Analysis of hepatic fibrosis risk factors using artificial neural networks
BOUHARATI KHAOULA
1,2*
,
BOUHARATI IMENE
3,4
, GUENIFI WAHIBA
5
,
GASMI ABDELKADER
5
, LAOUAMRI SLIMANE
5
1.Department of Epidemiology, Faculty of Medicine, Constantine University, ALGERIA
2.Laboratory of Health and Environment, UFAS Setif1 University, Setif, ALGERİA
3.Faculty of Medicine, Paris Sorbonne University, FRANCE
4.Laboratory of Intelligent Systems, UFAS Setif1 University, Setif, ALGERIA
5.Faculty of Medicine, Setif University Hospital, UFAS Setif1 University, Setif, ALGERİA
Abstract. Introduction: Following excessive scarring, an accumulation of connective tissue in
the liver causes fibrosis. This fibrosis is asymptomatic, but generates portal hypertension by
deviation in intra-hepatic blood flow. When this destroys the hepatic architecture by inducing a
dysfunction, it switches to cirrhosis. The factors involved are sometimes ill-defined. However,
the most common are hepatitis B and C and alcohol abuse. The analysis of these factors is very
complex. Methods: This study proposes an artificial intelligence tool, in particular artificial
neural networks in data analysis. We consider risk factors as input variables to the system. We
consider the risk of fibrosis as an output variable. Conclusion: When the learning of the
network is carried out from the proper cases followed at our hospital service of Setif in Algeria,
the transfer function created is adjusted to its minimum of errors. It then becomes possible to
assign random values to the input of the system to read the risk of fibrosis at the output.
Keywords: Liver fibrosis, Risk factors, Intelligent analysis, ANN
Received: June 12, 2021. Revised: April 13, 2022. Accepted: May 10, 2022. Published: July 1, 2022.
1. Introduction
Whatever the etiology, the sequela of liver
damage induces fibrosis. This is manifested
by scarring that replaces liver tissue with
collagen, which sometimes takes the form
of a dense network of fibers. At its
advanced stage, it transforms into nodular
cirrhosis, thus deforming the hepatic
vascular system [1], [2]. Often irreversible,
hepatic cirrhosis can lead to death.
They often relate known risk factors that
cause liver damage to gender, age, alcohol
abuse, diabetes and mainly viral load in
hepatitis B or C or [3 ].
We consider if obesity and type 2 diabetes
risk factors; it is because they make up a
metabolic co-morbidity associated with
non-alcoholic fatty liver disease (NAFLD).
This concerns the age group of 18 to 75
years [4]. Studies have also shown that
hyperlipidemia is also associated with
fibrosis [5-8]. The accumulation of fat in
the liver can determine the prevalence of
fibrosis [9]. The association of this disease
with coronary heart disease (CHD) is also
mentioned [10]. Given this complexity, a
classification of the severity of fibrosis is
established according to a score. A low
probability when the score is between 1 and
5. Medium probability is between -1.5 and
0.67 and High probability when this score
is greater than 0.67 [11].
The system is very complex to analyze by
classical techniques. This study proposes a
WSEAS TRANSACTIONS on BIOLOGY and BIOMEDICINE
DOI: 10.37394/23208.2022.19.17
Bouharati Imene, Boubendir Nasser-Dine,
Bouharati Khaoula, Laouamri Slimane
E-ISSN: 2224-2902
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technique based on the principles of
artificial intelligence, mainly the
application of artificial neural networks.
The constructed artificial neural network
has three layers (input layer, hidden layer,
and output layer). This is to make the
correspondence between the two spaces
(inputs-outputs). Risk factors are
considered as input variables to the system.
The risk of fibrosis is considered as an
output variable. From the values of the
proper cases followed at the level of our
university hospital of Seti in Algeria, the
learning of the network is carried out. Once
the network is optimized, it then becomes
possible to assign random values to the
input of the system to read the risk of
fibrosis at the output.
2. Material and method
Fibrosis is a multi-factorial disease. What
characterizes these factors is complexity
and uncertainty. The risk factors are
multiple. Some factors are known, some
other less so. Also, the weight of each
factor with precision is ignored. Besides the
factors mentioned above, other less frequent
factors also sometimes have their effect
such as drug effects, the genetic factor or
that linked to autoimmune diseases.
Analyzing those using classical
mathematical techniques is very difficult
and even impossible. This study addresses
the analysis of these risk factors by artificial
neural networks. This technique makes it
possible to deal with the complexity and
multitude of factors involved.
The factors analyzed in this study are
limited only to the three major factors,
which are hepatitis B and C and excessive
alcohol consumption.
Like natural neural networks, artificial
neural networks make the correspondence
between the two input-output spaces. The
initial data is stored, processed and returned
at the output [20]. The major advantage of
artificial neural networks is learning. By
introducing values at the input and the
result at the output, a transfer function is
created [21-23]. At each value entered, the
function is readjusted so that it remains
appropriate. This is done just by variations
of the mathematical coefficients called
weights. This continues until the function is
optimized to its minimum error. By this
ability to adapt to different complex
situations, neural networks apply in various
fields, especially the medical field [24];
[25].
