A daily dose of folic acid, when used together with the drug Vasotec (enalapril), may significantly delay the progression of chronic kidney disease (CKD), according to a study published in the journal JAMA Internal Medicine.

The results, reported in an article titled “Efficacy of Folic Acid Therapy on the Progression of Chronic Kidney Disease,” come from the renal sub-study of a randomized, double-blind clinical trial called the China Stroke Primary Prevention Trial (CSPPT).

The aim of the sub-study was to investigate whether treatment with Vasotec plus folic acid is more effective in slowing renal function decline than Vasotec alone among adults with hypertension who live in areas without folic acid fortification.

The trial recruited more than 15,000 participants ages 45 to 75, of which 1,671 had chronic kidney disease. The participants were randomly divided into two groups: Those in the first group were given Vasotec only as a 10 mg tablet every day, while those in the second group were given a tablet containing the same amount of Vasotec plus 0.8 mg folic acid. Neither clinicians nor the participants knew who was taking which tablet (double-blind).

To monitor CKD progression, researchers measured the estimated glomerular filtration rate (eGFR), a test that measures the level of kidney function and can determine the stage of kidney disease.

They found that eGFR decreased in 164 people taking Vasotec only, compared to 132 people taking Vasotec as well as folic acid. The researchers calculated that people in the Vasotec plus folic acid group had a 21 percent reduction in the risk of progression of chronic kidney disease and a slower rate of eGFR decline.

The greatest effect of folic acid treatment was seen in people who had mild to moderate CKD at baseline. No significant differences were seen among people who did not have CKD.

The scientists concluded that folic acid could slow the decline of eGFR and the progression of chronic kidney disease.