Prevalence of hepatitis C in patients with renal disease undergoing hemodialysis treatment

First submission on 03/01/14; last submission on 15/08/14; accepted for publication on 07/09/14; published on 20/10/14 1. Biomedical scientist. 2. Master’s degree in Medicine and Health Sciences from Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS); nurse at Hospital Nossa Senhora da Conceição, Porto Alegre-RS. 3. PhD in Genetics and Molecular Biology from Universidade Federal do Rio Grande do Sul (UFRGS); professor at Universidade Feevale, Novo Hamburgo-RS, and Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA). ABStrACt


introDuCtion
Renal disease is defined by damaged or decreased kidney function.Renal damage can result from any disease potentially able to reduce the functional capacity of the kidneys.It is a multifactorial disease that represents a serious public health problem due to the increasing percentage of patients who become chronically ill, and to the numerous comorbidities that often accompany it.There are several treatment forms, including hemodialysis.The disease can be controlled for some time, but it is progressive, incurable and has high morbidity and mortality rates (1,12) .Hepatitis C is a liver disease, caused by hepatitis C virus (HCV), a ribonucleic acid (RNA) virus of the Flaviviridae family, whose replication process takes place in the hepatocyte cytoplasm.The clinical manifestations of hepatitis C are classified as acute and chronic.The acute infection is usually asymptomatic, but has a high chronicity rate that may reach 80% of the cases (15) .Renal patients that undergo hemodialysis are particularly prone to contamination by HCV due to the several risk factors they are exposed to.Among these factors, we may draw attention to treatment duration, blood transfusions and the virus prevalence in the hemodialysis unit (12,13) .
According to Boletim Epidemiológico de Hepatites Virais de 2012, from 1999 to 2011, in the South region, 18,307 confirmed cases of hepatitis C were reported to the Notifiable Diseases Information System (SINAN).This represents 22.3% of the notified cases in Brazil.Most of them were in the state of Rio Grande do Sul (58.2%), followed by Santa Catarina (25.6%) and Paraná (16.2%) (3) .
Concerning renal disease, the estimated number of patients undergoing dialysis in Brazil in 2011 was 91,314.Prevalence estimates for 2011 were 475 dialysis patients per million of the population.Among them, 90.6% were on hemodialysis, and 31.5% were 65 years or older.For 2011, the estimated number of patients beginning dialysis was 28,680, and the annual mortality rate was 19.9% (17) .
10.5935/1676-2444.20140035oBJECtivE Based on the relevance of the subject, this work aimed at determining the prevalence of hepatitis C in patients diagnosed with acute or chronic renal disease.All of them underwent hemodialysis at a hemodialysis unit in a large hospital in Porto Alegre-RS, from January to December, 2012.This paper also aimed at relating the gathered data to the national census mass of data, reporting cases of patients coinfected with hepatitis C and the human immunodeficiency virus (HIV), and finally, defining the demographic profile of the patients.

MEthoD
A cross-sectioned observational study, with a descriptive analytical approach, was carried out for the determination of hepatitis C prevalence in 649 patients diagnosed with acute or chronic renal disease undergoing hemodialysis from January to December 2012.The used data base obtained information from the electronic records of patients.
The survey was conducted at a hemodialysis center of a large hospital in Porto Alegre-RS.That unit serves exclusively their inpatients from the Unified Health System (SUS) who began the hemodialysis treatment due to diagnoses of renal failure.It also serves inpatients with other diseases who present with renal failure, coming from other hemodialysis clinics of the metropolitan region or the inner state.The center also provides treatment for a group of patients with chronic renal failure who are regularly served at a hemodialysis program in the institution.
The sample was composed of 649 patients with acute or chronic renal failure, undergoing hemodialysis from January to December 2012 in the surveyed institution.This work was submitted to and approved by the Ethics Committee of Universidade Feevale, according to report nº 245.621.It was also assessed by the Ethics Committee of Grupo Hospitalar Conceição, being approved according to report no.308.906.
In order to access the data bank of the surveyed institution, a data use agreement was signed.

