Assessment of Liver Fibrosis Grading with Non Invasive Scoring Systems Among Non Alcoholic Fatty Liver Disease (NAFLD) Patients

Background: The evaluation of degree of liver fibrosis is an important prognostic factor in the management of NAFLD patients. Noninvasive risk stratification is needed to triage individuals with advanced fibrosis for optimal treatment and surveillance. Objective: To find the frequency of fibrosis in NAFLD patients using multiple non-invasive tests and to match the performance of noninvasive tests in diagnosing liver fibrosis. Methods: An observational study done in Out-patient Clinics of National Institute of Liver and GI diseases (NILGID), Dow University Hospital from January 2021 to January 2022. All consecutive NAFLD patients during the study period were enrolled. Liver fibrosis was assessed in each patient with non invasive scoring including APRI score (AST to platelet ratio index), AST/ALT ratio, NFS (NAFLD fibrosis scores) and FIB-4. Results: 322 patients (mean age 44.84 ±10.94 years) were included. The mean values for ALT and AST levels were 40.67 ± 31.69IU/L and 31.85 ± 22.60 respectively. The best diagnostic accuracy was observed with FIB4 score having AUROC of 0.904. A robust correlation was observed between APRI index and FIB-4 score (r = 0.734, p-value < 0.01), and between FIB-4 score and NFS score (r = 0.700, p-value <0.01). Whereas correlation of APRI index with NFS score was moderate (r=0.394), and with AST/ALT ratio was weak (r = 0.201). Conclusion: Noninvasive markers, FIB4 and NFS score demonstrate a dependable ability to diagnose and rule out liver fibrosis, which proves to be an economical approach in management of patients with NAFLD


Introduction
N onalcoholic fatty liver disease (NAFLD) was first considered in the early 1980s as an unnamed condition that most closely resembled alcoholic hepatitis 1 and could cause cirrhosis.In the years since, NAFLD has been defined as one of the most pervasive causes of hepatic pathology, strongly associated with obesity and diabetes.While the most common presentation of this disease is patients presenting with simple steatosis, studies have shown that up to half of all patients with NAFLD will develop complications that may include liver fibrosis and cirrhosis, and may culminate in either hepatocellular carcinoma (HCC) or end stage liver failure.
Over the years following its discovery, the incidence of NAFLD has consistently increased.With the escalating rates of obesity, there are predictions that NAFLD might soon emerge as the primary cause of liver disease on a global scale.Based on current literature, it is estimated that around 37% of the universal adult population is 2 influenced by NAFLD.The distribution varies, with higher rates reported in the United States and Middle East as compared to Africa.In Western countries, the overall frequency of NAFLD varies from 15% to 40%, while in Asian countries, it ranges from 9% to 40%.As of 2020, the probable total prevalence of NAFLD in Asian countries is 29.6%, indicating that it may have NAFLD is often largely asymptomatic and often been described as an indolent disease.This in turn often leads patients to either miss the early signs or misperceive the danger of a condition that is closely linked to metabolic syndrome and type 2 diabetes mellitus.In addition, cardiovascular events have been identified as the most common cause of mortality in patients with NAFLD, 5 followed by cirrhosis and hepatocellular carcinoma.In light of such grave consequences, there is an onus on the medical community to correctly diagnose the presence of steatohepatitis and fibrosis in this population as the disease progression and prognosis depends largely on it.Incorrect perceptions about medical conditions may lead to detrimental decisions being taken by and for patients.
Assessment of liver fibrosis should be carried out among all patients with NAFLD which will predict the threat of upcoming development of hepatic complications and hence needed for management decisions, observing the disease progression and planning for surveillance strategies.
The noninvasive tests (NITs) are being established as cost controlled screening tools for risk stratification of patients for the development of advanced liver fibrosis.Scores like Fibrosis-4 Index (Fib-4), NAFLD Fibrosis Score (NFS), the ratio of the serum aspartate to alanine amino-transferase levels (AST/ALT), and aspartate aminotransferase to platelet ratio (APRI) have been deployed across various populations.NITs overwhelmed many restrictions of liver biopsies being performed and thus are now regularly integrated into expert medical 6 practice.
The sensitivity and specificity of these noninvasive markers has varied over different populations.Singh The suggested approach usually involves the sequential application of two NITs, first with the use of simple, inexpensive, serum-based tests which could be performed in the community (e.g., FIB-4 or NFS), which can be followed by a second set of measuresment of liver stiffness (LSM) by either a serum-based test (e.g., enhanced liver fibrosis test; ELF) or by transient elasto-

