Vitamin D administration boosts FGF23 concentrations

Administration of vitamin D or activated vitamin D >2,000 IU/day leads to a significant increase in concentrations of phosphaturic hormone fibroblast growth factor 23 (FGF23), a risk marker of cardiovascular and all-cause mortality, particularly in patients with end-stage renal disease (ESRD) or heart failure (HF), a study has shown.

The investigators performed a systematic review and meta-analysis of randomized, placebo-controlled trials in multiple databases from inception to January 2020 to synthesize evidence for the effect of vitamin D administration on circulating FGF23 concentrations. Seventy-three records were identified for full-text review; 21 articles and 23 studies qualified for the final analysis.

Eligible studies included a total of 1,925 participants with follow-up of 8 to 156 weeks. The weighted mean difference in FGF23 between vitamin D and placebo groups was 21 pg/ml (95 percent confidence interval [CI], 13–28; p<0.001), with significant heterogeneity among studies (I², 99 percent).

Patients with ESRD or HF had a higher increment in FGF23 concentrations than other individuals (300 pg/ml, 95 percent CI, 41–558 vs 20 pg/ml, 95 percent CI, 12–28; p_interaction=0.03), as did those with baseline 25-hydroxyvitamin D concentrations <50 vs ≥50 nmol/l (34 pg/ml, 95 percent CI, 18–51 vs 9 pg/ml, 95 percent CI, 3–14; p_interaction=0.002).

FGF23 increment was also affected by vitamin D dose/type (vitamin D dose equivalent ≤2,000 IU/day: 2 pg/ml, 95 percent CI, 0–3; vitamin D dose equivalent >2,000 IU/day: 18 pg/ml, 95 percent CI, 6–30; administration of activated vitamin D: 67 pg/ml, 95 percent CI, 16–117; p_interaction=0.001).

On the other hand, study duration (p_interaction=0.14), age class (p_interaction=0.09), or assay provider (p_interaction=0.11) did not significantly influence the results.