Vitamin D Supplementation and Hemoglobin Levels in Hypertensive Patients: A Randomized Controlled Trial

Abstract EN

Epidemiological evidence suggests that circulating 25-hydroxyvitamin D (25OHD) levels are inversely associated with hemoglobin (Hb) levels and anemia risk.

We evaluated whether vitamin D supplementation improves Hb levels and reduces anemia risk in hypertensive patients.

Two hundred patients with 25OHD levels <75 nmol/L who attended the Styrian Vitamin D Hypertension Trial were included, of whom 188 completed the trial.

Patients randomly received 2800 IU vitamin D3 daily or a matching placebo for eight weeks.

Initially, the prevalence of anemic status (Hb levels <12.5 g/dL) and deficient 25OHD levels (<30 nmol/L) was 6.5% and 7.5%, respectively.

All anemic patients had 25OHD levels >50 nmol/L.

The mean (95% confidence interval) vitamin D effect on Hb levels was 0.04 (−0.14 to 0.22) g/dL ( P = 0.661 ).

Moreover, vitamin D treatment did not influence anemic status significantly ( P > 0.999 ).

Likewise, vitamin D had no significant effect on Hb levels in the subgroups of anemic patients or in patients with initial 25OHD levels <30 nmol/L.

In conclusion, a daily vitamin D supplement of 2800 IU for eight weeks did not improve Hb levels or anemic status in hypertensive patients.

Future trials should focus on anemic patients with deficient 25OHD levels (e.g., <30 nmol/L).

This trial is registered with clinicaltrials.gov [NCT02136771].