Vitamin D Supplementation and Hemoglobin Levels in Hypertensive Patients: A Randomized Controlled Trial
Table 2
Results of vitamin D treatment on hematological parameters, calcium and phosphate metabolism, and additional parameters in hypertensive subjects.
Characteristics
Vitamin D group ()
Placebo group ()
Treatment effect
value2
Baseline
Follow-up (8 weeks)
Mean change from baseline1
Baseline
Follow-Up (8 weeks)
Mean change from baseline1
Hematological parameters
Hemoglobin (g/dL)
14.4 ± 1.3
14.3 ± 1.3
−0.1 (−0.18 to 0.05)
14.4 ± 1.4
14.3 ± 1.3
−0.1 (−0.25 to 0.04)
0.04 (−0.14 to 0.22)
0.661
Hematocrit (%)
41.1 ± 3.2
41.1 ± 3.3
0.02 (−0.31 to 0.36)
41.5 ± 3.5
41.3 ± 3.2
−0.2 (−0.59 to 0.19)
0.16 (−0.33 to 0.65)
0.514
Erythrocytes (1012/L)
4.8 ± 0.4
4.8 ± 0.4
−0.02 (−0.05 to 0.02)
4.9 ± 0.4
4.8 ± 0.4
−0.04 (−0.09 to 0.00)
0.01 (−0.05 to 0.07)
0.691
MCV (µm3)
86.4 ± 4.3
86.7 ± 4.6
0.3 (−0.14 to 0.72)
85.6 ± 4.0
86.0 ± 4.0
0.3 (−0.09 to 0.77)
0.01 (−0.59 to 0.61)
0.971
MCH (pg Hb/RBC)
30.2 ± 1.8
29.9 ± 1.7
−0.04 (−0.16 to 0.08)
29.7 ± 1.6
29.7 ± 1.6
0.05 (−0.07 to 0.18)
−0.08 (−0.25 to 0.09)
0.890
MCHC (g/L)
35.0 ± 1.0
34.8 ± 1.1
−0.2 (−0.3 to 0.00)
34.7 ± 1.1
34.7 ± 1.1
−0.09 (−0.3 to 0.09)
−0.01 (−0.24 to 0.22)
0.938
Leucocytes (109/L)
5.9 (5.1–7.0)
6.0 (5.0–7.2)
0.04 (−0.18 to 0.26)
6.0 (5.0–7.5)
5.8 (5.0–6.9)
−0.1 (−0.31 to 0.12)
−0.13 (−0.17 to 0.42)
0.291
Platelets (109/L)
237 ± 62
240 ± 64
2.9 (−1.6 to 7.4)
231 ± 50
232 ± 53
1.7 (−3.8 to 7.1)
1.6 (−5.4 to 8.6)
0.651
Mean platelet volume (fl)
10.7 ± 1.0
10.7 ± 0.9
0.01 (−0.08 to 0.09)
10.8 ± 0.9
10.8 ± 0.9
−0.02 (−0.1 to 0.08)
0.01 (−0.12 to 0.13)
0.887
Calcium and phosphate metabolism
25-Hydroxyvitamin D (nmol/L)
54.9 ± 13.6
90.3 ± 18.3
35.4 (31.2 to 39.6)
50.8 ± 14.2
59.0 ± 22.1
8.1 (4.6 to 11.7)
28.7 (23.5 to 34.2)
<0.001
Parathyroid hormone (pmol/L)
5.2 (4.3–6.5)
4.8 (4.0–5.8)
−0.4 (−0.69 to −0.17)
5.4 (4.1–6.8)
5.3 (4.1–7.0)
0.18 (−0.13 to 0.49)
−0.60 (−0.99 to −0.22)
0.003
Phosphate (mg/mL)
2.9 ± 0.5
3.0 ± 0.5
0.1 (0.02 to 0.22)
3.0 ± 0.5
3.1 ± 0.5
0.09 (−0.02 to 0.19)
−0.01 (−0.14 to 0.11)
0.823
Calcium (mmol/L)
2.37 ± 0.1
2.37 ± 0.1
0.00 (−0.02 to 0.02)
2.37 ± 0.1
2.35 ± 0.1
−0.01 (−0.03 to 0.01)
−0.01 (−0.03 to 0.01)
0.259
Additional parameters
C-reactive protein (mg/L)
2.1 (0.9–3.8)
2.2 (1.0–4.2)
0.3 (−0.6 to 1.2)
1.4 (0.8–3.0)
1.4 (0.6–4.1)
0.2 (−0.2 to 0.6)
0.15 (−0.69 to 1.2)
0.598
eGFR (mL/min/1.732)
80.5 ± 18.1
77.9 ± 18.8
−2.7 (−5.0 to −0.4)
77.5 ± 17.6
76.7 ± 16.9
−0.9 (−3.0 to 1.3)
−1.3 (−4.3 to 1.7)
0.398
1Change from baseline data is shown as means and 95% confidence interval. 2ANCOVA with adjustments for baseline values was used to test for differences in the outcome variables between the vitamin D and the placebo group. MCV: mean corpuscular volume; MCH: mean corpuscular hemoglobin; Hb: hemoglobin; RBC: red blood cell; MCHC: mean corpuscular hemoglobin concentration; eGFR: estimated glomerular filtration rate.
