Repeatability Of Circadian Rhythms In Elderly Essential Hypertensives And Its Relationship With Cognitive Function

Part I：Repeatability Of Ambulatory Blood Pressure Monitoring InElderly Patients With Essential HypertensionObjective ABPM technique has been widely used at home and abroad clinically.However，repeatability of ABPM parameters are not consistent in some researches, whichcaused many scholars had questioned whether it is worthwhile to further promotion. In thisstudy，we analyze the short-term repeatability of ABPM in elderly hypertensive patientsto assess its significance in clinical and experimental research.Methods139elderly essential hypertensive patients (106males and33females,aged84.04±4.77years) of Shanghai Sixth People’s Hospital geriatric inpatients werechosen to undergo24h ABPM twice within4weeks，we analyze the consistency ofcontinuous variables and categorical variables with Bland-Altmant plot and kappa testrespectively.Results （1）The mean BP value of24h、daytime、nighttime were corresponded wellbetween the first and second ABPM recordings as showed by Bland-Altman plots. Itsrepeatability coefficient（%of Near Maximal Variability, MV%）was2%、2.4%，2.1%、2.5%、2.5%、3.0%respectively.（2）84.2%(117/139) of patients(18�'DD,99ND�'ND)confirmed their initial profile，15.8%（22/139）switched from dipper tonon-dipper ((D�'ND) or the opposite(ND�'D)，kappa=0.523（P＜0.01). Bland-Altmanplot showed repeatability of nSBP/dSBP was acceptable as continuous variables, andMV%was37.5%. Conclusion The short-term repeatablity of average blood pressure is overallsatisfactory. Diurnal blood rhythm has an acceptable repeatablity no matter whether it isanalysed as continuous or categorical variable. The fluctuation of nocturnal dipping may berelated to mean daytime blood pressure wave. Given the repeatability of ABPM affected bymany factors, circadian rhythm by ABPM once a time is not reliable,we should repeatedABPM to detect abnormal blood pressure patterns earlier, which will be clinicallysignificant for prognosis assessment of target organ damage.Part II: Relationship Between Repeated Circadian Rhythm WithCognitive Function In The ElderlyObjective There are differences in previous research findings on the relationshipbetween senile cognitive impairment and abnormal circadian rhythm. Definiting nocturnaldipping status on the basis of a single ABPM is questionable. It will be more reliable torepeat ABPM to classify circadian pattern and research the relationship between thedipping status with cognition，which counts for slowing down the progression of cognitiveimpairment preclinically.Methods Patients were classified into three groups: reproducible dippers (group D);reproducible non-dippers (group ND); variable-dippers (group VD). We selected MMSEand MOCA scores to assess cognitive function, and compared its differences among threegroups，and analyzed its relationship with48h blood pressure circadian rhythm（48hnSBP/dSBP）.Results MMSE score of group ND was significantly lower than group D（26.00(24.00-28.00)＜28.00(26.75-29.00），P＜0.01）and group VD was also lower thangroup D (26.00（25.75-28.00）＜28.00(26.75-29.00），P＜0.01).There was no significantstatistical difference between group ND and group VD.Similarly，MOCA score of groupND （21.35±4.02） and group VD （20.65±2.91） were also lower than group D（23.50±4.62）.48h nSBP/dSBP was negatively connected with the MMSE score（r=﹣0.231，P=0.006）and has association with MMSE scores independently（β=﹣0.227）. Therewas no significant association between the MOCA score and48h nSBP/dSBP.Conclusion Reproducible non-dipper pattern and unstable dipping pattern has association with cognitive impairment in elderly hypertensive patients，and the circadianrhythm of blood pressure was associated with cognitive function independently.