Utility of Platelet Count for Predicting Cirrhosis in Alcoholic Liver Disease: Model for Identifying Cirrhosis in a US Population.

BACKGROUND

Thrombocytopenia has been shown to be the single most useful laboratory investigation for identifying subclinical cirrhosis of varying etiologies. However, alcohol per se can result in thrombocytopenia, and hence it is unclear whether platelet count can identify cirrhosis in patients who are alcoholic.

OBJECTIVES

To characterize the utility of clinical predictors, especially platelet count, for identifying the presence of cirrhosis in alcoholics. To develop a simple, objective model for identifying cirrhosis in alcoholics.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 2,471 consecutive hospitalized patients with abnormal liver enzyme levels were screened, from which 272 patients with a history of recent and ongoing alcohol intake, negative diagnostic studies for alternative etiologies of chronic liver disease, and recent liver imaging with ultrasound or CT scan were included.

MAIN MEASURES: Results of liver imaging and admission laboratory studies including liver enzymes, coagulation studies, and blood counts.

KEY

RESULTS

One hundred twenty-nine patients (47%) had cirrhosis based on imaging; 143 patients (53%) had no cirrhosis. A pre-sobriety platelet count (during ongoing alcohol intake) of less than 70*10(3) cells/mm(3) was effective for ruling in cirrhosis (positive likelihood ratio [LR] 6.8, 95% CI: 3.4, 14); platelet count greater than 200*10(3) was useful for ruling out cirrhosis in alcoholics (negative LR 0.18, 95% CI: 0.10, 0.35). Multivariate logistic regression analysis identified international normalized ratio (INR) (p < 0.01) and pre-sobriety platelet count (p < 0.01) as independent predictors of cirrhosis. A Model for identifying Cirrhosis in Alcoholic Liver Disease (MCALD) was developed using the INR and pre-sobriety platelet count; it had an area under the receiver operating characteristic curve of 0.89 and Hosmer-Lemeshow goodness of fit chi(2) (p value) of 8.9 (0.35) for predicting cirrhosis in alcoholics. A MCALD score > 5.5 corresponded to an increased likelihood of cirrhosis (LR: 6.5, 95% CI: 4.3, 11.0) and a MCALD score < 5.5 corresponded to decreased likelihood of cirrhosis in alcoholics (LR: 0.25, 95% CI: 0.19, 0.36). Sobriety platelet count (after alcohol abstinence) at a cutoff of 160*10(3) had positive LR of 7.9 (95% CI: 4.4, 14) and negative LR of 0.42 (95% CI: 0.34, 0.52) for predicting cirrhosis in alcoholics.

CONCLUSIONS

A simple model of platelet count and INR has good diagnostic accuracy for identifying cirrhosis in alcoholics.