DOI: 10.5061/dryad.m37pvmdc8
title: Outcomes and predictors of in-hospital mortality among patients admitted to the intensive care or step-down unit after a rapid response team activation: a retrospective cohort study

description: Introduction: It has been demonstrated that the implementation of rapid
 response teams (RRT) may improve clinical outcomes. Nevertheless,
 predictors of mortality among patients admitted to the intensive care unit
 (ICU) or to the step-down unit (SDU) after a RRT activation are not fully
 understood. Objective: To describe clinical characteristics, resource use,
 main outcomes, and to address predictors of in-hospital mortality among
 patients admitted to the ICU/SDU after RRT activation. Methods:
 Retrospective single-center cohort study conducted in a medical-surgical
 ICU/SDU located in a private quaternary care hospital. Adult patients
 admitted to the ICU or SDU between 2012 and 2020 were compared according
 to in-hospital mortality. A multivariate logistic regression analysis was
 performed to identify independent predictors of in-hospital mortality.
 Results: Among the 3841 patients included in this analysis [3165 (82.4%)
 survivors and 676 (17.6%) non-survivors], 1972 (51.3%) were admitted to
 the ICU and 1869 (48.7%) were admitted to the SDU. Compared to survivors,
 non-survivors were older [76 (64-87) yrs. vs. 67 (50-81) yrs.;
 p&lt;0.001], had a higher SAPS 3 score [64 (56-72) vs. 49 (40-57);
 p&lt;0.001], and had a longer length of stay (LOS) before unit
 admission [8 (3-19) days vs. 2 (1-7) days; p&lt;0.001). Non-survivors
 used more non-invasive ventilation (NIV) (42.2% vs. 20.9%;
 p&lt;0.001), mechanical ventilation (MV) (36.7% vs. 9.3%;
 p&lt;0.001), vasopressors (39.2% vs. 12.3%; p&lt;0.001), renal
 replacement therapy (15.5% vs. 4.3%; p&lt;0.001), and blood components
 transfusion (34.9% vs. 14.0%; p&lt;0.001). Independent predictors of
 in-hospital mortality were the SAPS 3 score, the Charlson Comorbidity
 Index, LOS before unit admission, immunosuppression, respiratory rate
 &lt;8 or &gt;28 ipm criteria for RRT activation, RRT activation
 during the night shift, and the need for high-flow nasal cannula, NIV, MV,
 vasopressors, and blood components transfusion. Conclusion: Multiple
 factors may affect outcomes of ICU/SDU-admitted patients after RRT
 activation. Therefore, efforts should be made to boost RRT effectiveness
 to improve patient safety.
description: <strong>Data Collection and Study
 Variables</strong> All study data were retrieved
 from an institutional yellow code data bank, and from Epimed Monitor
 System® (Epimed Solutions, Rio de Janeiro, Brazil) (19), which are
 structured electronic case report forms where patients’ data are
 prospectively entered by trained hospital case managers. All data were
 extracted by an independent research assistant who did not participate in
 this study. All data were fully anonymized before being made available to
 the researchers. The data were accessed and extracted on
 28/06/2021. The collected variables included
 demographics, comorbidities, Simpliﬁed Acute Physiology Score (SAPS 3
 score) (20), Sequential Organ Failure Assessment (SOFA) score (21) at
 ICU/SDU admission, Charlson Comorbidity Index (CCI) (22), Modified Frailty
 Index (MFI) (23), reason for ICU or SDU admission, the MEWS (10) at the
 moment of RRT activation, reason for RRT activation, patient’s location
 before unit admission, the time elapsed between patient deterioration and
 RRT activation, the time between RRT activation and the team’s arrival,
 destination after RRT activation (ICU or SDU), resource use and organ
 support [vasopressors, non-invasive ventilation (NIV), high flow nasal
 cannula (HFNC), mechanical ventilation (MV), renal replacement therapy
 (RRT) and blood components transfusion] during the first hour of ICU/SDU
 admission and during the ICU/SDU stay, unit and hospital length of stay
 (LOS), and hospital mortality.