graphy (TE).
In a recent hospital based study, prevalence of NAFLD was estimated to be 75%, in a diabetic patient popula-10 tion in Northern Pakistan.Studies like these are few and far in between.Given the previously discussed disease severity we feel it is important to fill this gap in data for the population in Pakistan.Also owing to limited resources and lack of financial assistance, the patients in Pakistan, especially in rural areas do not have frequent hospital visits / medical checkups.
This study targets to evaluate the frequency of stage of liver fibrosis in NAFLD patients with several simple non-invasive scoring systems and to then compare the efficacy of various non-invasive biomarkers in the absence of a gold standard.So that timely intervention can be done in these underprivileged patients within limited resources.

Methods
It was an observational study in which 322 consecutive patients diagnosed with NAFLD on ultrasound, during the study period, and aged 18 to 65 years were recruited from the Out-patient Department (OPD) of National Institute of Liver and GI diseases (NILGID), Dow Unird versity Hospital from 4th January 2021 to 3 January 2022.Ethical approval was obtained from the Dow University Institutional Review Board (IRB 1842).Sample size was calculated using OpenEpi calculator with 95% confidence interval, 5% margin of error and 10 20% prevalence of stage 4 fatty liver patients .The calculated sample size was 246, which was raised up to 322 patients.
Laboratory and clinical data was collected during outpatient visits.Patients were omitted from the study in the presence of decompensated chronic liver disease, hepatoma/hepatocellular carcinoma, acute hepatic flare, acute on chronic liver failure or any other simultaneous liver disease or patients using alcohol or other hepatotoxic drugs.Pregnant or lactating females were also excluded from the study population as well as having systemic diseases like autoimmune diseases, tuberculosis and non hepatic malignancies.
Once written consent was obtained relevant clinical details including patient's demographics such as age, gender, marital status, height , weight and body mass index (BMI), comorbidities such as diabetes mellitus/ hypertension were gathered via structured interview based questionnaire.Laboratory investigations including serum albumin, liver function tests, fasting lipid profile and platelet count were also noted.
Cutoff values for APRI , was 0.5 for mild and 1.5 for advanced fibrosis respectively.
Whereas AST/ALT ratio>0.8 is taken an indicator of more severe liver disease.
Patients were consequently informed about their stage of liver fibrosis based on this scoring system and advised appropriate follow up visits accordingly.
The Statistical Package for the Social Sciences (SPSS) software, version 26 was used for data entry and analysis.Quantitative variables like clinical parameters and age were summarized using mean and standard deviation.Categorical variables such as gender and NAFLD severity were described using frequency and percentages.The normality of quantitative variables was evaluated using the Shapiro-Wilk test.Correlations between different indices were determined using Pearson's correlation coefficient.To assess the diagnostic performance of the indices for the severity of liver fibrosis, receiver operating characteristic (ROC) curves were generated.The area under the ROC curve (AUROC) and the optimal cut-off values were calculated for each non-invasive index.Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy (DA) were also calculated for these cut-off values.Statistical significance was considered if P values ≤ 0.05.The substantial result of the current study demonstrate that the FIB-4 score when compared with the APRI index, which is considered the most reliable in the absence 13 of liver biopsy , showed a significant correlation.Furthermore, a noteworthy correlation was observed between the NFS and the FIB-4 score.This finding implies that both tests can be utilized in a clinical setting to identify individuals with NAFLD who do not have advanced fibrosis.Using simple and non-invasive tests to rule out advanced fibrosis makes a diagnosis less costly and convenient for patients.With the current influx of NAFLD patients seeking evaluation at GI clinics, the utilization of these non-invasive tests has the potential to considerably decrease the need for other scans such as fibro scan.This would bring about substantial advantages for patients by focusing expensive tests on individuals with a higher likelihood of advanced liver disease, while also generating cost savings.In addition, all the previous studies cited also arrived at the conclusion that in contrast, the NFS only moderately correlated with the APRI index.In concurrence with those findings, our AUROC value for NFS score was 0.740.There is however some contradictory data available, which in its cohort of 78 young patients with biopsy proven NAFLD showed that when comparing the AUC for ROC curves, all scores including FIB-4 and NFS failed to predict any fibrosis, significant or otherwise.

