Risks of kidney failure associated with consumption of herbal products containing Mu Tong or Fangchi: a population-based case-control study.

Background: Taiwan has a remarkably high incidence of end-stage renal disease (ESRD). The objective of this study is to determine the association between prescribed herbal products containing aristolochic acid and ESRD.

Study Design: Population-based case-control study.

Setting & Participants: All new ESRD cases in Taiwan and a simple random sample (200,000 people) drawn from the national health insurance reimbursement database in 1997-2002.

Predictor: Age; sex; hypertension; diabetes; cumulative doses of nonsteroidal anti-inflammatory drugs, acetaminophen, and adulterated herbal supplements potentially containing aristolochic acid before the development of chronic kidney disease; and indications for prescribing such herbs, including chronic hepatitis, chronic urinary tract infection, chronic neuralgia, or chronic musculoskeletal diseases.

Outcomes & Measurements: Occurrence of ESRD through construction of multiple logistic regression models.

Results: There were 36,620 new ESRD cases from 1998 through 2002. After exclusion of cases with chronic kidney disease diagnosed before July 1, 1997, there were 25,843 new cases of ESRD and 184,851 controls in the final analysis. Women, older age, hypertension, and diabetes were significantly associated with increased risks of the development of ESRD. After adjustment for known risk factors, cumulative doses >60 g of Mu Tong (OR, 1.47 [95% CI, 1.01-2.14] for 61-100 g; OR, 5.82 [95% CI, 3.89-8.71] for >200 g) or Fangchi (OR, 1.60 [95% CI, 1.20-2.14] for 61-100 g; OR, 1.94 [95% CI, 1.29-2.92] for >200 g) were associated with increased risk of the development of ESRD with a dose-response relationship. This relationship persisted when analyses were limited to participants who consumed <500 pills of nonsteroidal anti-inflammatory drugs and those without diabetes.

Limitations: No measurement of renal function, no contact with patients, over-the-counter sales were not recorded, and potential underestimation of exposure dose for cases and ORs.

Conclusions: Consumption of >60 g of Mu Tong or Fangchi from herbal supplements was associated with an increased risk of developing kidney failure.