Prospective Study to Revise the Ottawa Heart Failure Risk Scale (OHFRS)

Prospective Study to Revise the Ottawa Heart Failure Risk Scale (OHFRS) CAEP Edmonton 2015

Ian Stiell MD Shawn Aaron MD Robert Brison MD Alan Forster MD Jeffrey Perry MD George Wells PhD Catherine Clement RN Bjug Borgundvaag MD Lisa Calder MD Andrew McRae MD Brian Rowe MD Department of Emergency Medicine Ottawa Hospital Research Institute University of Ottawa, Ottawa, ON Queens University, Kingston, ON University of Alberta, Edmonton, AB University of Toronto, Toronto, ON University of Calgary, Calgary, AB Funded by Canadian Institutes of Health Research No Conflicts to Declare

Acute Heart Failure in the ED: The Clinical Problem Very common presentation Potential for poor outcomes Many HF patients do not need hospital admission Little evidence to guide disposition decisions Need risk stratification tool to aid rational and safe admission decisions

Derivation of Ottawa Heart Failure Risk Scale: Acad Emerg Med 2013 Goal: Improve and standardize admission practices for HF Methods: Prospective cohort study at 6 EDs N=559 with 38% admitted Risk scale derived by logistic regression

Original Ottawa Heart Failure Risk Scale

Objectives: Prospective Validation Study (2012 2014) 1. To prospectively and clinically evaluate OHFRS in a new patient population 2014 2. To improve upon OHFRS by re evaluating predictor variables and developing a more concise model 2015

Methods 1 Design: Prospective cohort study Setting: 6 EDs of large, tertiary care Canadian hospitals Subjects: Acute HF admitted and discharged Excluded: O2 Sat < 85% on RA, HR > 120, SBP < 85 chest pain or STEMI Ethics: approved +/ informed consent Standardized Assessment: variables from history, physical routine labs, troponin, CXR, ECG quantitative NT ProBNP 3 minute walk test

Methods 2 Primary Outcome Measure serious adverse event (SAE): Death <30 days Intubation or NIV after admission MI Admission to monitored unit, or Relapse back to ED with admission within 14 days Data Analysis: Univariate association with SAE Harmonized troponin by URL Logistic regression to revise model Rounded β coefficients to create points

Patients Seen N=4,999 Patients Eligible N=1,869 Patients Enrolled N=1,100 Patient Flow Patients Excluded N=3,130 No clear increase SOB N=788 CXR shows no HF N=394 Nursing home N=376 Outside study hours N=387 Confusion, dementia N=276 Enrolled< 2 months N=200 Other N=709 Patients Not Enrolled N=769 Final Study Cohort N=1,100

Patient Characteristics Characteristic (%) N=1,100 Age in years, mean 77.7 Range 50 104 Male (%) 53.1 Ambulance arrival (%) 44.4 Duration of symptoms, hours, mean 65.5 CTAS level, median 2 Past medical history (%) Heart failure 76.7 MI/Angina 39.2 Intubation for resp distress 1.1

Patients Enrolled by Hospital (N=1,100) Foothills MC 12.8% Kingston General 12.6% Ottawa Hospital, Civic Campus 30.5% Ottawa Hospital, General Campus 14.6% U Alberta 14.0% Mount Sinai 15.6%

Patient Characteristics (N=1,100) Current Cardiac Meds (%) Diuretics 75.0 Beta blockers 68.9 Statins 62.4 Ace Inhibitors 42.5 Calcium Channel Blockers 36.3 Anti arrhythmics 6.8 Amiodarone 6.0 Sotalol 0.4 Propafenone 0.2

Patient Outcomes (%) N=1,100 Admitted to Hospital (N=629) 57.2 Critical Care Unit 9.7 Non Invasive Ventilation 3.8 Intubation 0.8 MI after admission 3.5 Death after admission 4.0 Death after discharge 1.3 Discharged from ED (N=471) 42.8 Relapse back to ED 24.2 Relapse and admitted 10.6 Death within 30 Days 1.7

Serious Adverse Events 25 20 19.4% SAEs (%) 15 10 15.6% 10.2% 5 0 Total (N=1,100) Admitted (N=629) Discharged (N=471)

