Objective:To explore the predictive value of very low frequency (VLF) for the efficacy of vitamin D treatment in children with postural orthostatic tachycardia syndrome (POTS).Methods:A retrospective case-control study was conducted. A total of 65 POTS children from the Department of Pediatrics of the Second Hospital of Lanzhou University from November 2023 to May 2024 were selected as the research subjects, while 102 healthy children from the same period were selected as the control group. The 25 (OH) D levels between POTS children and healthy children were compared. The frequency of eight main symptoms, including palpitations, headache, cold sweat, blurred vision, chest tightness, dizziness, fainting, and digestive discomfort in the POTS group were analyzed, the symptom scores of the orthostatic intolerance were calculated, and the parameters related to short-range heart rate variability (HRV) during the upright test, head-up tilt test (HUTT) were collected. The correlation between 25 (OH) D levels and symptom scores of orthostatic intolerance symptoms and HRV parameters in children with POTS were analyzed by Pearson correlation analysis. The total symptom scores of children with POTS were compared for 3 months before treatment and 2 months after treatment with vitamin D 800 U/d. The difference in score before and after treatment was ≥2 as responsive group, and the score difference before and after treatment was <2 as non-responsive group. The demographic characteristics including age, gender, height, weight, body mass index, as well as HRV parameters such as the standard deviation of nn intervals (SDNN), the standard deviation of the average NN intervals (SDANN), the root mean square of successive differences (rMSSD), low-frequency (LF), high-frequency (HF), very-low-frequency (VLF) were compared between the responsive group and non-responsive group. Multivariate Logistic regression was analyzed to screen independent influencing factors of vitamin D treatment efficacy for POTS. The marker molecules related to the efficacy of vitamin D treatment in children with POTS were analyzed through receiver operating characteristic (ROC) curve.Results:A total of 167 children were included in this study. There were 65 children in the POTS group, 38 males and 27 females, with the age of (10.6±2.2) years. There were 102 healthy children in the control group, 53 males and 49 females, with the age of (11.2±1.8) years.There was no statistically significant difference in gender and age between the two groups (both P>0.05). The serum 25 (OH) D level in children in the POTS group was (37±18)nmol/L, lower than that in the control group (61±17)nmol/L ( P<0.05).Pearson correlation analysis showed that serum 25(OH)D was positively correlated with VLF, SDNN and HF ( r=0.43, 0.65, 0.36, respectively, all P<0.05). Among the POTS children, there were 48 cases in responsive group and 17 cases in non-responsive group. Univariate analysis revealed that responsive group exhibited significantly lower values in age, SDNN, SDANN, and VLF compared to the non-responsive group (all P<0.05). Multivariate Logistic regression analysis showed that age ( OR=1.47, 95% CI 1.08-2.01), SDNN ( OR=1.01, 95% CI 1.00-1.22) and VLF ( OR=1.01, 95% CI 1.00-1.15) were independent influencing factors in the effect of vitamin D in POTS children (all P<0.05). ROC curve analysis showed that the area under the curve of VLF predicting response to vitamin D treatment for POTS was 0.72 (95% CI 0.58-0.85, P=0.008). When the cutoff value was 1 272 ms 2, the sensitivity and specificity were both 70%. Conclusion:VLF may help predict the efficacy of vitamin D treatment in children with POTS.

Objective:To explore the predictive value of very low frequency (VLF) for the efficacy of vitamin D treatment in children with postural orthostatic tachycardia syndrome (POTS).Methods:A retrospective case-control study was conducted. A total of 65 POTS children from the Department of Pediatrics of the Second Hospital of Lanzhou University from November 2023 to May 2024 were selected as the research subjects, while 102 healthy children from the same period were selected as the control group. The 25 (OH) D levels between POTS children and healthy children were compared. The frequency of eight main symptoms, including palpitations, headache, cold sweat, blurred vision, chest tightness, dizziness, fainting, and digestive discomfort in the POTS group were analyzed, the symptom scores of the orthostatic intolerance were calculated, and the parameters related to short-range heart rate variability (HRV) during the upright test, head-up tilt test (HUTT) were collected. The correlation between 25 (OH) D levels and symptom scores of orthostatic intolerance symptoms and HRV parameters in children with POTS were analyzed by Pearson correlation analysis. The total symptom scores of children with POTS were compared for 3 months before treatment and 2 months after treatment with vitamin D 800 U/d. The difference in score before and after treatment was ≥2 as responsive group, and the score difference before and after treatment was <2 as non-responsive group. The demographic characteristics including age, gender, height, weight, body mass index, as well as HRV parameters such as the standard deviation of nn intervals (SDNN), the standard deviation of the average NN intervals (SDANN), the root mean square of successive differences (rMSSD), low-frequency (LF), high-frequency (HF), very-low-frequency (VLF) were compared between the responsive group and non-responsive group. Multivariate Logistic regression was analyzed to screen independent influencing factors of vitamin D treatment efficacy for POTS. The marker molecules related to the efficacy of vitamin D treatment in children with POTS were analyzed through receiver operating characteristic (ROC) curve.Results:A total of 167 children were included in this study. There were 65 children in the POTS group, 38 males and 27 females, with the age of (10.6±2.2) years. There were 102 healthy children in the control group, 53 males and 49 females, with the age of (11.2±1.8) years.There was no statistically significant difference in gender and age between the two groups (both P>0.05). The serum 25 (OH) D level in children in the POTS group was (37±18)nmol/L, lower than that in the control group (61±17)nmol/L ( P<0.05).Pearson correlation analysis showed that serum 25(OH)D was positively correlated with VLF, SDNN and HF ( r=0.43, 0.65, 0.36, respectively, all P<0.05). Among the POTS children, there were 48 cases in responsive group and 17 cases in non-responsive group. Univariate analysis revealed that responsive group exhibited significantly lower values in age, SDNN, SDANN, and VLF compared to the non-responsive group (all P<0.05). Multivariate Logistic regression analysis showed that age ( OR=1.47, 95% CI 1.08-2.01), SDNN ( OR=1.01, 95% CI 1.00-1.22) and VLF ( OR=1.01, 95% CI 1.00-1.15) were independent influencing factors in the effect of vitamin D in POTS children (all P<0.05). ROC curve analysis showed that the area under the curve of VLF predicting response to vitamin D treatment for POTS was 0.72 (95% CI 0.58-0.85, P=0.008). When the cutoff value was 1 272 ms 2, the sensitivity and specificity were both 70%. Conclusion:VLF may help predict the efficacy of vitamin D treatment in children with POTS.

