cost-effectiveness of pressure ulcer prevention initiated ... · • endorsed by public health...

Cost-effectiveness of Pressure Ulcer Prevention Initiated by Machine Learning

William V. Padula, PhD, MS, MScAssistant Professor

Department of Health Policy & Management

Twitter: @DrWmPadula

© 2015/2016, Johns Hopkins University. All rights reserved.

Acknowledgements• Unrestricted grant from AHRQ (1-F32-HS023710-01) • Collaborators:

• David Meltzer, MD, PhD• Peter Pronovost, MD, PhD• Mary Beth Makic, PhD, RN• Heidi Wald, MD, MSPH• John Bridges, PhD• Aelaf Worku, MD• Dane Moran, MPH• Andy Millis, MPH

• NPUAP Board of Directors• Commission on Magnet, ANCC Magnet® Recognition Program• Molnlycke Health Care – Speakers Bureau and Consultant


Overview• Introduction to Cost-Effectiveness Analysis

• Background on Pressure Ulcers

• Value of Preventing Hospital-acquired Conditions

• New Findings with Machine Learning Methods


Introduction to Cost-effectiveness Analysis

Need for measure of “Efficiency”

• Academic medicine• Government, especially outside the U.S.

– e.g. in U.S., Office of Technology Assessment, CDC– e.g. in U.K., National Institute for Clinical Excellence

• Private payers• Clinicians• Pharmaceutical and Biomedical companies

– “Pharmacoeconomics”– “Health Technology Assessment”

Growth in Demand for Cost-effectiveness Analysis

• Type of analysis

• Perspective

• Definition and measurement of costs

• Definition and measurement of benefits

Methodological Issues in Cost-effectiveness Analysis

• Cost-minimization– Least expensive method to accomplish a fixed objective– Problem: assumes objective should be met

• Cost-benefit– Costs and benefits measured in dollar terms– Select all treatments for which net benefit > 0– Problem: placing dollar value on outcomes

• Cost-effectiveness: ∆cost / ∆benefit– Select treatments with lowest cost-effectiveness ratios

Types of Analytical Methods

Incremental Cost-effectiveness Ratio (ICER)

Effectiveness Decreases

Effectiveness Increases

Cost Increases

Never Do Cost-effective

Cost Decreases

Cost-effective

Always Do

Cost-effectiveness of Medical Interventions

• The U.S. finds most health technologies cost-effective that are < $100,000/QALY to $150,000/QALY

• By Contrast, the UK only pays for technologies < $50,000/QALY

• Patients

• Providers

• Payers – Private: HMO, consumer– Public: Medicare, Medicaid, state mental health system

• Health Care Sector– All costs exchanged in a health system by payers, providers and patients– Includes out-of-pocket costs to patient, but not their time/productivity– Considers future health system costs for changes in utilization

• Societal– Includes all costs and benefits no matter to whom they accrue– Considers time-cost of patients and caregivers, including productivity– Accounts for future costs– Used by policy analysts (i.e., Panel on Cost-Effectiveness in Health and

Medicine)

Perspective

• Specific Outcomes --> General Outcomes– Cancers detected– Cancers cured– Life-years saved– Quality-adjusted life years (QALYs) saved

• Life-years weighted by quality of life weights between 0 (death) and perfect health (1)

• “Cost-utility analysis”• Endorsed by Public Health Service Panel on Cost-effectiveness in

Health and Medicine

– Disability-adjusted life years (DALYs) saved

Benefit / Effectiveness Measures

Wasteful Spending


Background on Pressure Ulcers


What are Pressure Ulcers?

NPUAP 2014

• Localized injury to skin and underlying tissue occurring over a bony prominence from pressure with friction/shear

• Recognized contributing factors:– Higher Acuity– Older Age– Malnourishment

• Hospital-acquired Pressure Ulcers (HAPUs)– Not present on admission (POA)– Costly to hospitals


Burden of Hospital-acquired Pressure Ulcers (HAPUs)

Berwick: Eliminating Waste in U.S. Health Care

$36-45 Billion spent on “failures of care delivery”

Financial Impact of Pressure Ulcers

• 4.5% HAPU incidence

• $500-130,000+ per case

• $11 billion/year in U.S.

Pressure Ulcers represent 0.3% of all healthcare expenditures

Berwick, JAMA 2012; Lyder, JAGS 2012; Kuhn, Nurs Econ, 1992; Padula, Med Care 2011


Evidence-based Practice Guidelines for HAPU Prevention

– Risk-assessment with Braden Scale8

– Initiate complete protocol for high-risk individuals

NPUAP 2014


Value of Preventing Hospital-acquired Pressure Ulcers

• Main comparators– Do-Nothing: Inconsistent

EBPs implementation– Prevention with EBPs

• Evidence-based practices for pressure ulcer prevention are cost-effective– Invest $55/patient/day in EBPs– Cost-saving

• *If practiced consistently*

Case #1: Decubitus Patient – Bed Refusal

• 55 yo white woman, obese (BMI=40)

• Wheelchair bound for ~15 years

• Postoperative CABG, pain in legs

• Stage I Pressure Ulcers on sacrum & heels

• Refuses to have air-fluidized bed brought in because too uncomfortable

Case #2: Rectal Bleeding – Colon Cancer?

