Association of High Calcitriol Serum Levels and Its Hydroxylation Efficiency Ratio with Disease Risk in SLE Patients with Vitamin D Deficiency

Table 1

Clinical characteristics by clinical activity in SLE patients.

Variable	Total	SLE patients		value
		Clinical activity (Mex-)	Clinical inactivity (Mex-)
Age (years)^a	37 (20–58)	36 (21–56)	37 (20–60)	0.65
Disease evolution time (years)				0.44
<5 years^b	44 (63/143)	48 (30/63)	41 (33/80)
>5 years^b	56 (80/143)	52 (33/63)	59 (47/80)
SLICC ACR-DI^a	0 (0–4)	1 (0–4)	0 (0–2)	<0.001
Damage ()^b	42 (55/130)	64 (36/56)	26 (19/74)	<0.001
Renal activity ^b	30 (26/87)	45 (15/33)	20 (11/54)	0.01
Renal insufficiency ^b	14 (12/83)	21 (7/34)	10 (5/49)	0.18
Serum variables
ANAs (+)^b	81 (100/123)	81 (44/54)	81 (56/69)	0.96
Anti-dsDNA (+)^b	42 (59/139)	70 (16/23)	53 (20/38)	0.19
C3 (mg/dL)^a	114 (55.3–150)	101 (1.17–123)	115 (55.3–156)	0.20
C4 (mg/dL)^c				0.19
Calcidiol (ng/mL)^a	21.9 (5.1–40.4)	21.2 (3.26–36.6)	22.4 (12.0–40.4)	0.14
Calcidiol reference values % ()				0.34
Sufficiency (≥30 ng/mL)^b	18 (26/144)	13 (8/62)	22 (18/82)
Insufficiency (≥20 to <30 ng/mL)^b	38 (55/144)	39 (24/62)	38 (31/82)
Deficiency: (<20 ng/mL)^b	44 (63/144)	48 (30/62)	40 (33/82)
Calcitriol (pg/mL)^a	46.9 (22.1–101)	48.5 (21.7–117)	46.2 (22.1–95.2)	0.32
Calcitriol tertiles % ()				0.26
(≥48.7 to 157.3 pg/mL)^b	43 (61/142)	50 (30/60)	38 (31/82)
(≥33.6 to <48.7 pg/mL)^b	37 (53/142)	30 (18/60)	43 (35/82)
(0.33 to <33.6 pg/mL)^b	20 (28/142)	20 (12/60)	19 (16/82)
Calcitriol/calcidiol ratio (pg/ng)^a	2.15 (0.73–9.13)	2.78 (0.84–18)	1.92 (0.71–6.43)	0.02
Calcitriol/calcidiol ratio tertiles % ()				0.58
(≥2.23 to 23.6 pg/ng)^b	47 (67/141)	52 (31/60)	44 (36/81)
(≥1.36 to ≤2.23 pg/ng)^b	31 (44/141)	27 (16/60)	35 (28/81)
(0.01 to <1.36 pg/ng)^b	21 (30/141)	21 (13/60)	21 (17/81)
Serum calcium (mg/dL)^c				0.01

^aData provided in medians (percentile: –), Mann–Whitney test. ^bData provided in percentages (/total patients), test. ^cData provided in , Student -test. The bold numbers indicate the variables with significant differences. SLICC: Systemic Lupus International Collaborating Clinics, American College of Rheumatology Damage Index; Mex-SLEDAI: Mexican Systemic Lupus Erythematosus Disease Activity Index; ANAs: antinuclear antibodies; Anti-dsDNA: anti-double-stranded DNA antibodies; C3 and C4: complement.