Effect Of Blood Pressure Variability On Prognosis And Acute Kidney Injury In Critically Ill Patient

BACKGROUND:Changes in blood pressure variability(BPV)may affect tissue and organ perfusion,thereby affecting organ function and patient prognosis.Critically ill patients have complex clinical conditions,unstable hemodynamics,poor organ function,and are more susceptible to damage caused by blood pressure fluctuations.At present,most studies on BPV focus on the surgical population and outpatient hypertensive population,and there are few studies in the critically ill population.Therefore,this study aimed to analyze the characteristics of blood pressure variability in the critically ill patient population,as well as the relationship between BPV and short-term and long-term death.The relationship between the rates,to provide a basis for improving the clinical efficacy of critically ill patients.METHODS:The research subjects were from the MIMIC-Ⅲ database,and a cohort study was conducted by extracting patient data from the database.Blood pressure variability parameters一Coefficient of variation(CV)and Average real variability(ARV)were calculated for each patient based on the recorded values of mean arterial pressure during the first 24 hours of admission to the intensive care unit.The primary endpoint was in-hospital mortality,and secondary endpoints were 28-day mortality and 1-year mortality.Exploring possible nonlinear associations between BPV and mortality with smoothing splines.According to the results of the smooth curve,a two-segment linear regression model is further developed to find out the threshold effect.According to the quartile of ARV,the study population was divided into four groups,which were Q1 group(<5.7mmHg);Q2 group(5.7-7.2mmHg);Q3 group(7.2-9.4mmHg);Q4 group(≥9.4mmHg)),and multivariate logistic regression or Cox proportional hazards models were used to assess the relationship between ARV and mortality.Kaplan-Meier survival analysis was performed on 28-day and 1-year mortality,and subgroup analyses were performed to explore factors affecting their relationship.RESULTS:A total of 12,867 patients were included in the study,of which 1,320 died in hospital,1,399 died within 28 days,and 2,734 died within 1 year.The median age of the study population was 65 years,the median SOFA score was 5,and 61.5%were male.The patients with higher ARV levels were mostly older women and had a history of hypertension,diabetes and other comorbidities.The length of hospital stay,in-hospital mortality,and 28-day and 1-year mortality were higher in patients in the high quantile group than in patients in the middle and low quantiles,and higher in hospitalization,28-day and 1-year mortality in the fourth group than in the other groups(13%,13.9%and 26.4%,respectively).The second group of patients performed better in each of the prognostic indicators among the four groups,with the shortest length of hospital stay and the lowest risk of death.The smoothing spline curve showed that the relationship between BPV and mortality was "U" shaped,and when the ARV was around 7-8 mmHg,the mortality risk of critically ill patients was the lowest.Logistic or Cox regression showed in-hospital mortality(odds ratio:1.44;95%CI,1.21-1.72),28-day mortality(hazard ratio:1.28;95%CI,1.1-1.5),and 1-year mortality(hazard ratio:1.27;95%CI,1.14-1.42)in the highest ARV levels ratewas significantly higher.Survival curves showed that patients with higher ARV levels had a significantly higher risk of death at 28 days and 1 year.The results of the sensitivity analysis showed that the results remained stable regardless of whether the sequential organ failure assessment scores were low or high,indicating that the relationship was still significant in the critically ill population with different disease severities.CONCLUSIONS:Increased blood pressure variability is an independent risk factor for short-term and long-term prognosis in critically ill patients.The relationship between blood pressure variability and mortality was curvilinear,with critically ill patients having the lowest risk of in-hospital death,28-day death,and 1-year death when ARV approached 7-8 mmHg.Objective: The increase or decrease of blood pressure variability(BPV)is a manifestation of the impaired autonomic regulation of blood pressure in the human body,and reflects the dysfunction of the body’s autonomic nervous function;meanwhile,the fluctuation of blood pressure affects the perfusion of tissues and organs,which affects clinical Prognosis.The clinical situation of critically ill patients is complex and the risk of renal injury is high,but there are few previous studies on the relationship between BPV and renal injury in critically ill patients.This study analyzed the risk factors of acute kidney injury(AKI)in critically ill patients during hospitalization,and further explored the relationship between BPV and AKI,in order to provide evidence for organ protection in critically ill patients.Methods: The study was conducted by screening the population in the MIMIC-III database.The blood pressure data of the patients during hospitalization were extracted,and the systolic blood pressure(SBP),diastolic blood pressure(DBP),and mean arterial pressure(MAP)were calculated for each patient on the first day after admission to the ICU.Blood pressure variability parameter-Average real variability(Average real variability,ARV).The primary endpoint was AKI during hospitalization,and the secondary endpoint was moderate-to-severe acute kidney injury during hospitalization(AKI-23).According to the presence or absence of AKI,the patients were divided into AKI group and non-AKI group,and univariate and multivariate Logistic regression models were used to analyze the risk factors of AKI in critically ill patients during hospitalization.In further analyses,smoothing splines were used to explore and statistically test the nonlinear relationship between the variability parameter(as a continuous variable)and outcome.The MAP-ARV(a dichotomous variable with mean as the cutoff point)was included in the multivariate Logistic regression model analysis to explore the relationship between BPV and the occurrence of AKI in critically ill patients during hospitalization.Use the variance inflation factor to test for collinearity between variables.Receiver operating characteristic curve(ROC)was drawn to test the diagnostic value of BPV on outcome.Results: A total of 4654 patients were included in the study,with a median age of 63 years and 60.7% males.AKI occurred in 2571 patients,including 1263 in stage 1,1128 in stage 2,and 180 in stage 3.The population characteristics of AKI in critically ill patients are advanced age,male,emergency admission,higher SOFA score and SAPS-II score on the first day of ICU admission,and a higher probability of hypertension,diabetes,and sepsis.Compared with the non-AKI group,MAP-ARV and SBP-ARV were higher in the AKI group,but there was no significant difference in DBP-ARV between the groups.Patients in the AKI group had higher proportions of in-hospital death,28-day deatii,and 1-year death than those in the non-AKI group.Age,gender,emergency admission,SOFA score,ventilation therapy,sepsis,coronary heart disease,and congestive heart failure and MAP-ARV were independent risk factors for acute kidney injury in critically ill patients.Curve fitting showed no obvious nonlinear relationship between BPV and AKI during hospitalization.Inclusion of BPV as a dichotomous variable into a multivariate logistic regression equation and after adjustaent for oAer covariates showed higher than mean MAP-ARV was associated with an increased risk of developing AKI(OR,1.17;95% Cl,1.02-1.33;P = 0.021)and AKI-23(OR,1.23;95% CI51.07-1.42;P = 0.004).The results of subgroup analysis showed ihat this relationship was stable in patients with diflFerent ages,diflFerent SOFA scores,different types of admission,with or without hypertension,and with or without diabetes.However,ROC showed that MAP-ARV has limited diagnostic value for AKI in critically ill patients during hospitalization.Conclusions: Independent risk factors for acute kidney injury in critically ill patients include advanced age,male sex,emergency hospital admission,high SOFA score,ventilation therapy,sepsis,coronary heart disease,congestive heart failure,and MAP-ARV.As a categorical variable,higher_than_average MAP-ARV was associated with an increased risk of AKI during hospitalization in critically ill patients and was an independent risk factor for AKI during hospitalization.However,the diagnostic value of MAP-ARV for AKI in critically ill patients during hospitalization is limited.