DISCUSSION
This review aimed to determine if AST-120 is effective in delaying the
progression of CKD by measuring outcomes including incidence of
all-cause mortality, incidence of ESRD requiring renal replacement
therapy, and doubling of serum creatinine. Results showed that there is
no significant difference in the incidences of the three primary
endpoints between patients given AST-120 and those given routine
treatment alone.
Despite the current availability of a commercially-marketed preparation
of AST-120, the results obtained in this meta-analysis do not support
its use for the purpose of preventing death or delaying the time to
initiation of ESRD among patients with CKD. Some trials could have shown
an advantage of using AST-120 in terms of slowing the rate of increase
in serum creatinine among CKD patients; however, this outcome is
clinically insignificant since the levels of serum creatinine alone are
not the sole determinant of overall well-being in actual clinical
settings. Thus, the finding of dampened increase in the rate of serum
creatinine with the use of AST-120 does not justify its use among
patients with CKD. It would be more meaningful to assess the benefit of
using AST-120 in terms of its effect on clinically significant outcomes
such as mortality and incidence of RRT.
Several factors may have contributed to the lack of significant effects
of AST-120. First is the possibility of advanced disease in many
participants (as evidenced by a significant percentage reaching the
primary outcome) that may not be effectively altered or reversed by
AST-120 anymore. Second, the varying dosages of AST-120 used in
different studies may have contributed to the wide range of results. The
incidence of adverse effects, though reported in several studies, were
not pooled and analyzed due to differences in reporting of these data.
Despite the insignificant findings in this meta-analysis, other areas
regarding the potential beneficial use of AST-120 may still be explored.
For future studies, it might be helpful to stratify study populations
based on the dose of AST-120, as there could be a potential
dose-dependent clinical benefit in using AST-120 after all. Also,
stratification based on stage of CKD may also be done, as the magnitude
of the effect of AST-120 may be dependent on CKD stage. It could be
possible that the use of AST-120 might after all be clinically
advantageous when initiated at the earlier stages of CKD.