Objective::Older patients with comorbidity, such as coronary heart disease (CHD) and malignant gastrointestinal tumors, are at a high risk of bleeding events. However, risk prediction models based on risk factor assessment remain unclear. This study aimed to establish an individualized bleeding risk assessment system based on the analysis of 10-year inpatient clinical big data.Methods::Total clinical data of 56,819 patients with CHD and 25,988 patients with malignant digestive tract tumors (admitted from January 2008 to December 2017) were retrospectively collected at the First and Second Medical Centers of Chinese People’s Liberation Army General Hospital. Among them, 1307 patients with CHD and malignant digestive tract tumors were screened as the derivation cohort. The dependent variable was the occurrence of major clinical bleeding events. Baseline statistics and hypothesis tests of differences were performed for independent variables according to the occurrence of bleeding. Decision Tree, eXtreme Gradient Boosting (XGBoost), logistic regression, and random forest models were used for comparison. The accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC-ROC) were applied as the criteria for evaluating and verifying model performance. To evaluate this developed model, another cohort comprising 454 patients (admitted from January 2018 to December 2019) was prospectively enrolled as the validation cohort based on the same inclusion and exclusion criteria.Results::Among the 64 variables with <50% missing values, the recursive feature elimination method with a random forest model was used to screen the selected variables. The highest accuracy was obtained following the selection of 10 scalars, and the final model was constructed accordingly. XGBoost demonstrated the best performance comprehensively. The AUC-ROC of this model was 0.981, with an accuracy, sensitivity, and specificity of 0.939, 0.950, and 0.927, respectively. In the validation cohort, the AUC-ROC, accuracy, sensitivity, and specificity of the XGBoost model were 0.702, 0.718, 0.636, and 0.725, respectively. The rate of major bleeding events has a positive correlation with the bleeding risk score quintiles. To allow for convenient clinical application, a smartphone application was developed for easy access and calculation (http://fir.master-wx.com/sghr).Conclusion::We successfully established a risk model and score for predicting bleeding events in older patients with comorbidity, such as CHD and gastrointestinal cancer.

Objective::Older patients with comorbidity, such as coronary heart disease (CHD) and malignant gastrointestinal tumors, are at a high risk of bleeding events. However, risk prediction models based on risk factor assessment remain unclear. This study aimed to establish an individualized bleeding risk assessment system based on the analysis of 10-year inpatient clinical big data.Methods::Total clinical data of 56,819 patients with CHD and 25,988 patients with malignant digestive tract tumors (admitted from January 2008 to December 2017) were retrospectively collected at the First and Second Medical Centers of Chinese People’s Liberation Army General Hospital. Among them, 1307 patients with CHD and malignant digestive tract tumors were screened as the derivation cohort. The dependent variable was the occurrence of major clinical bleeding events. Baseline statistics and hypothesis tests of differences were performed for independent variables according to the occurrence of bleeding. Decision Tree, eXtreme Gradient Boosting (XGBoost), logistic regression, and random forest models were used for comparison. The accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC-ROC) were applied as the criteria for evaluating and verifying model performance. To evaluate this developed model, another cohort comprising 454 patients (admitted from January 2018 to December 2019) was prospectively enrolled as the validation cohort based on the same inclusion and exclusion criteria.Results::Among the 64 variables with <50% missing values, the recursive feature elimination method with a random forest model was used to screen the selected variables. The highest accuracy was obtained following the selection of 10 scalars, and the final model was constructed accordingly. XGBoost demonstrated the best performance comprehensively. The AUC-ROC of this model was 0.981, with an accuracy, sensitivity, and specificity of 0.939, 0.950, and 0.927, respectively. In the validation cohort, the AUC-ROC, accuracy, sensitivity, and specificity of the XGBoost model were 0.702, 0.718, 0.636, and 0.725, respectively. The rate of major bleeding events has a positive correlation with the bleeding risk score quintiles. To allow for convenient clinical application, a smartphone application was developed for easy access and calculation (http://fir.master-wx.com/sghr).Conclusion::We successfully established a risk model and score for predicting bleeding events in older patients with comorbidity, such as CHD and gastrointestinal cancer.