Prospective validation of P2/MS noninvasive index using complete blood counts for detecting oesophageal varices in B-viral cirrhosis

Backgrounds: Periodic endoscopic screening for oesophageal varices (OVs) and prophylactic treatment for high-risk OVs (HOVs; medium/large OVs or small OVs plus red sign/decompensation) are currently recommended for all cirrhotic patients. However, if a simple, noninvasive test is available, many low-risk patients may reliably avoid endoscopy. Aims: We conducted a large-scale validation study of a simple, noninvasive test called P2/MS based on complete blood counts, (platelet count)²/[monocyte fraction (%) × segmented neutrophil fraction (%)], and compared it with other predictive tests for HOVs in B-viral cirrhotic patients. Methods: From 2008 to 2009, we prospectively enrolled 318 consecutive B-viral cirrhotic patients. All underwent endoscopy and laboratory evaluation. Results: An area under the receiver operating characteristic curve of P2/MS was 0.941 for HOVs, comparable with those of the age-spleen platelet ratio index (0.922, P=0.317) and spleen-platelet ratio index (0.922, P=0.324), and better than those of age-platelet index (0.653, P<0.001), aspartate aminotransferase (AST)-platelet ratio index (0.871, P<0.006) and AST-alanine aminotransferase ratio (0.644, P<0.001). P2/MS<11 reliably identified 83 patients as having HOVs (94.0% positive predictive value), while at a cutoff of 25 and 179 as not having HOVs (94.4% negative predictive value). Overall, P2/MS reliably determined the likelihood of HOVs in 262 patients (82.4%). These cutoffs were validated internally using bootstrap resampling methods, which showed good agreement. Conclusions: P2/MS is a simple, accurate and economical method, reducing the need for endoscopy in B-viral cirrhosis. Patients with P2/MS<11 should be considered for appropriate prophylactic treatments, while those with P2/MS>25 may avoid endoscopy reliably.