Analysis Of Influencing Factors Of Ambulatory Blood Pressure In Adolescents, Comparison Of Diagnostic Criteria And Development Of A Blood Pressure Prediction Mode

Part 1:Seasonal variation of ambulatory blood pressure in adolescents from North ChinaBackground and objectiveBlood pressure(BP)exhibits seasonal variation with lower levels at higher temperatures and vice versa.This phenomenon is observed in both sexes and all age groups.So far,only a few researches have investigated this condition in adolescents and none of them were based on Chinese population or ever applied ambulatory blood pressure monitoring(ABPM).Therefore,we carried out the first study which used ABPM to record seasonal variation of blood pressure in Chinese hypertensive adolescents.MethodsFrom March 2018 to February 2019,649 ABPM reports from hypertensive adolescents between 13 to 17 years who were referred to wear an ABPM device in Beijing and Baoding were extracted.Basic demographic information including age,gender,height and weight was extracted from the database of ABPM reports.Seasonal change in ambulatory BP value,dipping status and prevalence of different BP phenotype were analyzed and compared.Each season was defined as follows:summer ranged from 1 June to 31 August;winter ranged from 1 December to the last day of next year’s February;spring ranged from 1 March to 31 May and autumn ranged from 1 September to 31 November.Average temperature of each month during the studied period was recorded.Due to the similar temperature,spring and autumn were merged into one group named middle season in present study.ResultsMean age of participants was 14.9±1.5 years and 65.8%of them were boy.75.3%of participants met the criteria of overweight or obesity.Compared with other seasons,adolescents in winter group had higher level of BMI.From summer to winter,average 24-hour,day-time and night-time BP showed significant rise,which was 9.8/2.8 mm Hg,9.8/3.0 mm Hg and 10.9/3.4 mm Hg respectively.After adjusted for age,sex,BMI and office BP,winter was still strongly related with increasing ambulatory blood pressure in adolescents(P<0.001).However,this seasonal effect on BP was not dependent on obesity degree.In addition,higher prevalence of non-dippers existed in winter(winter vs.summer,70.3%vs.57.4%,P=0.009,winter vs.middle,70.3%vs.51.6%,P<0.001).On the contrary,white coat hypertension was more frequent in warmer seasons(summer:18.4%,middle:14.4%,winter:4.4%,P<0.001).ConclusionsHypertensive adolescents showed evident seasonal change in their ABPM results,which was featured by elevated BP level and more frequent abnormal dipping patterns in winter.On the contrary,higher prevalence of white coat hypertension was found in warmer seasons.Physicians should take seasonal variation into consideration when managing adolescent hypertension.Part 2:Sex difference in nocturnal blood pressure dipping in adolescents with varying degrees of adiposityBackground and objectiveFor adolescents,abnormal dipping patterns in blood pressure(BP)are associated with early-onset organ damage and higher risk of cardiovascular disorders in adulthood.Obesity is one of the leading reasons for abnormal BP dipping in young people.However,it is unknown whether the severity of obesity is associated with BP dipping status and whether this association is sex-dependent.Methods499 participants between 12 to 17 years old with overweight or obesity underwent ambulatory blood pressure monitoring(ABPM)between April 2018 and February 2019 in Beijing and Baoding were included.Participants were grouped by body mass index(BMI)into overweight(BMI 85th-95th percentile),obese(BMI≥95th percentile)and extreme obese(BMI≥120%of 95th percentile or≥35 kg/m2)groups.Non-dipping status was defined as less than 10%reduction in BP from day to night.The interaction effect between sex and obesity degree was analyzed and the prevalence of non-dipper in different obesity level was compared.Results326 boys and 173 girls were included,of whom 130 were overweight,189 were obese,and 180 were extreme obese.Compared with their overweight and obese counterparts,girls who were extreme obese demonstrated a higher prevalence of non-dipping status in BP(72.4%vs.48.8%,P=0.017,72.4%vs.50.0%,P=0.009).This finding was further confirmed by multivariate logistic regression analysis.However,boys showed no significant differences in BP dipping status between obesity categories(61.8%vs.61.7%vs.58.2%,P=0.808).In addition,as obesity severity went up,a more evident increase in night-time SBP was observed in girls than in boys(P=0.014).ConclusionsThe relationship between obesity severity and BP dipping patterns was sex-dependent.For overweight and obese adolescent girls,increasing severity of obesity was associated with a higher prevalence of non-dipping status in blood pressure.However,this relationship was not detected in boys.These findings added to the accumulating evidence regarding sex-related differences in pediatric cardiometabolic disorders and suggested that sex-specific treatment might be encouraged.Part 3:Comparison of different criteria for the diagnosis of hypertension in adolescents:a study from Chinese cohortBackground and objectiveFor years,sex-and age-specific or sex-and height-specific percentile norms have been recommended to diagnosis hypertension in adolescents.However,due to its complexity,determining BP according to percentile usually caused inconvenience in clinical use.In the updated guidelines of ambulatory blood pressure monitoring(ABPM)in children and adolescents published by American Heart Association(AHA)in 2022,adult BP norms are applied on adolescents over 13 years for the diagnosis for both clinic and ambulatory hypertension.To compare these two different criteria in detecting hypertension in Chinese adolescents,present study was carried out.Study designABPM reports from adolescents age 13-17 from 2018-2019 were analyzed.The percentage of clinic and ambulatory hypertension based on different criteria was compared using the McNemar’s test.When using percentile,both clinic and ambulatory hypertension was defined as BP≥sex-and age-specific 95th percentile.Under the AHA 2022 criteria,clinic hypertension was defined as office BP≥130/80 mm Hg while ambulatory hypertension was defined as overall BP≥125/75mmHg,wake BP≥130/80 mm Hg or sleep BP≥110/65mmHg.BP phenotype including white coat hypertension(WCH),masked hypertension(MH)and sustained ambulatory hypertension(SHT)was also reclassified using different criteria.ResultsOf 416 adolescents,364(87.5%)had ambulatory hypertension based on AHA 2022 criteria versus 314(75.5%)based on 95th percentile and such difference was significant(P<0.001).However,no significant difference was found when referring to the diagnosis of clinical hypertension(93.0%vs 91.8%,P=0.227).A higher prevalence of WCH was defined by 95th percentile(21.4%)compared with AHA2022 criteria(10.8%).On the contrary,less frequent of sustained ambulatory hypertension was defined by 95th percentile(70.4%)compared with AHA 2022 criteria(82.2%).Such differences were observed in both boys and girls.ConclusionsCompared with sex-and age-specific 95th percentile,AHA 2022 criteria had similar performance in diagnosing clinical hypertension while defined a higher prevalence of ambulatory hypertension in Chinese adolescents.As a result,less frequent of WCH as well as higher percentage of sustained ambulatory hypertension was reclassified using AHA 2022 criteria.Further studies are welcomed to find out the clinical outcome of such difference.Part 4:Development and prospect of a newly designed predicting model in blood pressureDue to the development of information technology and computer science,artificial intelligence(AI)has been noticed in the field of medicine.By applying methods like machine learning and using big data,AI could be "trained" to build a blood pressure predicting model which helps to identify people at higher risk of developing hypertension.Besides,when combined with wearable monitoring devices in continuous blood pressure measurement,this predictive model can prove real-time calibration.The following paper will introduce a newly design AI-enhanced blood pressure predicting model(application number:CN202211423104.4)and its application prospects.