Table 3.
Association between SOx and major artery calcification volume by linear regression analysis.
| Univariable analysis | Multivariable analysis | Variable selection (AIC) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| β | 95 %CI | P | β | 95% CI | P | β | 95% CI | P | |
| SOx (µmol/L) | 0.04 | 0.01 to 0.07 | 0.022 | 0.02 | − 0.02 to 0.06 | 0.264 | 0.03 | 0.00–0.06 | 0.084 |
| Age (years) | 0.31 | 0.09 to 0.54 | 0.007 | 0.29 | 0.03 to 0.55 | 0.027 | 0.26 | 0.05–0.47 | 0.018 |
| Male | 4.73 | –1.03 to 10.50 | 0.105 | 1.98 | − 4.35 to 8.31 | 0.531 | |||
| HD duration (months) | 0.00 | –0.03 to 0.03 | 0.972 | ||||||
| Diabetes mellitus | 1.66 | –4.17 to 7.49 | 0.570 | ||||||
| BMI (kg/m2) | –0.29 | –1.12 to 0.53 | 0.478 | ||||||
| Ankle-brachial index | 6.49 | –15.71 to 28.70 | 0.559 | ||||||
| aCa (mg/dL) | 3.65 | –1.75 to 9.05 | 0.180 | 3.26 | − 2.35 to 8.87 | 0.248 | |||
| Phosphate (mg/dL) | –0.26 | –3.47 to 2.95 | 0.871 | ||||||
| iPTH (pg/dL) | –0.01 | –0.03 to 0.02 | 0.545 | ||||||
| ALP (U/mL) | –0.01 | –0.04 to 0.01 | 0.352 | ||||||
| Magnesium (mg/dL) | –2.14 | –11.94 to 7.67 | 0.663 | ||||||
| Triglyceride (mg/dL) | 0.00 | –0.04 to 0.04 | 0.980 | ||||||
| LDL-C (mg/dL) | –0.01 | –0.14 to 0.11 | 0.856 | ||||||
| HDL-C (mg/dL) | –0.16 | –0.34 to 0.01 | 0.071 | − 0.11 | − 0.30 to 0.07 | 0.228 | |||
| Uric acid (mg/dL) | 0.72 | –2.66 to 4.10 | 0.670 | ||||||
| β2MG (µg/L) | 0.74 | 0.17 to 1.30 | 0.013 | 0.42 | − 0.23 to 1.06 | 0.200 | 0.55 | 0.00–1.09 | 0.048 |
| BUN (mg/dL) | –0.16 | –0.44 to 0.12 | 0.267 | ||||||
| Hemoglobin (g/dL) | –0.07 | –3.55 to 3.40 | 0.966 | ||||||
| Serum albumin (g/dL) | –7.36 | –17.45 to 2.73 | 0.149 | 3.95 | − 7.57 to 15.47 | 0.492 | |||
| CaCO3 intake | 6.53 | –1.34 to 14.39 | 0.102 | − 0.33 | − 8.97 to 8.30 | 0.939 | |||
| Vitamin D medication | 2.20 | –3.62 to 8.01 | 0.451 | ||||||
| Statin intake | –5.13 | –13.08 to 2.82 | 0.201 | ||||||
A linear regression analysis was performed for the association between SOx and major artery calcification volume. The explanatory variable was SOx, and the covariates were factors that are reported to be associated with vascular calcification8,25,32,33 or CVD29,34–36. A univariable analysis was performed first, and factors with a two-tailed P value < 0.2 were used for a multivariable analysis. For variable selection, we used Akaike’s information criteria with stepwise backward elimination. A two-tailed P value of < 0.05 was considered to indicate statistical significance.
aCa albumin-adjusted calcium, AIC Akaike’s information criteria, ALP alkaline phosphatase, β2MG beta-2 microglobulin, BUN blood urea nitrogen, BMI body mass index, CaCO3 calcium carbonate, CI confidence interval, HD hemodialysis, HDL-C high-density lipoprotein cholesterol, iPTH intact parathyroid hormone, LDL-C low-density lipoprotein cholesterol, SOx serum oxalate concentration.