Association of herbal and dietary supplements with progression and complications of chronic kidney disease: a prospective cohort study.

OBJECTIVE

To determine associations between herbal and dietary supplement (HDS) use and the progression of chronic kidney disease (CKD), and associations of HDS with uncontrolled hyperphosphataemia in patients with CKD.

METHODS

The cohort study recruited 406 Thai outpatients with stage 3-5 CKD from two kidney clinics of which 357 were followed up over 12 months. Patients receiving renal replacement therapy prior to recruitment were excluded. Participants were interviewed regarding their HDS use, dietary intake and conventional medication adherence using a questionnaire. The primary outcome was a composite of a decline of at least 5 mL/min per 1.73 m2 per year of estimated glomerular filtration rate and end stage renal disease. Serum creatinine, serum levels of potassium and phosphate were extracted from their medical notes over the 12 months. χ2 tests and multiple logistic regression analyses were performed to ascertain any associations.

RESULTS

Despite no association between HDS and the progression of CKD over a one-year period (adjusted odds ratio (OR) 1.16, 95% confidence interval (CI) 0.66-2.03), two patients had acute kidney injury, which may be related to an unknown Chinese herbal medicine, or river spiderwort combined with diclofenac reported in the medical notes. The use of HDS was associated with uncontrolled hyperphosphataemia (adjusted OR 3.53, 95%CI 1.20-10.43).

CONCLUSIONS

The findings suggest that HDS are likely to be related to acute kidney injury rather than the progression of CKD in Thai patients with CKD. The products were associated with uncontrolled hyperphosphataemia. Patients who have CKD and use HDS should be closely monitored regarding their kidney function and electrolytes.