patients
It should be noted however, that this study was contained to young adults, with a limited sample size.The authors have also suggested that stratifying score cutoffs on the basis of age ranges may help eliminate this discrepancy, as these scores have proven their usefulness when applied to middle aged adults such as those on McPherson or severe, when compared to studies done in Pakistan as well as those conducted across Europe and North
Using simple scoring systems, such as the one we utilized, offers a significant benefit because they can be easily derived from clinical and laboratory data.While it is true that calculating the scores may be complex, the individual indices can be effortlessly inputted into a calculator or spreadsheet with a pre-existing formula, making it accessible to all physicians.However, in our study, there is a drawback when considering the various scores or percentage values associated with moderate and severe fibrosis change.Ideally, all participants would have undergone a biopsy for a definitive diagnosis.Nevertheless, in our specific situation, this approach would have been expensive and burdensome for patients, potentially reducing the sample size and the reliability of our study.
The current study has few limitations of having a single center study and use of small sample size for analysis.Also the assessment of severity of liver fibrosis was done using various noninvasive markers and comparison of efficacy was done among each other without the use of gold standard liver histology or elastography.
This study recommends that the approach of employing simple and non-invasive tests can lead to a more costeffective and convenient approach to evaluate fibrosis among patients suffering from NAFLD.Given the increasing number of fatty liver disease patients, incorporating these tests into clinical practice could substantially reduce the need for more expensive procedures like fibro scan and elastography.Such a shift would prove especially beneficial in settings with limited resources, including countries like Pakistan, where a stronger healthcare framework and early detection are imperative.Moreover, this shift would empower doctors to initiate timely interventions.

Conclusion
This study establishes a strong robust correlation between the APRI index and the FIB-4 score, as well as between the FIB-4 score and the NFS score.These findings highlight the potential medical implication of both the NFS and the FIB-4 score in stratifying NAFLD population with advanced fibrosis which will effectively contribute in the proper management of these patients.

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already exceeded the figures seen in Western countries.One of the most recent NAFLD studies done in Pakistan gives a likely prevalence of 15% in the overall popu-4 lation.

FIB- 4
panel includes age, platelet count, AST, and ALT.Calculated from the following formula, Age ( in years) × AST level (in IU/L) 9 Platelet count ( × 10 /L) × √ALT ( in IU/L) Cut off values used were as follows: FIB-4 less than 1.45 as mild, 1.45 to 3.25 as moderate as and greater than 3.25 as severe fibrosis.

Table 1 )
diagnosed with NAFLD were enrolled and analyzed in this study having mean age of 44.84 ± 10.94 years, 91 (28.3%) were males and 231 (71.7%) were females.The mean platelet counts were 295.77 ± 90.85/uL, the mean ALT levels and the AST levels were 40.67 ± 31.69IU/L and 31.85 ± 22.60 respectively.(January -March 2024 | Volume 30 | Issue 01 | Page 39 CI confidence interval, DA diagnostic accuracy, PPV positive predictive value, NPV negative predictive value, AUC area under the curve

Table 4 :
Diagnostic performance of the indices for the risk of risk of severe liver fibrosis January -March 2024 | Volume 30 | Issue 01 | Page 40

Table 1 :
Clinical and demographic and features of study population (n=322)

Table 2 :
Severity of NAFLD with different indices

Table 3 :
Correlation coefficient between different indicespared to the APRI index, , with an AUC curve of 0.904 (95% CI 0.859-0.949).For this purpose, the ideal FIB-4 cutoff score was 1.190, with a sensitivity of 73.5%, specificity of 86.8%, and DA of 85.4%.Figure1displays the ROC curves of all indices for the identification of severe fibrosis.

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In a similar study conducted by McPherson et al. researchers found that the FIB-4 had the best AUC (0.86), implying that, based on their study's parameters, the FIB-4 exhibited the highest diagnostic accuracy, with the NFS ranking second in terms of diagnostic performance, with an AUC of 0.81.In our study the AUC for the FIB-4 test was 0.904, which is similar to McPherson.Similar conclusions were also obtained byDrolz et 174 respectively.
Ethical Approval: The Institutional Review Board, Dow University of Health Sciences, Karachi approved the study vide letter No.Ref: IRB-1842/DUHS/ Approval/ 2021 Conflict of Interest: The authors declare no conflict of interest.