Letter to the Editor: Enhancing fibrosis prediction in metabolic dysfunction-associated steatotic liver disease: The potential of combined biomarker approaches

Abstract

This letter discusses a study by Duarte et al, published in the World Journal of Hepatology. evaluating routine inflammatory markers for predicting liver fibrosis in metabolic dysfunction-associated steatotic liver disease. While parameters like neutrophil-to-lymphocyte ratio, systemic inflammation response index, and C-reactive protein showed significant associations with fibrosis, their individual diagnostic accuracy remained limited (area under the receiver operating characteristic curve < 0.7), highlighting the inadequacy of systemic inflammatory surrogates for organ-specific pathology. We argue for a shift toward integrative diagnostics, proposing a mechanism-informed strategy that combines accessible systemic markers (e.g., high-sensitivity-C-reactive protein) with novel hepatic biomarkers (e.g., N-terminal propeptide of type III collagen, liver-enriched microRNAs, fatty acid-binding protein 4). This approach enables multidimensional assessment, balancing accessibility with improved specificity and dynamic monitoring potential. Future priorities include validating combined panels against clinical outcomes, establishing actionable thresholds, and developing personalized algorithms. Integrating biomarkers across biological domains promises to advance metabolic dysfunction-associated steatotic liver disease management toward precision risk stratification and dynamic monitoring, improving patient prognosis.

Key Words: Metabolic dysfunction-associated steatotic liver disease; Liver fibrosis; Biomarkers; Diagnostic strategy; Inflammatory indices

Core Tip: This letter highlights the limited diagnostic accuracy of conventional markers (e.g., neutrophil-to-lymphocyte ratio and C-reactive protein) for predicting liver fibrosis in metabolic dysfunction-associated steatotic liver disease. To advance precision management, we propose a shift toward an integrated diagnostic paradigm. This strategy combines accessible systemic inflammation indices with novel biomarkers reflecting specific hepatic processes, such as N-terminal propeptide of type III collagen for fibrogenesis, liver-specific microRNAs, and metabolic proteins, such as fatty acid-binding protein 4. Future research should prioritize validating such mechanism-informed combinations to enable multidimensional risk assessment, establish actionable clinical thresholds, and guide personalized monitoring and intervention, ultimately improving prognosis in this heterogeneous patient population.

TO THE EDITOR

We read with great interest the recent study by Duarte et al[1], published in the World Journal of Hepatology. The authors systematically evaluated conventional inflammatory indices, including the neutrophil-to-lymphocyte ratio (NLR), systemic inflammation response index, aggregate index of systemic inflammation, prognostic nutritional index, and C-reactive protein (CRP) level, using data from the National Health and Nutrition Examination Survey to assess their predictive value for liver fibrosis in patients with metabolic dysfunction-associated steatotic liver disease (MASLD)[1]. Although these accessible parameters showed statistically significant associations with fibrosis, their individual predictive accuracy was limited, with the area under the receiver operating characteristic curve values below the clinically useful threshold of 0.7, rendering them inadequate as standalone diagnostic tools. This finding reinforces a central principle in hepatological biomarker research: A statistical association does not equate to the clinical utility of individualized patient management.

The authors’ work provides important clarification, shifting their attention away from the pursuit of a single optimal biomarker to understanding the complementary roles that different classes of biomarkers may play in the evaluation of complex diseases. Although Duarte et al[1] clearly delineated the performance limitations of common hematological inflammatory indices, their analysis also appropriately prompted a deeper consideration of future directions for non-invasive liver fibrosis assessment. We believe that the logical next step, guided by evidence, is not to discard these highly accessible markers, but to explore how they can be strategically combined with emerging mechanistically specific biomarkers to construct a multidimensional and precise diagnostic and risk stratification system[2]. Such an integrative strategy could address a critical gap in current clinical practice, enabling more accurate risk stratification in a highly heterogeneous MASLD population, while preserving the feasibility of widespread screening[3].

INHERENT LIMITATIONS OF CONVENTIONAL INFLAMMATORY INDICES AND THE PATHOPHYSIOLOGICAL VALUE OF NOVEL BIOMARKERS

The findings of Duarte et al[1] are well supported. Indices such as NLR and systemic inflammation response index, derived from peripheral blood cell counts, reflect systemic, non-organ-specific inflammatory responses. In contrast, MASLD-associated fibrosis results from organ-specific hepatic processes, including lipotoxicity, oxidative stress-mediated hepatocyte injury, activation of resident immune cells, and dysregulated extracellular matrix turnover[3]. Although systemic inflammation mirrors these events, it is a downstream and non-specific consequence. Therefore, to improve diagnostic accuracy, it is necessary to look beyond these systemic surrogate markers and identify biomarkers that more directly and specifically reflect key intrahepatic pathological events.

