Background: The prevalence of hepatitis C in patients with end stage renal disease, under renal replacement therapy either with hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD), is higher than in the general population. The prevalence of hepatitis C in patients under dialysis, however, is unknown in Mexico. Thus, the major goals of the present study were to determine the prevalence of hepatitis C in our patients on dialysis, and the risk factors associated with it.
Methods: We performed a cross-sectional and comparative study in patients under dialysis in three hospital centers in the south of Mexico City. For every patient we evaluated: age, gender, etiology of the renal failure, modality and time in dialysis, transfusion and surgical history, serum albumin, aminotranferases, BUN, and serum creatinine. The presence of hepatitis C was assessed by ELISA II and qualitative RT-PCR in blood samples. In all patients diagnosed as having hepatitis C, RT-PCR to amplified part of the virus genome was also carried out in the dialysis fluid.
Results: We studied 235 dialysis patients that were classified according to their dialysis modality in: 132 patients under CAPD, 17 under CAPD and history of HD (PD/HD) and 86 under HD. The time under dialysis was different between the study groups: CAPD 29.6 +/- 22.3 months, PD/HD 39 +/- 42.3 and HD 14.2 +/- 15.6 (p < 0.01). The presence of hepatitis C was detected in 24 of the 235 patients, for a global prevalence of 10.2%. In no case was viral RNA found in the dialysis fluid. The prevalence varied, however, according to the type of dialysis. It was in the CAPD group 4.5%, 12.7% in the HD group, and 41.1% in the PD/HD group (p < 0.001). The multivariate analysis showed that the risk factors for hepatitis C are transfusions before the year of 1991 (Odds Ratio = 6.4), and history of hepatitis (OR = 4.3). Since less patients are seen with transfusions before 1991, we constructed another model in which this variable was excluded. This new multivariate model showed that history of surgery (OR = 4.4), the use of HD as the dialysis modality (OR = 3.5), and prolonged time under dialysis (OR = 1.01) were all significantly associated with the presence of hepatitis.
Discussion: Our results show that the prevalence of hepatitis C is lower in our patients that the prevalence reported by many others (average of other countries 18.5%). Since we found a higher prevalence in HD than in CAPD, even with the lower time under dialysis in the HD group, it is possible that our lower overall prevalence is secondary to the fact that CAPD is the most frequent mode of dialysis in our country. We observed the highest prevalence in the PD/HD group, that is probably due to longer exposure to the risk factors. The association with transfusions before 1991 indicates that the infection was acquired in some patients before dialysis was started. Our results showed that the CAPD is the dialysis technique with lower risk of hepatitis C infection.