Cristian Paul Leon Rabanal; Dr. Javier Cieza Zevallos; Roberto Cieza Cusato
Objective: Cardiovascular diseases are the most important causes of mortality in patients with end-stage renal disease. However, viral infections (hepatitis B and C) have acquired great importance for patients undergoing hemodialysis, because they affect patients' survival and increase morbidity and mortality. This study aimed at assessing the influence of hepatitis C on the mortality of patients undergoing hemodialysis. Methods: This is a non-concurrent cohort study during a period of ten years. Results: Each cohort comprised 74 patients. Hepatitis C did not increase the risk of death, and the survival of infected patients was better than that of patients without hepatitis C. The one-year and five-year survivals of non-infected patients were 93.9% and 52.3%, respectively, while those of noninfected patients were 95.5% and 73.1%, respectively (Cox-Mantel log-rank, p = 0.02). Conclusion: No increase in mortality risk was observed. Hepatitis C did not correlate with an increase in mortality in patients with end-stage renal disease undergoing hemodialysis.
Descriptors: chronic kidney failure, hepatitis C, mortality, renal dialysis.
Objetivo: As causas mais importantes de mortalidade em pacientes com Doença Renal Crônica Terminal (DRCT) são as doenças cardiovasculares. No entanto, existem doenças infecciosas virais (hepatite B e C) que se tornaram uma questão de grande importância para pacientes em hemodiálise, pois afetam a sua sobrevida aumentando a morbidade e a mortalidade. Nosso objetivo foi estudar a influência da hepatite C na mortalidade em pacientes em hemodiálise. Métodos: Realizamos um estudo de coorte não concorrente durante 10 anos. Resultados: Foram estudados 74 pacientes em cada coorte. A hepatite C não aumentou o risco de morte nos pacientes e a sobrevida dos pacientes com essa infecção foi melhor do que no grupo sem hepatite C. A sobrevida em pacientes não infectados no primeiro e quinto anos foi de 93,9% e 52,3%; e para os não infectados foi de 95,5% e 73,1%, respectivamente (Log Rank Mantel Cox, p = 0,02). Conclusão: Não encontramos aumento no risco de mortalidade. A hepatite C não se correlaciona com aumento de mortalidade em pacientes com DRCT em programa de hemodiálise.
Descritores: insuficiência renal crônica, hepatite C, mortalidade, diálise renal.
In the past 20 years, cardiovascular complications were recognized as the major cause of mortality in hemodialysis (HD) patients. The presence of chronic infection has generated a series of speculations about its importance for the final status of patients undergoing that type of renal replacement therapy. Of the chronic infections, those caused by different hepatitis viruses have gained attention. Regarding the hepatitis B virus, policies of systematic vaccination and the establishment of strict biosafety measures in HD units related to hepatitis B have succeeded in controlling that infection with the virtual elimination of the problem among patients undergoing chronic dialysis. The same did not occur with hepatitis C, initially described as hepatitis non-A, non-B, and later, in 1989, identified as C.1,2
The accuracy of the test for detecting the hepatitis C viral DNA in past years has allowed for the successful identification of that virus in the epidemiological chain of blood banks and the limitation of its transmission in chronic patients undergoing HD. Nevertheless, it could neither prevent a period of rapid spread of the disease in HD units, nor recognize other relevant aspects for the transmission that do not depend on blood transfusion and that could not be interfered with.2
Although those problems have been solved, the effect of hepatitis C on the mortality of chronic patients undergoing HD has been studied and, apparently, that effect is controversial or does not exist. However, some studies have shown an increase in the mortality risk as compared with that of patients with no hepatitis C. That risk is associated with an increase in cardiovascular mortality in patients under the age of 65 years. Whether that effect is due to inflammation or to liver disease has not been clarified.3,4,5,6
Chronic patients undergoing HD have shown characteristics specific to each country and population. Such differences can be established to each regional and local level, and, thus, the effect on lethality can differ according to each particular situation.6
In Peru, some specific situations related to hepatitis C in HD services should be emphasized. For example, the epidemics characterized by infection rates of as much as 70% or more in the 1990s 12 has drastically decreased in past years because of the health policies established to improve laboratory services provided to groups of potential blood donors infected with hepatitis C virus (HCV). Another measure was the isolation of patients with HCV infection in special units, generating HD units intended for the exclusive treatment of either infected or non-infected patients, limiting the number of infected patients in each unit.12,13,14
That policy, initially made in a intuitive manner, was successful, as previously reported.14 Now we need to study, in our population, the effect of seropositivity for hepatitis C on lethality, controlling critical variables, using a study of cohorts, because the previous study assessed a small number of individuals with a low incidence of seroconversion (from negative to positive).
The problem of prevalence of hepatitis C and its effect on time in populations like ours need to be solved, so that pharmacological actions to enhance survival can be initiated, even though that intervention is controversial in the international literature.
This study aimed at assessing the existence of an association between the presence of positive markers for hepatitis C and mortality in our population.
This is a non-concurrent cohort study involving two cohorts of patients undergoing chronic HD at a HD center in the city of Lima, Peru, from January first, 1985, to December 31st, 2007. We assumed that hepatitis C could increase the relative risk of death by one and a half time, accepting a mortality rate of the general population of 50% during a five-year follow- -up in the HD program.
The calculated sample was 65 patients in each cohort, with one exposed patient (HCV-infected) to one non-exposed patient (non HCV-infected), and the sample was increased in 10% to prevent bias with data loss. Thus, the final size of each cohort was defined as 74 patients.
Analysis of mortality adjusted to the variables sex, age, and etiology of the underlying disease was performed to avoid biases that could influence mortality. Analysis of survival was performed by use of the Kaplan Meier risk curve, log-rank test, and Cox multivariate analysis. The results that achieved a statistically significant value (p < 0.05) are shown in tables and survival curves.
Seventy-four patients were studied in each cohort. The general data of the cohorts are shown in Table 1. No statistically significant difference was observed in the control variables of the cohorts. Thus, there are two comparable groups for analysis in the model of adjusted mortality, in which the variables that could influence the final result were controlled.