 <strong>Statistical analysis</strong>
 Categorical variables were reported as absolute and relative
 frequencies, while continuous variables were presented as median with
 interquartile ranges (IQR). Normality was evaluated using the
 Kolmogorov-Smirnov test. Comparisons were performed
 between survival and non-survival patients. Categorical variables were
 compared with the X<sup>2</sup> test or Fisher’s exact test as
 appropriate. Continuous variables were compared using an independent
 <em>t</em>-test or the Mann–Whitney U test in cases of
 non-normal distribution. Univariable logistic
 regression analysis was performed to identify which predictors were
 associated with in-hospital mortality. Multivariable logistic regression
 analyses with a backward elimination procedure, including all the
 predictors showing a p-value &lt;0.20 in the univariable analysis,
 were undertaken to obtain an adjusted odds ratio (OR) along with 95%
 confidence interval (CI) and to identify which predictors were
 independently associated with in-hospital mortality. Therefore, the final
 model contained only variables significantly associated with in-hospital
 mortality after a multivariable backward logistic regression
 analysis. To avoid collinearity, the characteristics
 included in the SAPS 3 score (namely, age) and the comorbidities included
 in the CCI [namely, diabetes mellitus, chronic heart failure (CHF),
 chronic kidney disease (CKD), solid tumor, liver cirrhosis, hematological
 malignancy, and severe chronic obstructive pulmonary disease (COPD)] were
 not individually added to the model. Collinearity was assessed using the
 variance inflation factor (VIF). A VIF &gt;2.5 was arbitrarily defined
 as an indicator of collinearity. We tested the
 linearity assumption for continuous variables included in logistic
 regression models by analyzing the interaction between each predictor and
 its own log (natural log transformation) (24). Whenever the linearity
 assumption was violated, continuous numerical variables were categorized
 (24). Final multivariable logistic regression model discrimination [area
 under a receiver operating characteristic curve (AUC)] and calibration
 (Hosmer-Lemeshow chi-square statistic) were reported (25).
 Two-tailed tests were used, and statistical significance was set
 at p&lt;0.05. All analyses were performed using the IBM Statistical
 Package for the Social Sciences (SPSS) Statistics for Macintosh, version
 28 (IBM Corp., Armonk, NY, USA).
description: # Outcomes and predictors of in-hospital mortality among patients admitted
 to the intensive care or step-down unit after a rapid response team
 activation: a retrospective cohort study
 [https://doi.org/10.5061/dryad.m37pvmdc8](https://doi.org/10.5061/dryad.m37pvmdc8) ## Description of the data and file structure #### SPSS data bank The de-identified data (data_bank5.sav) presented here has been used for the analyses reported in the manuscript "Outcomes and predictors of in-hospital mortality among patients admitted to the intensive care or step-down unit after a rapid response team activation: a retrospective cohort study." This SPSS file contains baseline characteristics, Rapid Response Team (RRT) activation details, and outcome data for patients admitted to the Intensive Care Unit (ICU) or Stepdown Unit (SDU) after a rapid response team activation. To maintain data anonymization, time-related variables (namely, length of stay before unit admission, unit length, and hospital length of stay) have been modified using jitter to reduce their identifiability while preserving their analytical utility. Additionally, to mask the identification of patients, their age has been categorized according to the interquartile range. Some data points may be missing due to incomplete patient records or unavailable information in the electronic health record system. **Missing data have been left as empty cells.