Body mass index and risk of post-induction hypotension in older adults undergoing non-cardiac surgery: a retrospective cohort study

Figures

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  Fig. 1. Flow Diagram of Patient Selection for the Final Study Cohort Flowchart depicting the selection process of patients aged ≥ 60 years from the Electronic Anaesthesia Medical Record System (EAMRS) database between January 2013 and December 2022. A total of 95,726 surgical records were initially screened. After exclusion of cases with missing or extreme data (n = 10,281), and those not meeting inclusion criteria (non-general anaesthesia, emergency or cardiac surgery, baseline hypotension; n = 14,958), 70,487 patients were included in the final analysis. Abbreviations: PUMCH Peking Union Medical College Hospital, EAMRS Electronic Anaesthesia Medical Record System, BMI Body mass index, SBP Systolic blood pressure, HIS Hospital information system, ASA American Society of Anesthesiologists

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  Fig. 2. Association Between Body Mass Index and Primary and Secondary Outcomes Restricted cubic spline (RCS) models illustrating the association between body mass index (BMI) and four perioperative outcomes: (A) Post-induction hypotension (PIH), (B) Intensive care unit (ICU) admission, (C) Length of hospital stay, and (D) In-hospital mortality. The reference point was set at the median BMI of 24.2 kg/m². The solid red lines indicate adjusted estimates, and shaded areas represent 95% confidence intervals (CIs). Vertical dashed lines indicate the WHO-recommended BMI thresholds for the Chinese population: 18.5, 24.0, and 28.0 kg/m². Logistic regression was used for PIH, ICU admission, and in-hospital mortality; a negative binomial regression model was used for hospital stay. All models were adjusted for age, sex, comorbidities (hypertension, diabetes, myocardial ischaemia, arrhythmia, heart failure, stroke, peripheral vascular disease, asthma/chronic obstructive pulmonary disease, liver dysfunction, renal dysfunction, and anaemia), type of surgery, anaesthesia method, anaesthesia induction period, type of induction agents, and use of inhalational anaesthesia. Abbreviations: BMI Body mass…

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  Fig. 3. Association Between Body Mass Index and Post-induction Hypotension Using Restricted Cubic Spline and BMI Distribution Histogram Restricted cubic spline (RCS) analysis illustrating the non-linear relationship between body mass index (BMI) and the odds of post-induction hypotension (PIH). The reference point was set at a BMI of 24.2 kg/m² (median value). The y-axis represents the odds ratio (OR) for PIH at each BMI value compared to the reference. The two red dashed vertical lines mark the BMI values where the estimated OR for PIH equals 1. The blue density histogram shows the distribution of BMI in the study cohort. Logistic regression models were adjusted for age, sex, comorbidities (including hypertension, diabetes, myocardial ischaemia, arrhythmia, heart failure, stroke, peripheral vascular disease, asthma/chronic obstructive pulmonary disease, liver dysfunction, renal dysfunction, and anaemia), type of surgery, anaesthesia method, induction period, type of induction agents, and inhalational anaesthesia use. Abbreviations: BMI Body mass index, PIH Post-induction hypotension, OR Odds ratio, CI Confidence interval

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  Fig. 4. Association Between Body Mass Index and Post-induction Hypotension Stratified by Sex, Age, Hypertension, and Diabetes Restricted cubic spline (RCS) models showing the non-linear association between body mass index (BMI) and the risk of post-induction hypotension (PIH) in four subgroups: (A) Sex, (B) Age group, (C) Hypertension status, and (D) Diabetes status. P-values indicate interaction between BMI and the stratification variable. Logistic regression models were adjusted for age, sex, comorbidities (hypertension, diabetes, myocardial ischaemia, arrhythmia, heart failure, stroke, peripheral vascular disease, asthma/chronic obstructive pulmonary disease, liver dysfunction, renal dysfunction, anaemia), type of surgery, anaesthesia method, induction period, type of induction agents, and use of inhalational anaesthesia. Abbreviations: BMI Body mass index, PIH Post-induction hypotension, OR Odds ratio, CI Confidence interval