Albumin-bilirubin score in non-malignant liver and other diseases

Abstract

The albumin-bilirubin (ALBI) score is derived from albumin and bilirubin levels. Currently, the ALBI score is widely used in various clinical settings. A recent article in the World Journal of Gastroenterology summarized the application of the ALBI score in various non-malignant liver diseases. The ALBI score has a predictive power that is superior or non-inferior to established numerous measures. This may be related to its contiguity, sensitivity, and inclusion of albumin. While we recognize the good results of the ALBI score in a number of diseases, the ALBI score also has limitations. Variation studies for population characteristics and other factors should be performed to validate the performance of ALBI. Further modifications or optimization of ALBI scores should be taken into account.

Key Words: Albumin-bilirubin score; Liver cirrhosis; Hepatitis; Liver transplantation; Liver injury

Core Tip: A recent article in the World Journal of Gastroenterology reviewed the application of the albumin-bilirubin (ALBI) score in various liver diseases. The ALBI score shows predictive power comparable to established measures, possibly due to its continuity, sensitivity, and inclusion of albumin. However, despite promising results, the ALBI score has limitations. We believe population-specific validation studies and consideration of modifying factors are essential to ensure its accuracy and reliability in diverse patient populations.

TO THE EDITOR

The albumin-bilirubin (ALBI) score is a measure of liver function that is calculated using albumin and bilirubin levels. The formula for calculating the ALBI score is: ALBI score = 0.66 × log10 (total bilirubin in μmol) - 0.085 × (albumin in g/L)[1]. The score is stratified into three grades: (1) Grade I (≤ -2.60); (2) Grade II (> -2.60, but ≤ -1.39); and (3) Grade III (> -1.39). A high ALBI score indicates impaired liver function due to elevated bilirubin and reduced albumin levels.

ALBI SCORE

The ALBI score was first used to evaluate liver function in patients with hepatocellular carcinoma and has since been extended to assess non-malignant liver diseases[2]. In the current issue of the World Journal of Gastroenterology, Xu et al[3] reviewed the role of the ALBI score in primary biliary cholangitis, hepatitis, cirrhosis, and liver transplantation. ALBI is an outperformed prognostic factor for progression, liver failure, mortality, and liver transplantation compared to Child-Pugh, model for end-stage liver disease (MELD), Mayo risk, etc. Furthermore, previous studies have proposed its potential applications in areas such as malnutrition[4] and treatment response[5].

The ALBI score has demonstrated superiority or non-inferiority to established measures such as Child-Pugh[6] and the MELD[7] in predicting outcomes such as prognosis[8] and mortality[9]. Due to its continuous calculation, the ALBI score allows for nuanced assessment without the use of discrete cutoff values (Table 1). In addition, its continuous calculation improves its sensitivity to small changes in bilirubin and albumin levels, making it a superior model compared to discrete score, such as Child-Pugh. The inclusion of albumin, a less commonly used parameter compared to bilirubin, contributes to its superior performance. In addition, fewer included factors and objective factors such as hepatic encephalopathy also make ALBI convenient and robust.

Table 1 Comparison of Child-Pugh, model for end-stage liver disease, and albumin-bilirubin.

Parameter	Child-Pugh	Model for end-stage liver disease	Albumin-bilirubin
Included factors	Bilirubin, albumin, hepatic encephalopathy, ascites, prothrombin time	Creatinine, bilirubin, hemodialysis, international normalized ratio	Bilirubin, albumin
Calculation	Grading score, discontinuous	Formula, continuous	Formula, continuous
Application	Liver cirrhosis	End-stage liver disease	Liver disease

However, the ALBI score has limitations. Inconsistent performance across studies may result from variability in population characteristics and other factors, requiring rigorous validation through large-scale trials[10]. In addition, it does not comprehensively encompass all diseases or outcomes, requiring careful consideration and potential modifications for specific conditions. Furthermore, the ability of the ALBI score to generalize in a simple computational way presents a dilemma when combined with other factors[10]. Combinations with other factors may improve performance on specific diseases, but this may reduce its ability to generalize. In addition, some studies have reported the prognostic ability of ALBI on heart failure[11], non-small cell lung cancer[12], nervous system tumors[13], etc. A simple formula leads to greater generalization and lower specificity. Any modifications should be carefully considered and extensively validated. Furthermore, many diseases besides liver disease can cause changes in albumin and bilirubin. The potential application of ALBI on other diseases is worthy of further research.

CONCLUSION

Despite these challenges, we believe that the ALBI score has potential as an indicator and will be used in more diseases or outcomes. Further research will validate its performance and expand or clarify its indications.