rESuLtS
The results presented in Table 1 refer to a sample of 649 investigated patients receiving hemodialysis from January to December 2012.The results from Table 2 refer to the 66 patients diagnosed as being anti-HCV positive.
Finally, the results from Table 3 refer to the 12 patients coinfected with HCV and HIV.
The Ministry of Health, at Boletim Epidemiológico de Hepatites Virais de 2012, reveals an index of 1.38% of prevalence of hepatitis C for the general population.According to the same study, 82,041 cases of hepatitis C were confirmed in Brazil from 1999 to 2011, with 22.3% only in the South region.Among these 22.3% national cases, 58.2% occurred in Rio Grande do Sul (RS).Among the capitals of the South region, in 2010, the highest case detection rate per 100,000 inhabitants was observed in Porto Alegre-RS: 40.4% (3) .
Prevalence of hepatitis C in patients with renal disease undergoing hemodialysis treatment According to the Brazilian Society of Nephrology (SBN), the prevalence rates of hepatitis C in dialysis centers in the whole Brazil was 19.9% in 2000, and 9.1% in 2007, showing a 50% reduction in less than 10 years (18) .

DiSCuSSion
The prevalence of hepatitis C observed in the present study (10.17%) may be considered low when compared to the survey by Gomes et al. (2006), which reported 29.1% of HCV infection in dialysis patients in Porto Alegre-RS.It is very similar to the study by Leão et  al. (2007), in which 10.7% were described in Juiz de Fora-MG (9,13) .However, when compared to data for the general population (1.38%), this seroprevalence of hepatitis C found in patients with renal failure undergoing hemodialysis is considered high (14,15) .An important cause of HCV infection in hemodialysis is the practice of transfusion of blood and/or blood components.The study by Yonemura et al. verified that from 52 patients who had undergone transfusion, 21 (40.4%) were HCV-antibody positive, while among the 182 patients with no history of transfusion, just 20 (11%) had this antibody.These data may be compared to the study by Hinrichsen et al., which also verified increased prevalence of anti-HCV antibody in patients undergoing multiple transfusions (10,20) .Another factor possibly related to the increase of this prevalence is the duration of dialysis treatment, as observed in other works (6,16,19) .This demonstrates the importance of public health strategies, as anti-HCV screening by the nucleic acid test (NAT) in blood donors, and recommendations for prevention and control of hepatitis C at dialysis units, as well as guidance on the reuse of dialyzers, now converted to single use according to a resolution of the National Agency of Sanitary Surveillance (ANVISA), RDC nº.11, of March 11, 2014 (2,5,7,8,11,14) .
In summary, the obtained results showed a decreased prevalence of hepatitis C when in comparison to studies from the latest years, yet this prevalence is still very high if contrasted with the 1.38% of the general population (3) .Thus, rigorous observance of universal precaution guidelines is necessary to reduce transmission of HCV infection in hemodialysis units.Among the processes are the correct and rigorous disinfection of machines and equipment, precautions for the reuse of dialyzers, and an effective biosecurity control by the health staff.It is very important to keep rigorous screening control on the use of blood components, for instance, the employment of techniques such as NAT, aiming at improving sensitivity in the identification  of HCV and HIV infections.We also highlight the necessity of early diagnosis in primary attention, and of health policies designed to track and monitor cases of hepatitis C in the general population.
Besides, a prospective follow-up of hemodialysis patients is also essential so as to identify the actual risk factors for contamination by this disease. rEfErEnCES

tABLE 1 -
(4)olute and relative distribution by sex, age group, city, color, mean and SD of age, HCV infection, HIV infection and HCV/HIV coinfection for the group of 649 patients(4) SD: standard deviation; HCV: hepatitis C virus; HIV: human immunodeficiency virus.

tABLE 3 -
(4)olute and relative distribution by sex, age group, city and ethnicity/race, and mean age and SD of age for the group of 12 patients with HIV/HCV coinfection(4) SD: standard deviation; HIV: human immunodeficiency virus; HCV: hepatitis C virus.