Validation of a Multivariate Model Predicting Presence and Size of Varices

Background A model developed by our group identified low platelets and advanced Child-Pugh class (CPC) as being associated with large varices. Goals To validate a defined cut-off of platelets ≤80,000/μL in CPC-A for large varices and platelets ≤90,000/μL in CPC-B/C for any varices. Study Validation cohorts consisted of patients with cirrhosis undergoing screening for varices from Oregon Health and Science University (n=152), Indiana University (n=252), and Genoa, Italy (n=101). Similar clinical and laboratory data were collected as for the original cohort. To assess the ability of these cut-offs to predict presence of large and any varices, sensitivity, specificity, positive and negative predictive values, likelihood ratios, and the c-statistic were measured. Results The validation cohorts were statistically different from the original cohort with regards to CPC and prevalence of large varices. Combining the original (n=301) and validation cohorts resulted in a negative predictive value of 92.1% for platelets ≤80,000/μL in CPC-A for large varices and positive predictive value of 80.1% for platelets ≤90,000/μL in CPC-B/C for any varices. Combining the 4 cohorts yielded a c-statistic of 0.67 (95% confidence interval: 063-0.72). No other factors such as splenomegaly and Model for End-Stage Liver Disease score were identified as significant. Conclusions This study confirms the validity of a previous model identifying low platelets and advanced CPC class as predictors of large varices. Despite combining the cohorts, no other risk factors were identified.