotransferase (AST) alanine aminotransferase (ALT)platelet count and platelet morphological parameters were measured in 91 chronic viral hepatitis patients. All patients had liver biopsy performed. A new index, PDW Index was derived to detect the opposing effects of liver fibrosis on platelet count, MPV, and PDW. The predictive value of the index for advanced fibrosis (F3-F4) was assessed through descriptive statistics and area under the ROC curves.
Results: Two cut-offs were chosen to qualify different stages of fibrosis. A value of > 8.00 predicted advanced fibrosis, F3-F4, with a specificity of 94% and positive predictive value of 78%. A value of < 6.00 ruled out advanced fibrosis with a negative predictive value of 93% and a sensitivity of 82%. The area under the ROC curve for advanced fibrosis was 0.840. PDW Index values outside of these cut-offs correctly classified 60% of patients.
Conclusion: A simple index comprising platelet as only parameters have high diagnostic value for the advanced stages of fibrosis.