Study to Determine the Hepatitis C Virus Infection Prevalence Among Patients Attended Primarily for Vasculitis
Study to Determine the Hepatitis C Virus Infection Prevalence Among Patients Attended Primarily for Vasculitis
Chronic hepatitis C infection (CHC) is usually asymptomatic; nevertheless, there are studies
 that show that up to two thirds of patients may present some type of extrahepatic
 manifestation. The most frequent extrahepatic manifestation is type II mixed cryoglobulinemia
 (MCG-II) and clinically the most common presentation is leukocytoclastic vasculitis (LCV)
 with palpable purpura that affects the lower extremities. It is estimated that up to 80% of
 MCG-II cases are due to CHC. Also, previous studies have demonstrated that CHC prevalence is
 higher in patients with autoimmune diseases compared with general population. Therefore, if
 vasculitis is an extrahepatic manifestation of CHC, then the prevalence of CHC infection in
 this group of patients could be higher than the prevalence reported in general population.

 The aim of the study is to know the prevalence of CHC, determined by serological rapid test
 for hepatitis C screening, then all positive cases will be confirmed by quantitative viral
 load, in patients who consult primarily to a rheumatology department for "vasculitis" or
 other potential hepatitis C extrahepatic manifestations (rheumatological conditions).
1. Introduction.

 The prevalence of Hepatitis C determined by serological test to detect antibodies
 against the hepatitis C virus (HCV) is around 1.4% in Mexico, being slightly higher in
 the north (2.0%) than in the south (1.5%). ) and the entities of the center (1.1%) of
 the country. However, there are high risk groups where the prevalence is much higher,
 for example, among intravenous drug users such as heroin, it is estimated that
 prevalence of hepatitis C is as high as 11.7%, with an interval ranging from 2.7 to
 39.1% .

 Recently, the Global Prevalence study of HCV - Polaris Observatory at American
 Association for de the Study of Liver (AASLD), has documented that the prevalence in
 Mexico determined by viral load quantification (which is the most specific study) ranges
 from 0.0 to 0.6%, being higher in the North, than in the Center and in the South of the
 country.

 Although it is classically considered that chronic hepatitis C infection (CHC) is
 usually asymptomatic, there are studies that show that up to two thirds of patients may
 present some type of extrahepatic manifestation. The most frequent extrahepatic
 manifestation is type II mixed cryoglobulinemia (MCG-II) and clinically the most common
 presentation is leukocytoclastic vasculitis (LCV) with palpable purpura that affects the
 lower extremities. It is estimated that up to 80% of MCG-II cases are due to CHC. The
 prevalence of CHC infection has been reported in higher numbers in patients with LCV
 than in the general population. A multinational study in 2009, found that the prevalence
 of anti-HCV antibodies specifically in patients consulting for "autoimmune diseases" was
 as high as 8.7%, compared to healthy subjects (general population) where it was 0.4%. In
 this study, the diagnosis of CHC with determination of viral load or genotype was not
 confirmed.

 In another study, conducted in Brazil, which included 367 patients with rheumatological
 diseases, the prevalence of CHC, confirmed with viral load determination, was 1.9%, also
 higher than that reported in the open population in that country. The difference
 remarkable in the prevalences reported by serological tests and by viral load,
 particularly in patients with autoimmune diseases, can be explained because patients
 with autoimmune diseases have autoantibodies that can generate cross reactions and
 result in false positives, for this reason, in the presence of a positive result in
 these tests, must always be confirmed with the gold standard that is the quantification
 of viral load.

 2. Research question.

 Will the prevalence of hepatitis C determined by quantitative viral load be higher in
 patients who consult as first-line for vasculitis, a possible extrahepatic manifestation
 of HCV, compared to that reported in the general Mexican population?

 3. Approach of the problem.

 Previous studies in other countries show that the prevalence of HCV infection is higher
 in patients with autoimmune clinical manifestations, specifically vasculitis, since this
 may be extrahepatic manifestation of HCV, compared to the general population.

 In Mexico, the prevalence of HCV in the population of patients with "vasculitis" has
 never been evaluated.

 Since the timely detection of chronic HCV infection requires a high degree of suspicion
 based on the patient's risk factors, and since their symptoms are totally nonspecific,
 and knowing that vasculitis associated with MCG-II is the most extrahepatic
 manifestation common of HCV, the investigators consider relevant to perform an HCV
 screening in this group of patients.

 4. Justification.

 At present, HCV infection is curable with high effectiveness, achieving the sustained
 viral response in more than 95% of cases with the new direct antiviral agents. Early
 diagnosis depends on the patient having access to an effective treatment and that
 achieving a virological cure achieves a favorable prognosis for function and life.

 5. Hypothesis.

 If vasculitis is an extrahepatic manifestation of HCV, then the prevalence of chronic
 HCV infection in this group of patients will be higher than the prevalence reported in
 the general population.

 6. Objectives.

 General: To know the real prevalence of hepatitis C determined by quantitative viral
 load in patients who consult for the first intention to a rheumatology department for
 "vasculitis and with a positive result in the serological HCV screening test".

 Specific(1): To describe the clinical characteristics of hepatic and extrahepatic
 manifestations of patients with "vasculitis" detected with Hepatitis C.

 Specific (2): To determine the real prevalence of hepatitis C determined by quantitative
 viral load in patients who consult for other rheumatological conditions (non-vasculitis)
 with a positive result in the serological HCV screening test.

 7. Material and methods.

 1. Type and design of the study: Observational study, case series, descriptive and
 analytical.

 2. Inclusion criteria: Patients who first attend to a Rheumatology department, to be
 evaluated for diagnosis of "vasculitis under study" or "vasculitis of origin to be
 determined" or "rheumatological condition for study".

 3. Exclusion criteria: Patients who do not wish to participate in the study.

 4. Elimination criteria: Patients who do not have a complete clinical file.

 5. Population and sample size:

 Population: All patients who first attend to a Rheumatology department, to be
 evaluated for diagnosis of "vasculitis under study" or "vasculitis of origin to be
 determined" or "rheumatological condition for study".

 Sample size: Assuming a prevalence of between 5 to 10%, in this specific
 population, a total of 1000 patients need to be evaluated, to find between 50 to
 100 patients with chronic HCV infection.

 6. Data collection and Procedures: The investigators will obtain the informed consent
 from patients; demographic, clinical, biochemical data of the clinical file will be
 collected. A quick test will be taken in the office for HCV detection, if it is
 negative, it is recorded in the data collection form and the patient will be
 discharged from this clinical study to continue the usual care in Rheumatology. If
 this test is positive, the patient will be given a request for viral load and
 genotype and an appointment will be made for follow-up of the case in the Liver
 Clinic.

 8. Relevance and expectations

 This will be the first study in Mexico to characterize a population that suffers from
 vasculitis, the most common extrahepatic manifestation related to MCG-II in patients with
 HCV, and other rheumatological conditions, as potential extrahepatic manifestations of CHC.

 This study will allow to know the prevalence in this special group of patients, in addition
 to the research purposes that fall within this prevalence study, patients will have access to
 a detection and treatment program in a timely manner.
Inclusion Criteria:

 -  patients who primarily consults to a rheumatology department for vasculitis and agree
 to be evaluated through a questionaire to identify risk factors for hepatitis C and
 who also agree to be screened with a serological rapid test for hepatitis C.

 Exclusion Criteria:

 -  patients who decline to participate