Assessing the relationship between short-term blood pressure variability and glycation profile in young and middle-aged nondiabetic hypertensive individuals

Figures

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  FIGURE 1. Comparison of blood pressure variability between patients with glycated hemoglobin levels below (blue) and above (green) 5.2%. (a) SD indices; (b) CV indices; (c) ARV indices; (d) nighttime BPV dipping. Results marked with ∗∗ reached a P value of less than 0.05. The numerical values of all indices are shown in Supplementary Table 1. %, percentage; 24-hDBP, 24-h DBP; 24-hSBP, 24-h SBP; ARV, average real variability; BP, blood pressure; BPV, blood pressure variability; CV, coefficient of variation; DBP, diastolic BP; dDBP, daytime DBP; dSBP, daytime SBP; HbA1c, glycated hemoglobin; nDBP, nighttime DBP; nSBP, nighttime SBP; SBP, systolic BP; SD, standard deviation.

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  FIGURE 2. Overall linear correlation analysis for blood pressure variability indices and glycated hemoglobin levels. (a) Correlation between HbA1c levels and nighttime SD indices; (b) correlation between HbA1c levels and nighttime CV indices; (c) correlation between HbA1c levels and nighttime ARV indices. Equations: nDBP-SD = −4.69 + 0.88∗HbA1c; nSBP-SD = −5.1 + 0.96∗HbA1c; nDBP-SD dipping= 5.38 + (−1.01)∗HbA1c; nSBP-SD dipping= 4.31 + (−0.81)∗HbA1c; nDBP-CV= −5.41 + 1.02∗HbA1; nSBP-CV= −4.74 + 0.89∗HbA1c; nDBP-CV dipping= 4.75 + (−0.89)∗HbA1c; nSBP-CV dipping= 3.99 + (−0.75)∗HbA1c; nDBP-ARV= −3.57 + 0.67∗HbA1c; nSBP-ARV = −1.86 + 0.35∗HbA1c; nDBP-ARV dipping = 4.88 + (−0.92)∗HbA1c; nSBP-ARV dipping = 0.8 + (−0.15)∗HbA1c. Results marked with ∗∗ reached a P value less than 0.05. The complete results of the linear correlation analysis are presented in Supplementary Table 2. ARV, average real variability; BP, blood pressure; CV, coefficient of variation; HbA1c, glycated hemoglobin; nDBP, nighttime DBP; nSBP, nighttime SBP; SD, standard deviation.

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  FIGURE 3. Principal component analysis to build an overall combined blood pressure variability index as a composite marker of the individual blood pressure variability parameters that achieved relevant results. (a) Ecree plot showing the PCs and their eigenvalues; (b) bar chart depicting the explained variance of the PCs; (c) scatterplot highlighting the most relevant PCs in relation to HbA1c levels; (d) heat map displaying the individual indices loadings for each PC. Among the components obtained from the PCA, only the first two PCs exhibited eigenvalues greater than 1. Together, these two components account for approximately 80% of the total variance (PC1: 65%, PC2: 14%) (a and b). When considering HbA1c levels categorized by the predefined cutoff of 5.2%, PC1 emerged as the primary differentiator between the two groups (c). This finding suggests that PC1 captures the majority of the variability associated with distinctions in HbA1c levels. Furthermore, the loadings of PC1 revealed balanced contributions from the original variables, indicating that this component proportionally summarizes their variability without disproportionately favoring any specific variable (d). This balance…

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  FIGURE 4. Receiver-operating characteristics curve for glycated hemoglobin levels (cutoff point 5.2%) comparing an optimal basal model (age, sex and physical activity) with (a) the overall combined BPV index and (b) the combined SD, CV, and ARV indices. Basal model: AUC = 0.754, SE = 0.042, P < 0.001, 95% CI (0.673–0.836), sensibility = 0.66, 1-specificity = 0.21; overall combined BPV index: AUC = 0.800, SE = 0.037, P < 0.001, 95% CI (0.727–0.873), sensibility = 0.73, 1 − specificity = 0.21; SD combined index: AUC = 0.807, SE = 0.037, P < 0.001, 95% CI (0.735–0.879), sensibility = 0.73, 1 − specificity = 0.21; CV combined index: AUC = 0.807, SE = 0.037, P < 0.001, 95% CI (0.734–0.879), sensibility = 0.71, 1 − specificity = 0.21; ARV combined index: AUC = 0.773, SE = 0.041, P < 0.001, 95% CI (0.693–0.853), sensibility = 0.69, 1 − specificity = 0.27). ARV, average real variability; AUC, area under the curve; BP, blood pressure; BPV, blood pressure variability; CV, coefficient of variation; HbA1c, glycated hemoglobin; SD, standard deviation; SE, standard error.