Effect of oral sodium bicarbonate on fibroblast growth factor-23 in patients with chronic kidney disease: a pilot study

Table 2 Effect of sodium bicarbonate therapy

	Initial	2-week placebo	p-value
Serum Bicarbonate (mEq/L)	23.0 ± 2.3	22.2 ± 2.8	0.17
FGF23 (RU/mL)	157.4 (90.2–289.4)	161.7 (104.5–245.5)	0.91
	Before sodium bicarbonate^a	After sodium bicarbonate	p-value
Systolic blood pressure (mmHg)	131 ± 11	130 ± 14	0.71
Diastolic blood pressure (mmHg)	69 ± 8	70 ± 10	0.66
Serum Bicarbonate (mEq/L)	22.6 ± 2.3	25.5 ± 2.2	< 0.001
eGFR (ml/min per 1.73 m²)	40.6 ± 15.6	40.0 ± 15.1	0.65
FGF23 (RU/mL)	150.9 (107.7–267.43)	191.4 (132.6–316.9)	0.048
25-OH vitamin D (ng/mL)	36 ± 13	37 ± 14	0.60
1, 25-OH vitamin D (pg/mL)^c	42 (21–58)	42 (18–57)	0.79
Serum calcium (mg/dL)	9.9 ± 0.5	9.9 ± 0.5	0.39
Serum phosphate (mg/dL)	4.0 ± 0.8	3.9 ± 0.8	0.31
Urine calcium (mg/mg Cr)^b	0.03 (0.02–0.04)	0.01 (0.01–0.05)	0.09
Urine phosphate (mg/mg Cr)^b	0.47 (0.28–0.61)	0.42 (0.32–0.55)	0.84
Urine sodium (mg/mg Cr)^b	2.4 ± 0.7	2.8 ± 1.0	0.07
Fractional excretion of phosphate (%)	18 (14–24)	21 (15–26)	0.22
Fractional excretion of sodium (%)	1.4 (1.1–2.4)	1.6 (1.1–2.2)	0.44

Serum bicarbonate, 25-OH vitamin D, serum calcium, phosphate and urine sodium were expressed as mean ± standard deviation. FGF23, 1,25-OH vitamin D, urine calcium and phosphate, fractional excretion of phosphate and sodium were expressed in median (interquartile range)
Abbreviations: eGFR estimated glomerular filtration rate, 25-OH vitamin D 25-hydroxyvitamin D, 1,25-OH vitamin D 1,25-dihydroxyvitamin D, FGF23 fibroblast growth factor-23
^aValues of variables for “before sodium bicarbonate” were the mean of values between the initial visit and after 2-week placebo
^burine calcium, phosphate and sodium were normalized by dividing urine creatinine. The mean urinary sodium increased from 2.4 ± 0.7 to 2.6 ± 0.9 mg/mg Cr after excluding 2 participants who had their diuretics dose increased prior to the last visit (p = 0.20)
^cOnly 11 participants had 1,25-OHvitamin D level available at before and after 6-week sodium bicarbonate therapy

ISSN: 1471-2369