Markers of extracellular matrix turnover

These markers directly quantify fibrogenesis and matrix degradation. The enhanced liver fibrosis test, which incorporates hyaluronic acid, a tissue inhibitor of metalloproteinase-1, and the N-terminal propeptide of type III procollagen, is a well-validated example[4]. N-terminal propeptide of type III collagen (PRO-C3), a neoepitope-specific marker of type III collagen formation, is particularly noteworthy. Multiple studies have confirmed that PRO-C3 correlates more closely with histological fibrosis stage and activity in MASLD than traditional indices, more sensitively reflects active intrahepatic fibrogenesis, and may offer unique value for monitoring treatment responses[5].

Markers of hepatocyte injury and death

Hepatocyte damage initiates an inflammatory cascade that activates hepatic stellate cells. Cytokeratin-18 fragments, specifically M30 (apoptosis-related) and M65 (total cell death-related) epitopes, are released into circulation upon hepatocyte injury[6]. These markers are primarily used to distinguish simple steatosis from steatohepatitis, and their levels correlate with the severity of fibrosis, thus providing supplementary information on disease activity.

Proteins related to metabolic dysregulation and lipotoxicity

Given that metabolic dysregulation is the core driver of MASLD, the identification of related markers is essential. For instance, fatty acid-binding protein 4 (FABP4), an adipokine, and lipocalin-2, a protein involved in inflammation and metabolic regulation, are elevated in patients with MASLD and correlate with disease severity[7,8]. These markers capture aspects of metabolic dysfunction, a dimension that is not reflected by conventional inflammatory indices.

Organ-enriched circulating nucleic acid markers

Liver-enriched microRNAs (miRNAs), such as miR-122 (the most abundant miRNA in hepatocytes) and miR-34a (upregulated in MASLD and linked to metabolic pathways), are stable in the blood, and changes in their expression correlate with the fibrosis stage[9]. Tissue specificity offers several advantages over the use of systemic markers.

Integrated multi-omics-derived signatures

Advances in high-throughput technologies, including proteomics and metabolomics, have enabled the identification of composite biomarker signatures in large datasets. These signatures can simultaneously reflect disturbances in multiple pathways, such as inflammation, fibrosis, and metabolism, thereby providing a more comprehensive biological profile of the disease[10].

Notably, the combination of these markers with systemic inflammatory indices is not arbitrary. Mechanistically, indicators such as FABP4 can reflect adipose tissue dysfunction, which drives metabolic stress and lipotoxicity, leading to hepatocyte damage and the release of markers such as miR-122. This, in turn, activates local and systemic inflammation, resulting in elevated levels of hs-CRP, NLR, and other factors, ultimately promoting hepatic stellate cell activation and extracellular matrix deposition, and increasing PRO-C3[5,8,9]. Therefore, the simultaneous evaluation of markers at different stages of this cascade provides integrated information on disease-driving factors (metabolism), active injury, inflammation, and the terminal effects of fibrosis. The diagnostic and prognostic value of this approach is theoretically additive or synergistic.

TOWARD AN INTEGRATIVE APPROACH: FROM SEQUENTIAL TRIAGE TO MECHANISM-INFORMED COMBINATION STRATEGIES

A major implication of the study by Duarte et al[1] is the need to transition from a paradigm focused on selecting individual biomarkers to one that emphasizes their combined use based on complementary mechanisms. We propose the following strategic framework for integration.

Sequential/triage model-optimizing resource allocation

This clinically and economically efficient method is suitable for primary care and large-scale screening. Initial risk assessment uses low-cost, widely accessible tools, such as the fibrosis-4 index or basic models incorporating simple inflammatory indices (e.g., high-sensitivity CRP and NLR)[4]. Individuals classified as having intermediate or indeterminate risk are then referred for secondary testing with more specific and potentially high-cost markers (e.g., the enhanced liver fibrosis test, PRO-C3, or targeted miRNA profiles) for refined risk stratification[11]. This stepped approach directs advanced diagnostic resources to those most likely to benefit, thereby optimizing the overall healthcare efficiency.

