Astragalus (a traditional Chinese medicine) for treating chronic kidney disease

Astragalus (Radix Astragali, huang qi) is the dried root of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao or Astragalus membranaceus (Fisch.) Bge. (Family Leguminosae). It is one of the most widely used herbs in traditional Chinese medicine for treating kidney diseases. Evidence is needed to help clinicians and patients make judgments about its use for managing chronic kidney disease (CKD).

This review evaluated the benefits and potential harms of Astragalus for the treatment of people with CKD.

We searched the Cochrane Renal Group's Specialised Register to 10 July 2014 through contact with the Trials' Search Co-ordinator using search terms relevant to this review. We also searched CINAHL, AMED, Current Controlled Trials, OpenSIGLE, and Chinese databases including CBM, CMCC, TCMLARS, Chinese Dissertation Database, CMAC and Index to Chinese Periodical Literature.

Randomised controlled trials (RCTs) and quasi-RCTs comparing Astragalus, used alone as a crude herb or an extract, with placebo, no treatment, or conventional interventions were eligible for inclusion.

Two authors independently extracted data and assessed risk of bias in the included studies. Meta-analyses were performed using relative risk (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes, with 95% confidence intervals (CI).

We included 22 studies that involved 1323 participants, of whom 241 were receiving dialysis treatment. Risk of bias was assessed as high in six studies, and unclear in the remaining 16 studies. Study quality was low overall.Our nominated primary outcomes of time to requirement for renal replacement therapy (RRT) or initiation of dialysis and all-cause mortality were not reported in any of the included studies.Results concerning the effects of Astragalus on kidney function were inconsistent. Astragalus significantly increased CrCl at end of treatment (4 studies, 306 participants: MD 5.75 mL/min, 95% CI 3.16 to 8.34; I² = 0%), decreased SCr (13 studies, 775 participants: MD -21.39 µmol/L, 95% CI -34.78 to -8; I² = 70%) and especially in those whose baseline SCr was < 133 µmol/L in particular (3 studies, 187 participants: MD -2.52 µmol/l, 95% CI -8.47 to 3.42; I² = 0%). Astragalus significantly decreased 24 hour proteinuria at end of treatment (10 studies, 640 participants; MD -0.53 g/24 h, 95% CI -0.79 to -0.26; I² = 90%); significantly increased haemoglobin levels overall (4 studies, 222 participants): MD 9.51 g/L, 95% CI 4.90 to 14.11; I² = 0%) and in haemodialysis patients in particular (3 studies, 142 participants: MD 11.20 g/L, 95% CI 5.81 to 16.59; I² = 0%). Astragalus significantly increased serum albumin (9 studies, 522 participants: MD 3.55 g/L, 95% CI 2.33 to 4.78; I² = 65%). This significant increase was seen in both dialysis (3 studies, 152 participants): MD 4.04 g/L, 95% CI 1.91 to 6.16; I² = 72%) and non-dialysis patients (6 studies, 370 participants: MD 3.24 g/L, 95% CI 1.70 to 4.77; I² = 61%). Astragalus significantly decreased systolic blood pressure (2 studies, 77 participants: MD -16.65 mm Hg, 95% CI -28.83 to -4.47; I² = 50%), and diastolic blood pressure (2 studies, 77 participants: MD -6.02 mm Hg, 95% CI -10.59 to -1.46; I² = 0%).Six of 22 included studies reported no adverse effects were observed; while the remaining 16 studies did not report adverse effects.

Although Astragalus as an adjunctive treatment to conventional therapies was found to offer some promising effects in reducing proteinuria and increasing haemoglobin and serum albumin, suboptimal methodological quality and poor reporting meant that definitive conclusions could not be made based on available evidence.