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Original Investigation
October 2016

Efficacy of Folic Acid Therapy on the Progression of Chronic Kidney DiseaseThe Renal Substudy of the China Stroke Primary Prevention Trial

Author Affiliations
  • 1National Clinical Research Center for Kidney Disease, Nanfang Hospital, Southern Medical University, Guangzhou, China
  • 2State Key Laboratory of Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
  • 3Guangdong Provincial Institute of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
  • 4Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
  • 5Department of Cardiology, Peking University First Hospital, Beijing, China

Copyright 2016 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.

JAMA Intern Med. 2016;176(10):1443-1450. doi:10.1001/jamainternmed.2016.4687

Importance  The efficacy of folic acid therapy on renal outcomes has not been previously investigated in populations without folic acid fortification.

Objective  To test whether treatment with enalapril and folic acid is more effective in slowing renal function decline than enalapril alone across a spectrum of renal function at baseline from normal to moderate chronic kidney disease (CKD) among Chinese adults with hypertension.

Design, Setting, and Participants  In this substudy of eligible China Stroke Primary Prevention Trial (CSPPT), 15 104 participants with an estimated glomerular filtration rate (eGFR) 30 mL/min/1.73 m2 or greater, including 1671 patients with CKD, were recruited from 20 communities in Jiangsu province in China.

Interventions  Participants were randomized to receive a single tablet daily containing 10 mg enalapril and 0.8 mg folic acid (n = 7545) or 10 mg enalapril alone (n = 7559).

Main Outcomes and Measures  The primary outcome was the progression of CKD, defined as a decrease in eGFR of 30% or more and to a level of less than 60 mL/min/1.73 m2 if the baseline eGFR was 60 mL/min/1.73 m2 or more, or a decrease in eGFR of 50% or more if the baseline eGFR was less than 60 mL/min/1.73 m2; or end-stage renal disease. Secondary outcomes included a composite of the primary outcome and all-cause death, rapid decline in renal function, and rate of eGFR decline.

Results  Overall, 15 104 Chinese adults with a mean (range) age of 60 (45-75) years were recruited; median follow-up was 4.4 years. There were 164 and 132 primary events in the enalapril group and the enalapril–folic acid group, respectively. Compared with the enalapril group, the enalapril–folic acid group had a 21% reduction in the odds of the primary event (odds ratio [OR], 0.79; 95% CI, 0.62-1.00) and a slower rate of eGFR decline (1.28% vs 1.42% per year; P = .02). Among the participants with CKD at baseline, folic acid therapy resulted in a significant reduction in the risks for the primary event (OR, 0.44; 95% CI, 0.26-0.75), rapid decline in renal function (OR, 0.67; 95% CI, 0.47-0.96) and the composite event (OR, 0.62; 95% CI, 0.43-0.90), and a 44% slower decline in renal function (0.96% vs 1.72% per year, P < .001). Among those without CKD at baseline, there was no between-group difference in the primary end point.

Conclusions and Relevance  Enalapril–folic acid therapy, compared with enalapril alone, can significantly delay the progression of CKD among patients with mild-to-moderate CKD.

Trial Registration Identifier: NCT00794885