** ### Files and variables **Data description:** * location_beforecodeactivation: Categorical: The hospital area where the RRT was called (1 - wards; 2 - Surgical/obstetric center; 3 - hemodialysis center; 4 - other); * LOS_beforecodeactivation: Numerical: length of Stay before unit admission (days); * reason_spo2: Categorical: Reason for RRT activation altered SpO2 (0 - no; 1 - yes); * reason_respiratoryrate: Categorical: Reason for RRT activation altered respiratory rate (0 - no; 1 - yes); * reason_hypotension: Categorical: Reason for RRT activation hypotension (0 - no; 1 - yes); * reason_hypertension: Categorical: Reason for RRT activation hypertension (0 - no; 1 - yes); * reason_heartrate: Categorical: Reason for RRT activation altered heart rate (0 - no; 1 - yes); * reason_neurologicalstatus: Categorical: Reason for RRT activation altered neurological status (0 - no; 1 - yes); * reason_seizure: Categorical: Reason for RRT activation seizure (0 - no; 1 - yes); * reason_worried: Categorical - Reason for RRT activation "Worried" staff member (0 - no; 1 - yes); * reason_mews6: Categorical: Reason for RRT activation MEWS &gt;= 6 (0 - no; 1 - yes); * mews_score: Numerical: Modified Early Warning Score at RRT activation; * night_shift: Categorical: RRT activation during the night shift (0 - no; 1 - yes); - time_deterioration_activation: Numerical: Time from clinical deterioration to RRT Activation (minutes); - time_activation_teamarrival: Numerical: Time for RRT to reach the location of the code activation (minutes); - sdu_icu: Categorical: Post-Activation Allocation: Admission to ICU or SDU following RRT intervention (0 - SDU; 1 - ICU); - age_categorized: Categorical: patient age at hospital admission (years) according to IQ range; 1 (age ≤ 52); 2 (52 &lt; age ≤ 70); 3 (70 &lt; age ≤ 83); 4 (age &gt; 83); - sex: Categorical: 1 (female); 2 (male); - unitlengthstay: Numerical: ICU/SDU Length of Stay (days); - hospital_death: Categorical (0 - no; 1 - yes): Hospital death; - hospitallengthstay: Numerical: Hospital Length of Stay (days); - admissiontypecode: Categorical - Reason for ICU admission (1 - Nonoperative; 2 - Elective surgery; 3 - Emergency/Urgent Surgery); - charlson_comorbidity_index: Numerical - Charlson Comorbidity Index at ICU/SDU admission; - mfi_points: Numerical: Modified Frailty Score at ICU/SDU admission; - mfi_frail_patient: Categorical (0 - no; 1 - yes) - Frail patient (Modified Frailty Score at ICU/SDU admission); - saps3points: Numerical - SAPS 3 score at ICU/SDU admission; - sofa_score: Numerical - SOFA score at ICU/SDU admission;  - chfnyhaclass234: Categorical (0 - no; 1 - yes) - Chronic Heart Failure NYHA Class 2, 3 or 4;  - crfnodialysis: Categorical (0 - no; 1-yes): Chronic renal failure (no dialysis);  - crfdialysis: Categorical (0 - no; 1 - yes) - Chronic renal failure (no dialysis); - cirrhosis: Categorical (0 - no; 1 - yes) - Cirrhosis; - solidtumor: Categorical (0 - no; 1 - yes) - Solid tumor; * hematologicalmalignancy: Categorical (0 - no; 1 - yes) - Hematological Malignancy; * immunossupression: Categorical (0 - no; 1 - yes) - immunosupresion; * severecopd: Categorical (0 - no; 1 - yes) - Severe COPD; * arterialhypertension: Categorical (0 - no; 1 - yes) - Arterial Hypertension; * diabetes: Categorical (0 - no; 1 - yes) Diabetes Mellitus; * Mechanical ventilation first hour: categorical: resource Utilization during the first hour of ICU/SDU admission; use of Mechanical ventilation (0 - no; 1 - yes); * noninvasiveventilationfirsthour: categorical: resource Resource Utilization during the first hour of ICU/SDU admission; use of non-invasive ventilation during the first hour of ICU/SDU admission (0 - no; 1 - yes); * vasopressorsfirsthour: categorical: resource Resource Utilization during the first hour of ICU/SDU admission; vasopressors during the first hour of ICU/SDU admission (0 - no; 1 - yes); * renalreplacementtherapyfirsthour: categorical: resource Utilization during the first hour of ICU/SDU admission; renal replacement therapy during the first hour of ICU/SDU admission (0 - no; 1 - yes); * resourceisvni: categorical: resource utilization during the ICU/SDU stay; use of non-invasive ventilation during the ICU/SDU stay (0 - no; 1 - yes). * resourceismechanicalventilation: Categorical - Resource Utilization during the ICU/SDU stay - Use of Mechanical Ventilation during the ICU/SDU stay (0 - no; 1 - yes). * resourceishfnc: categorical: resource utilization during the ICU/SDU stay; use of a high-flow nasal cannula during the ICU/SDU stay (0 - no; 1 - yes).  * resourceisvasopressors: categorical: resource utilization during the ICU/SDU stay - Use of  vasopressors during the ICU/SDU stay (0 - no; 1 - yes). * resourceisrenalreplacementtherapy: categorical: resource utilization during the ICU/SDU stay; use of renal replacement therapy during the ICU/SDU stay (0 - no; 1 - yes). * transfusion: categorical: resource utilization during the ICU/SDU stay; blood components transfusion during the ICU/SDU stay (0 - no; 1 - yes). ## Code/software SPSS