Placing clinical variables on a common linear scale of empirically based risk as a step towards construction of a general patient acuity score from the electronic health record: a modelling study

Abstract

ObjectiveTo explore the hypothesis that placing clinical variables of differing metrics on a common linear scale of all-cause postdischarge mortality provides risk functions that are directly correlated with in-hospital mortality risk.DesignModelling study.SettingAn 805-bed community hospital in the southeastern USA.Participants42302 inpatients admitted for any reason, excluding obstetrics, paediatric and psychiatric patients.Outcome measuresAll-cause in-hospital and postdischarge mortalities, and associated correlations.ResultsPearson correlation coefficients comparing in-hospital risks with postdischarge risks for creatinine, heart rate and a set of 12 nursing assessments are 0.920, 0.922 and 0.892, respectively. Correlation between postdischarge risk heart rate and the Modified Early Warning System (MEWS) component for heart rate is 0.855. The minimal excess risk values for creatinine and heart rate roughly correspond to the normal reference ranges. We also provide the risks for values outside that range, independent of expert opinion or a regression model. By summing risk functions, a first-approximation patient risk score is created, which correctly ranks 6 discharge categories by average mortality with p<0.001 for differences in category means, and Tukey's Honestly Significant Difference Test confirmed that the means were all different at the 95% confidence level.ConclusionsQuantitative or categorical clinical variables can be transformed into risk functions that correlate well with in-hospital risk. This methodology provides an empirical way to assess inpatient risk from data available in the Electronic Health Record. With just the variables in this paper, we achieve a risk score that correlates with discharge disposition. This is the first step towards creation of a universal measure of patient condition that reflects a generally applicable set of health-related risks. More importantly, we believe that our approach opens the door to a way of exploring and resolving many issues in patient assessment.

Nurse Value-Added and Patient Outcomes in Acute Care

“…; Bradley et al. ; Rothman, Rothman, and Solinger ). Fourteen percent of the sample had a prior hospitalization within 30 days of admission.…”

“…, ; Bradley et al. ; Rothman, Rothman, and Solinger ). For this study, we used the first recorded RI as the admission RI, the last recorded score as the discharge RI, and the difference between admission and discharge RI as the change in clinical condition during hospitalization.…”

“…The RI score is a subtraction index from 100 with a theoretical range of −69 to 100 and higher values indicating better clinical condition and lower mortality risk. Construct validity has been evaluated in a prior study in three acute care hospitals by examining the relationship of the RI score to other indicators of clinical condition, resulting in area under the receiver operating characteristics curve (AUC) estimates of ≥0.92 for six discharge destination categories, AUC ≥0.93 when predicting 24 hours mortality, and AUC = 0.62 for 30‐day readmission (Rothman, Rothman, and Solinger ). RI scores less than 40 were associated with a fivefold increase in the risk of 30‐day mortality, and RI scores of less than 80 at discharge were associated with a nearly 2.5‐fold risk of an unplanned readmission (Rothman et al.…”

Identifying Patients at Increased Risk for Unplanned Readmission

“…The Rothman Index (RI) 11–13 is calculated and updated multiple times on a daily basis, using data from the hospital electronic medical record and novel, privately developed software adopted by the study site and clinically validated among diverse patient populations and with multiple hospitals. The RI ranged in from −6 to 99, with lower scores indicating poorer condition.…”

“Deterioration to Door Time”: An Exploratory Analysis of Delays in Escalation of Care for Hospitalized Patients

“…Severity of illness was collected at the time of initial clinical deterioration based on the Rothman Index (RI), a measure of illness acuity that incorporates 26 clinical variables including vital signs, laboratory results, cardiac rhythms, and nursing assessments into a single score. 8,[14][15][16] An RI value of less than or equal to 30 was used as a marker of severe illness. 16 The primary outcome assessed was 30-day in-hospital mortality, adjusted and un-adjusted.…”