Impact of Hepatitis C on Survival in Dialysis Patients
Impact of Hepatitis C on Survival in Dialysis Patients
Our electronic and manual searches identified 425 studies that were selected for full text review; of which 201 were considered potentially relevant and were selected for full text review (Fig. 1). Thirteen papers (giving information on fourteen observational studies) fulfilled the inclusion criteria and 188 were excluded. The paper by Johnson et al. reported information on two studies from Japan and Australia/New Zealand, respectively. There were three case–control and ten cohort studies. One paper was concerned with acute hepatitis C in 19 patients on maintenance dialysis; 15 (79%) evolved to chronic HCV. Four papers investigated the relationship between HCV infection and death from a population perspective. The list of the 201 references is available from the authors on request.
(Enlarge Image)
Figure 1.
Flow diagram of studies considered for inclusion in the meta-analysis.
A total of fourteen studies involving 145 608 unique patients were included in our meta-analysis. There was a 100% concordance between reviewers with respect to final inclusion and exclusion of studies reviewed based on the predefined inclusion and exclusion criteria.
Shown in Table 1 & Table 2 are some salient demographic characteristics of subjects enrolled in the included studies. Three were from centres in North America, five from Western Europe, three from Asia and two from Australia/New Zealand. The mean age of subject cohorts was between 40 and 68.7 ± 14.5 years of age. The gender distribution varied from 45.6 to 71.5% male. The rate of patients with diabetes mellitus ranged from 4.5 to 45%. Six studies addressed HD patients only. The average follow-up was between 24 months and 10 years. Information on the rate of dialysis patients undergoing renal transplantation (RT) over the follow-up period was given in 8 (57%) studies. The frequency of patients who underwent RT ranged from 0 to 60.8%. The frequency of anti-HCV-positive patients varied from 1.6 to 44.9%.
Detailed information on the all-cause mortality rate of the patients was reported in fourteen studies. All included studies used Cox proportional hazard models to adjust for differential follow-up times and distribution of potential confounders in isolating the effect of anti-HCV seropositive status on all-cause mortality. Presence of anti-HCV antibody in serum was an independent prognostic factor for all-cause mortality in most studies, although sometimes of borderline statistical significance.
As listed in Table 3, the summary estimate for aRR of all-cause mortality with anti-HCV across the identified studies was 1.35 with a 95% CI of 1.25–1.47. Tests for homogeneity of the aRR across the fourteen studies gave Ri value of 0.39, that is, the homogeneity assumption was not rejected. As shown in Table 3, there was no substantial difference in pooled aRR across designs (i.e. cohort, US, population-based studies, etc).
Four studies reported data on liver disease-related mortality, the summary estimate for aRR being 3.82 with 95% CI of 1.82–7.61 (Table 4). Tests for homogeneity of the aRR across the four studies gave an Ri value of 0.58, but the P-value (by Q-test) was not significant. Information on cardiovascular death rate was given in three studies, the summary estimate for aRR was 1.26 (95% CI, 1.10–1.45), and no heterogeneity was found (P-value by Q-test = 0.73). Data on the death rate because of infections were given in two studies; the point estimate for aRR was 1.53 (95% CI, 1.11; 2.12); the homogeneity assumption was not rejected (P-value by Q-test = 0.85).
The funnel plot shown in Fig. 2 suggests no publication bias.
(Enlarge Image)
Figure 2.
Hepatitis C virus and survival in dialysis: funnel plot.
Results
Literature Review
Our electronic and manual searches identified 425 studies that were selected for full text review; of which 201 were considered potentially relevant and were selected for full text review (Fig. 1). Thirteen papers (giving information on fourteen observational studies) fulfilled the inclusion criteria and 188 were excluded. The paper by Johnson et al. reported information on two studies from Japan and Australia/New Zealand, respectively. There were three case–control and ten cohort studies. One paper was concerned with acute hepatitis C in 19 patients on maintenance dialysis; 15 (79%) evolved to chronic HCV. Four papers investigated the relationship between HCV infection and death from a population perspective. The list of the 201 references is available from the authors on request.
(Enlarge Image)
Figure 1.
Flow diagram of studies considered for inclusion in the meta-analysis.
A total of fourteen studies involving 145 608 unique patients were included in our meta-analysis. There was a 100% concordance between reviewers with respect to final inclusion and exclusion of studies reviewed based on the predefined inclusion and exclusion criteria.
Patient Characteristics
Shown in Table 1 & Table 2 are some salient demographic characteristics of subjects enrolled in the included studies. Three were from centres in North America, five from Western Europe, three from Asia and two from Australia/New Zealand. The mean age of subject cohorts was between 40 and 68.7 ± 14.5 years of age. The gender distribution varied from 45.6 to 71.5% male. The rate of patients with diabetes mellitus ranged from 4.5 to 45%. Six studies addressed HD patients only. The average follow-up was between 24 months and 10 years. Information on the rate of dialysis patients undergoing renal transplantation (RT) over the follow-up period was given in 8 (57%) studies. The frequency of patients who underwent RT ranged from 0 to 60.8%. The frequency of anti-HCV-positive patients varied from 1.6 to 44.9%.
Summary Estimates of Outcome
Detailed information on the all-cause mortality rate of the patients was reported in fourteen studies. All included studies used Cox proportional hazard models to adjust for differential follow-up times and distribution of potential confounders in isolating the effect of anti-HCV seropositive status on all-cause mortality. Presence of anti-HCV antibody in serum was an independent prognostic factor for all-cause mortality in most studies, although sometimes of borderline statistical significance.
As listed in Table 3, the summary estimate for aRR of all-cause mortality with anti-HCV across the identified studies was 1.35 with a 95% CI of 1.25–1.47. Tests for homogeneity of the aRR across the fourteen studies gave Ri value of 0.39, that is, the homogeneity assumption was not rejected. As shown in Table 3, there was no substantial difference in pooled aRR across designs (i.e. cohort, US, population-based studies, etc).
Four studies reported data on liver disease-related mortality, the summary estimate for aRR being 3.82 with 95% CI of 1.82–7.61 (Table 4). Tests for homogeneity of the aRR across the four studies gave an Ri value of 0.58, but the P-value (by Q-test) was not significant. Information on cardiovascular death rate was given in three studies, the summary estimate for aRR was 1.26 (95% CI, 1.10–1.45), and no heterogeneity was found (P-value by Q-test = 0.73). Data on the death rate because of infections were given in two studies; the point estimate for aRR was 1.53 (95% CI, 1.11; 2.12); the homogeneity assumption was not rejected (P-value by Q-test = 0.85).
The funnel plot shown in Fig. 2 suggests no publication bias.
(Enlarge Image)
Figure 2.
Hepatitis C virus and survival in dialysis: funnel plot.
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