Mechanism-informed combined testing-enabling multidimensional assessment

This strategy emphasizes flexible clinical decision-making guided by pathophysiology. Its core principle is the concurrent interpretation of conventional and accessible indicators of systemic inflammatory status (e.g., high-sensitivity CRP and NLR), along with novel biomarkers that reflect liver-specific pathological processes (e.g., PRO-C3 and specific miRNAs)[12]. For example, when managing patients with MASLD and type 2 diabetes, clinicians may concurrently measure high-sensitivity CRP to assess the systemic inflammatory burden, PRO-C3 to evaluate ongoing hepatic fibrogenic activity, and FABP4 to gauge the severity of adipose tissue dysfunction and metabolic dysregulation. This combination yields a multidimensional pathophysiological profile: (1) A significantly elevated high-sensitivity CRP may indicate a need for systemic anti-inflammatory management; (2) A high PRO-C3 level signals active fibrogenesis, possibly warranting consideration of anti-fibrotic therapy or intensified monitoring; and (3) FABP4 levels can indicate the risk of metabolic complications and guide lifestyle or pharmacological intervention[13,14]. However, the main challenge of this strategy lies in the coordination and standardization of clinical workflows, rather than technical incompatibility. Future prospective studies should focus on validating the feasibility of this strategy in real-world settings.

FUTURE PERSPECTIVES: CHALLENGES AND KEY RESEARCH DIRECTIONS

Developing and validating the proposed integrative strategies is promising but faces practical challenges, including standardization of novel biomarker assays, cost-effectiveness, prospective validation in large and diverse cohorts, and demonstrating improved net clinical benefits compared to existing standards (e.g., fibrosis-4, liver elastography). Therefore, we recommend that future research should focus on the following key areas.

Prospective validation of mechanism-informed strategies

Pragmatic clinical trials should assess whether adding a novel, mechanism-specific biomarker (e.g., PRO-C3) to conventional clinical scores for combined decision-making improves the diagnostic accuracy for advanced fibrosis, reduces unnecessary liver elastography or biopsy, and optimizes patient management pathways[2].

Definition of clinically actionable decision thresholds

Studies should establish specific, clinically applicable cutoff values for biomarkers within combined testing approaches, including dual-threshold strategies, to reliably rule out and rule in disease states[9]. Additionally, the relative weights of different biomarkers reflecting the same mechanism should be determined based on multivariate statistical models alongside a hypothesis-driven framework based on pathophysiological significance. Ultimately, the weights should be determined by integrating both approaches and validating them in independent cohorts.

Exploration of tailored strategies for heterogeneous populations

Given the significant ethnic, genetic, and metabolic heterogeneity in MASLD, future studies should evaluate the performance of integrated models in different subgroups (e.g., carriers of the patatin-like phospholipase domain-containing 3 risk allele and patients across body mass index categories) and consider developing subgroup-specific algorithms[15].

Longitudinal monitoring and treatment response prediction

The clinical value of a combined biomarker test is not only for cross-sectional risk stratification but also for predicting the dynamic progression of the disease. For example, a decline in PRO-C3 levels may precede observable fibrosis regression on imaging or histology, whereas miR-122 levels may normalize more rapidly as hepatic steatosis or inflammation improves[11,16]. This sequential, multi-pathway response pattern helps distinguish between mere improvement in inflammatory markers and genuine induction of anti-fibrotic effects, thereby providing a basis for adjusting treatment strategies. However, this finding requires further validation in future cohort studies.

CONCLUSION

We acknowledge the valuable work of Duarte et al[1]. Their research provided a clear and rigorous demonstration of the limitations of conventional inflammatory indices in the independent diagnosis of liver fibrosis. This study should serve as a catalyst for encouraging the field of hepatology to move beyond evaluating single biomarkers in isolation to a new phase, focusing on the integrated use of multidimensional biomarker information. Through a judicious combination of the systemic perspective offered by conventional indices and the mechanistic specificity of novel biomarkers, next-generation liver fibrosis risk assessment tools can be developed. Such tools represent not only diagnostic advances but also critical steps toward precision medicine in MASLD, ultimately improving long-term outcomes for patients worldwide.

ACKNOWLEDGEMENTS

We are sincerely grateful to Dr. Guo-Yuan Li from the Women and Children’s Medical Center Affiliated to Guangzhou Medical University for his support of this research.