Folic acid may reduce odds of CKD progression, but only in select patients
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Combining enalapril with folic acid supplementation reduced odds of chronic kidney disease progression in patients with CKD, according to this study. However, this potential benefit was seen only in patients with baseline B12 levels of at least 248 pmol/L.
“The renal sub-study of the China Stroke Primary Prevention Trial (CSPPT) suggested that folic acid treatment can significantly delay the progression of CKD by 55% among hypertensive patients with mild to moderate CKD,” Youbao Li, MD, of Nanfang Hospital at Southern Medical University in China, and colleagues wrote. “Nevertheless, the effect of naturally occurring serum B12, without supplements, on the association between folic acid treatment and CKD progression has not been tested in previous studies. As such, the current study aimed to address this question in a post hoc analysis of the renal sub-study of the CSPPT.”
For the post hoc analysis, researchers included 1,374 adults with hypertension, CKD and baseline B12 measurements (mean eGFR at baseline, 86.1 mL/min/1.73m2). Patients were categorized into tertiles based on B12 levels (<244 pmol/L, 244 pmol/L to <323 pmol/L or 323 pmol/L) and randomly assigned to either 10 mg of enalapril and 0.8 mg of folic acid per day or 10 mg of enalapril only. Median treatment duration was 4.4 years. The primary outcome was progression of CKD, which researchers defined as a decrease in eGFR of at least 30% if baseline eGFR was at least 60 mL/min/1.73m2 or a decrease of at least 50% if baseline eGFR was less than 60 mL/min/1.73m2.
Researchers found that, compared to enalarpril alone, enalapril-folic acid treatment was associated with an 83% reduction in the odds of CKD progression for those with B12 levels of at least 248 pmol/L. There was, however, no significant difference observed between groups for those with baseline B12 levels less than 248 pmol/L (considered a “metabolic B12 deficiency”).
“Our study demonstrates that baseline B12 levels significantly modify the relation of folic acid treatment to CKD progression in hypertensive patients with mild to moderate CKD,” the researchers wrote. They suggested that further investigation be done to examine the potential benefits of combining B12 (as methylcobalamin) with folic acid for patients with lower B12 levels.
In a related editorial, Angela Yee-Moon Wang, MD, PhD, of Queen Mary Hospital at the University of Hong Kong, argued that the medical community should be cautious when interpreting results from a post hoc subgroup analysis because “RCTs remain the gold-standard study design to generate the best evidence to inform clinical practice.”
She continued, “While awaiting more evidence, it seems reasonable to supplement patients with CKD who have a confirmed folic acid or B-group vitamin deficiency. However, there is insufficient evidence to support regular use of folic acid and B-group vitamins for kidney protection.” – by Melissa J. Webb
Disclosures: Li reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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