• 61yo underweight black male

• Admitted for unexpected weight loss

• Occult blood in stool• Family Hx of colon

cancer• Patient not wanting to

get a colonoscopy…

Case #3: Menorrhagia/Anemia -Patient refusing blood transfusion

• 44yo Female, identifies as Jehovah’s Witness

• Menorrhagia and low Hgb level (2.5 g/dL)

• Religion does not allow her to receive a transfusion

• Can the medical team do anything else to help her?

Case #4: EOL Female wishing to be resuscitated

• 95yo Hasidic female with multiple CCs

• CKD, CAD, CABG, CHF, DM, PVD, amputation

• Admitted 2mo ago for AMI

• MD recommends DNR and palliative care

• The patient chooses to forgo palliative care/DNR – wants to survive at all costs


ICERs for Cases from Each Perspective

Value is in the Eyes of the Beholder


New Findings on Value with Machine Learning


EPUAP/NPUAP International Guidelines for Pressure Ulcer Prevention

– Risk-assessment with Braden Scale– Initiate complete protocol for high-risk individuals

EPUAP/NPUAP 2014

Item Limited - Unimpaired

Mobility 1 to 4

Sensory Perception 1 to 4

Nutrition 1 to 4

Activity 1 to 4

Moisture 1 to 4

Friction and Shear 1 to 3

© 2014, Johns Hopkins University. All rights reserved.© 2015/2016, Johns Hopkins University. All rights reserved.

Conceptual Framework: Leveraging Risk Data to Implement High-value Care


Our Study• Objective: to analyze the cost-utility of hospital resources to risk-

assess all patients or select risk-groups identified by machine learning compared to current standard of care

• Comparators• Implement pressure ulcer prevention on ALL patients• Prevention to select risk-groups of higher value

• Approach: Markov Model• Time Horizon: 1-day cycles for 365 days, or until patient discharge• Perspective: U.S. Societal• Main Outcome Measure: Cost (2015 USD) per Quality-adjusted Life

year (QALY) at a willingness-to-pay of $100,000/QALY• Sensitivity Analyses: Univariate and Multivariate Probabilistic• Data Source: Academic Medical Center EHR warehouse


Data Source• EHR Clinical Data Repository

• 600 bed Academic Medical Center using EPIC• 2 Certified Wound, Ostomy and Continence Nurses (CWOCNs)• Over 90,000 patient-encounters (2011-2014)• 7,000+ potential predictors of HAPU risk

- Age at admission- Braden Scores- Diagnoses

• Inclusion Criteria: AHRQ Patient-Safety Indicator 3, v3.2• Adults with Stage III, IV and Unstageable Pressure Ulcers• Pressure Ulcer not Present-on-Admission (POA)


Entity-Relationship Diagram of Data StorageImportant for Data Organization to Create a Markov Model


Modeling Transition ProbabilitiesA 10-state Markov model

Multi-state Modelling with R:the msm package

Version 1.6.4

Christopher JacksonMRC Biostatistics Unit

Cambridge, U.K.


Study Population


Transition Probabilities of Pressure Ulcers by Braden Score Age-adjusted

Minimal Risk At Risk Moderate

Risk High Risk Very High Risk Discharge PSI-03

Minimal Risk 0.0355 0.0139 0.004 0.0025 0.0005 0.9367 0.0068

At Risk 0.036 0.0152 0.0046 0.003 0.0006 0.9246 0.0159

Moderate Risk 0.0342 0.0157 0.0051 0.0035 0.0007 0.9051 0.0357

High Risk 0.033 0.0161 0.0055 0.0039 0.0008 0.8892 0.0515

Very High Risk 0.0323 0.0166 0.0058 0.0042 0.0009 0.8752 0.065

HAPU indicates hospital-acquired pressure ulcer; Minimal Risk, Braden score 19-23; At Risk, Braden score 15-18; Moderate Risk, Braden score 12-14; High Risk, Braden score 9-11; Very High Risk, Braden score <9


Model Parameters


Expected Results

Low cost to risk-stratify the population for Pressure Ulcers, but in general, at a deterioration in QALYs


Results of Sensitivity AnalysesProbabilistic Sensitivity Analysis

• Follow-up risk-assessment only among patients with Braden scores <19 dominated standard care ($1,745, 14.03 QALYs) in 50.89% of simulations


Discussion• Pressure Ulcer Prevention is cost-effective

• Costs approximately $100/day per patient• Cost-effective in all patients at $2,000/QALY• Risk-stratifying highest-risk patients (<19) is of

higher value

• Limitations• Generalizability: Only one hospital-EHR• Not all pressure ulcers are coded as a PSI-03• Uncertainty of inter-rater reliability in Braden Scores


Conclusions

• Using real-world data, we maintain that risk-assessment among all patients cost-effectively prevents pressure ulcers

• Hospitals should encourage nurses’ adherence to EPUAP/NPUAP International Guidelines to benefit patients instead of cost-cutting


Thank you

Follow me on Twitter:@DrWmPadula#econeval

cost-effectiveness of pressure ulcer prevention initiated ... · • endorsed by public health...

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