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Table 4 Logistic regression analysis of factors associated with severe abdominal aortic calcification

From: A low fractional excretion of Phosphate/Fgf23 ratio is associated with severe abdominal Aortic calcification in stage 3 and 4 kidney disease patients

Model 1     Model 2   
Variable Exp(B) 95% CI p Exp(B) 95% CI p
Intercept 0.003 0.000; 0.022 <.001 0.005 0.000; 0.050 <.001
Male sex 4.218 1.403; 14.207 0.014 4.167 1.050; 20.178 0.05
Age (y) - 50 1.111 1.047; 1.194 0.002 1.083 1.011; 1.177 0.037
CKD Stage 4 vs. 3 3.290 1.068; 10.773 0.041 N/A N/A N/A
Carotid plaque 6.131 1.605; 27.983 0.011 17.387 2.750;175.88 0.006
Cutoff point       
((FEP/FGF23) < 1/3.9) 3.915 1.346; 12.364 0.015 6.873 1.703; 35.999 0.011
  1. Exp (B) for the intercept measures the estimated odds of KI > 5 for the reference or zero values of the explanatory variables in the model. Exp (B) of the predictor measures the odds ratio (B) associated to the variable category or 1 unit change depending of the nature of the variable. The table provides with Exp (B) and 95% confidence intervals (CI) for variables with a statistically significant (p < 0.05) contribution to explain the magnitude of abdominal aortic calcification (AAC) in a multivariate logistic regression model comparing KI > 5 vs. KI = 0 for all patients (Model 1), or among patients with an estimated GFR below 30 ml/min (Model 2). The ratio FEP/FGF23 was introduced as a binary variable with a cutoff point of (FEP/FGF23) < (1/3.9) (or equivalently, log2(FEP/FGF23) < log2(1/3.9)). The ROC curve in Figure 2 shows the high sensitivity and specificity of the logistic regression analysis in Model 1 (Area under the ROC curve = 0.89 and good model calibration, as measured by Hosmer-Lemenshow goodness-of-fit test p = 0.95). For Model 2, the area under the ROC curve = 0.899 and HL test p = 0.55.