Platelet count/spleen diameter ratio: proposal and validation of a non-invasive parameter to predict the presence of oesophageal varices in patients with liver cirrhosis

Abstract

Background and aims: Cirrhotic patients frequently undergo screening endoscopy for the presence of oesophageal varices (OV). In the future, this social and medical burden will increase due to the greater number of patients with chronic liver disease and their improved survival. In this study, our aims were (1) to identify clinical, biochemical, and ultrasonographic parameters which might non-invasively predict the presence of OV in patients with liver cirrhosis; (2) to evaluate the reproducibility of the obtained results in a different, although related, further group of patients; and (3) to assess the predictiveness of the identified rules in patients with compensated cirrhosis.

Methods: In the first part of the study we retrospectively evaluated the presence of OV in 145 cirrhotic patients, and in the second part we evaluated the reproducibility of the study results in a subsequent group of 121 patients. Finally, we evaluated these parameters in a subgroup of 145 patients with compensated disease. All 266 patients underwent a complete biochemical workup, upper digestive endoscopy, and ultrasonographic measurement of spleen bipolar diameter. Platelet count/spleen diameter ratio was calculated for all patients.

Results: The prevalence rates of OV were 61% and 58% in the first and second groups of patients, respectively. In the first part of the study, we found that platelet count, spleen diameter, platelet count/spleen diameter ratio, and Child- Pugh class were significantly different among patients with or without OV, although the platelet count/spleen diameter ratio was the only parameter which was independently associated with the presence of OV in a multivariate analysis. A platelet count/spleen diameter ratio cut off value of 909 had 100% negative predictive value for a diagnosis of OV. This result was reproduced in the second group of patients as well as in patients with compensated disease. In a cost-benefit analysis, screening cirrhotic patients according to the "platelet count/spleen diameter ratio strategy" was far more cost effective compared with the "scope all strategy".

Conclusions: The platelet count/spleen diameter ratio is the only parameter which is independently associated with the presence of OV, and its negative predictive value is reproducible. Its use is of value even in the subgroup of patients with compensated disease, and it is also cost effective.

Figure 1

Receiver operating characteristic curve showing the platelet count/spleen diameter ratio cut off with the best sensitivity and specificity on the basis of the presence of any oesophageal varices.

Figure 2

Dot diagram showing patient distribution on the basis of the presence/absence of oesophageal varices (OV) and a platelet count/spleen diameter ratio cut off of 909 in 145 patients with compensated cirrhosis. NOV, no oesophageal varices.

Figure 3

Flow chart showing cost-benefit analysis of the “scope all strategy” compared with the “platelet count/spleen diameter ratio strategy”. A unitary cost of 150 Euros for each diagnostic upper digestive endoscopy is applied, with no extra costs for abdominal ultrasonography. The prevalence of oesophageal varices in the study population is 60%. OV, oesophageal varices; NOV, no oesophageal varices.