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.