Univariate Correlation with SAEs for 10 OHFRS Criteria Criterion (%) SAE No SAE (N=170) (N=930) P Value History of stroke or TIA 15.9 15.4 0.87 History of intubation 1.2 1.0 0.80 HR on ED arrival >110 20.1 11.1 <0.05 Room air SaO2 <90 32.9 22.2 <0.05 ECG acute ischemia 9.5 0.3 <0.0001 Urea >12 mmol/l 41.8 27.2 <0.001 Serum CO2 >35 mmol/l 5.4 1.4 <0.001 Troponin >0.10 ug/l 33.3 14.3 <0.0001 NT ProBNP >5,000 ng/l 63.3 49.0 <0.05 Walk test failed / too ill 70.3 53.1 <0.0001

Univariate Correlation with SAEs for Other Variables Variable (%) SAE No SAE P Value (N=170) (N=930) On Anti arrhythmic 10.6 5.6 <0.05 Ejection Fraction, mean% N=152,739 43.4 46.3 <0.05 <30% 21.7 19.5 0.53 ED Treatment IV NTG 9.4 1.8 <0.0001 BiPAP 17.1 5.0 <0.0001 Initial or repeat Troponin >URL 71.0 56.8 <0.001 >3x URL 39.1 18.7 <0.0001 >5x URL 30.2 9.9 <0.0001 NT ProBNP >10,000 ng/l 37.8 25.5 <0.05 >15,000 ng/l 27.7 13.1 <0.0001

Independent Predictors of SAE from Logistic Regression P value to enter <0.25, remove >0.10 Hosmer Lemeshow Goodness of fit p value = 0.90 Area under ROC curve = 0.72

Revised Ottawa Heart Failure Risk Scale

Classification Performance & Potential Admissions for OHFRS Cutpoints ** model developed for 1,045 patients without missing values

Observed vs Expected Probability of SAE Score Internal validation very accurate x 1,000 replications using bootstrap

Discussion Much higher admission rate Some component variables did not perform well NT probnp not useful Used troponin as multiples of URL Revised OHFRS more concise model Good internal validation

Limitations Requires further clinical validation Physicians often neglected re assessment/walk test

Conclusions: Revised OHFRS Consists of 6simple, bedside variables Estimates short term risk of SAE in acute heart failure Will assist MDs in making rational ED disposition plans Should improve and standardize admission practices, diminishing both unnecessary admissions for low risk patients, and unsafe discharge decisions for high risk patients Ultimately lead to improved safety for patients and more efficient use of hospital resources

Details of Troponin Assay by Hospital Site

Methods 3 Minute Walk Test: RN or respiratory therapist Exclude if SaO2 <90% or HR>120 Measure pulse oximetry Primary Outcome Measure serious adverse event (SAE): Death <30 days Intubation or NIV after admission MI Admission to monitored unit, or Relapse back to ED with admission within 14 days

Missed Patient Characteristics (N=769) Age in years, mean 77.7 Range 50 102 Male (%) 51.5 Admitted 60.2 Hospital (%) Ottawa H Civic, Ottawa, ON 33.3 Ottawa H General, Ottawa, ON 25.5 Foothills MC, Calgary, AB 18.7 Mount Sinai H, Toronto, ON 9.3 University Alberta H, Edmonton, AB 6.9 Kingston General H, Kingston, ON 6.4

Classification Performance of OHFRS without NT probnp (N=1,100) SAE Yes No OHFRS >2 121 410 <2 49 520 Sensitivity 71.2% Specificity 55.9% Admission 48.3%

Classification Performance of OHFRS with NT probnp (N=662) SAE Yes No OHFRS >2 95 336 <2 24 229 Sensitivity 79.8% Specificity 40.5% Admission 63.0%

Physician Comfort with Use of the OHFRS Uncomfortable 8.5% Neutral 21.8% Very Uncomfortable 3.5% Very Comfortable 17.0% Comfortable 41.5% **84 no response

Patients Seen N=4,999 Patients Eligible N=1,869 Patients Enrolled N=1,100 Patient Flow Patients Excluded N=3,130 No clear increase SOB N=788 CXR shows no HF N=394 Nursing home N=376 Outside study hours N=387 Confusion, dementia N=276 Enrolled< 2 months N=200 Other N=709 Patients Not Enrolled N=769 Final Study Cohort N=1,100 Patients Lost to Follow up N=2