The network applied to this analysis is a
multi-layer network (Figure 1). It took risk
factors for hepatic fibrosis as input
variables to the system. These factors
concern the patients followed at the
University Hospital of Setif in Algeria
(hepatitis B, hepatitis C and the age of the
patients). The alcohol abuse factor is not
supported because this factor did not arise
during our follow-up. The output variable
of the system expresses damage by fibrosis.
Mathematically, this function can be
represented by: df=fhb,hc,ap
Where : df: damage fibrosis
hb: hepatitis B
hc: hepatitis C
ap: age of the patient
2.1.Risk factors
Hepatitis B and C
Hepatitis B and C are contagious diseases
they contaminate whose transmission route
blood. These diseases are characterized by
inflammation of the liver. The infection
often remains mild. However, sometimes
(about 10%), it develops into a chronic
infection and can even develop into
cirrhosis or even liver cancer. WHO
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statistics, reports that the approximately
257 million infected cases are in a chronic
stage [12]. Viral hepatocyte infections
progress to acute hepatitis and even induce
hepatocellular carcinoma or ultimately
cirrhosis. Regardless of the existence of a
supposedly 95% effective vaccine,
hepatocellular carcinomas rank second
among fatal cancers [14].
Alcohol abuse
The severity and the risk of liver damage
is determined by the volume, frequency and
duration of alcohol consumption. While the
effect is often silent, signs may appear as
liver pain, accompanied by fatigue, fever,
jaundice and enlargement. The result is then
the risk of getting hepatitis, digestive
bleeding or even an imbalance of brain
function. If several risk factors are cited,
excessive alcohol consumption is an
aggravating factor for hepatitis C. Its effect
will be much more pronounced, especially
when it is combined with advanced age or
other factors such as obesity or
immunodeficiency [15-19].
Input Variables
Each variable is assigned numerically:
Hepatitis B: 1 (positive); 2 (negative)
Hepatitis C: 1 (positive); 2 (negative)
Age: 1 (adult); 2 (old)
Output variable
The degree of fibrosis damage expresses the
output variable of the system. This variable
is numerically coded in two states (1: low
impairment); (2: serious damage). When the
damage is considered serious, it can
degenerate into cirrhosis.
Model
The built system is multi-layered. An input
layer, a hidden layer and an output layer
(Figure 1). From the real values recorded, a
mapping between each input variable and
its corresponding output variable
The cases analyzed are 80 cases. Half is
taken for network learning. The adjustment
of the function is done after 100 iterations.
The variables specific to each newly
introduced patient are combined with the
function. The other half is used for testing
the function created.
After optimizing the function to its
minimum error (Figure 2), the system
created makes it possible to introduce
random values at the input to read the result
at the output (Figure 3). The result obtained
at the output is the aggregation of all the
inputs. In this way, it will be as precise as
possible.
Fig. 1. System Architecture
Fig. 2. Function optimisation
3. Results and discussion:
The risk factors that necessitate this
infection are multiple. Also, the effect of
each factor is often poorly understood with
their classic physiological specificity
interaction [20].
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For this reason, classical mathematical
methods are unsuitable for analyzing this
kind of situation. Often, it is a matter of
applying statistical methods. These methods
arrive at imprecise results and remain in the
realm of the probable. The proposed
technique applies a domain of artificial
neural networks. These networks have the
ability to take on a large number of
variables and combine them [21-23].
The result is the aggregation of all input
variables. As these networks have the
ability to learn, it is simply a matter of
introducing real variables at the input while
assigning the result to it at the output. A
transfer function that links the inputs to the
output is created. With each new case, the
function is adjusted. In the case of the
study, three input variables are taken into
consideration (hepatitis B, C and the age of
the patients). In each case, a
correspondence between these variables and
the degree of attack by hepatic fibrosis is
done. After learning, the result will be as
accurate as possible in terms of reading this
degree later. It should be noted that the
network remains extensible to other factors
that are not taken into account in this study.
Fig. 3. Degree of fibrosis damage variations
4. Conclusion:
In order to implement a screening and
follow-up program at the scale of a
population with hepatitis B or C, this tool
provides an idea of the evolution of
fibrosis. From the rate of progression of
hepatitis in people according to their age,
the identification of fibrosis and even its
possible evolution into cirrhosis becomes
possible. The system establishes a
correspondence function between the risk
factors as input variables and the state of
fibrosis as the output variable. From the
real cases used in learning the network, its
application becomes valid later for new
cases that arise. As such, it can be
considered as a preventive tool. This makes
it possible to predict the impact of each
input parameter on the progression of the
risk of fibrosis.
In future studies and with the enrichment of
the data including other variables that are
not considered in this study, the precision
will be increased.
Financial support and sponsorship:
Nil.
Conflicts of interest:
There are no conflicts of interest.
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DOI: 10.37394/23208.2022.19.17
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