AcademyHealth 2008

VA Center for Clinical Management Research

VA Ann Arbor Healthcare System*

Profiling Hospital Differences in the Quality of CABG Surgery Using Quality-Adjusted

Life Expectancy

Profiling Hospital Differences in the Quality of CABG Surgery Using Quality-Adjusted

Life Expectancy

Justin W. Timbie, PhD*David M. Shahian, MD

Joseph P. Newhouse, PhDMeredith B. Rosenthal, PhD

Sharon-Lise T. Normand, PhD

Funding: Alfred P. Sloan Foundation

AcademyHealth 2008

Outline

• Context: Summary measures of quality

• Framework: Use 10 quality measures to estimate survival and utility outcomes.

• Illustration: Estimate QALY outcomes for 14 hospitals performing CABG surgery.

• Discussion: How to generalize the approach

AcademyHealth 2008

Background: Composite Measures

Main issues:

1) Weights have limited (or no) clinical basis.

2) Assigning “importance” weights is a challenge.

3) Weighting of mortality vs. other measures is conceptually weak.

Approach Example

Equal weights CMS Hospital Quality Demos

“Importance” weights The Leapfrog Group

“All-or-nothing” Institute for Healthcare Improvement

Latent variable model

AcademyHealth 2008

Rationale for QALY composite measure

• QALY = Quality-Adjusted Life Year• Incorporates mortality and morbidity effects (via utility) of poor

quality.• Time horizon is one year.

QALYs address main issues:1) Weights are based on clinical outcomes.

2) Weights determined by fitting survival model and utility weights from literature.

3) Mortality/morbidity tradeoff determined by utility.

AcademyHealth 2008

CABG Quality Measures

Measure % Failure

1 Preoperative beta-blocker 15.2

2 Use of internal mammary artery 4.9

3 Aspirin at discharge 5.2

4 Beta-blocker at discharge 15.2

5 Anti-lipids at discharge 21.6

6 Stroke (lasting >72 hours) 1.2

7 Deep sternal wound infection 1.2

8 Renal failure 2.9

9 Prolonged ventilation (>24 hours) 11.9

10 Re-operation 2.2

Source: Massachusetts Data Analysis Center (Mass-DAC), 2004.

AcademyHealth 2008

Utilities for CABG complications

Complication Duration Estimate

Reoperation 30 d 0.78

Prolonged ventilation 30 d 0.76

Renal failure 30 d 0.63

Deep sternal wound infection 60 d 0.58

Stroke 1 y 0.52

Renal failure with hemodialysis 1 y 0.49

AcademyHealth 2008

Estimating QALYs

Unit Survival Model

Patient j

in

hospital i

P(Survival|β0i,X,Q)ij

AcademyHealth 2008

Estimating QALYs

Unit Survival Model

Patient j

in

hospital i

P(Survival|β0i,X,Q)ij

Patient j in any hospital

P(Survival|μ,X,Q)ij

AcademyHealth 2008

Estimating QALYs

Unit Survival Model Complication Models

Patient j

in

hospital i

P(Survival|β0i,X,Q)ij 1. P(Complication|β0i,X)ij

2. EU(Stroke)ij

= P(Stroke)*U(Stroke) +

1-P(Stroke)*U(No Stroke)

3. EU (All comps)ij = Π EU

Σ EdU

Patient j in any hospital

P(Survival|μ,X,Q)ij 1. P(Complication|μ,X)ij

2. Same as above

3. Same as above

AcademyHealth 2008

Estimating QALYs

Unit Survival Model Complication Models

Patient j

in

hospital i

P(Survival|β0i,X,Q)ij 1. P(Complication|β0i,X)ij

2. EU(Stroke)ij

= P(Stroke)*U(Stroke) +

1-P(Stroke)*U(No Stroke)

3. EU (All comps)ij = Π EU

Σ EdU

Patient j in any hospital

P(Survival|μ,X,Q)ij 1. P(Complication|μ,X)ij

2. Same as above

3. Same as above

Incremental QALY = P(S)*EU – P(S)*EU

Hospital i Any hospital

AcademyHealth 2008

AcademyHealth 2008

AcademyHealth 2008

Key findings

• Incorporating longer-term survival and utilities can change inferences on outliers.

• Low incidence of major complications.• Limitations:

– Process measures had negligible survival effects.– Disagreement on utility estimates and aggregation

method.

AcademyHealth 2008

Generalizing the QALY approach

• Consider excluding some process measures from QALY composite.

• Surgical: – Mortality and complications are key measures.

• Medical:– 30-day mortality is current standard.– Readmission, functional status measures on horizon.

• Safety: – NQF “Safe Practices”: Large quality problem, high

morbidity.

AcademyHealth 2008

AcademyHealth 2008

QALY composites for diabetes

• Measures: – BP < 130/80 mmHg– A1c < 7%– LDL < 100 mg/dL

• QALYs summarize implications of current risk factor levels relative to goals. – Survival outcomes simulated via Markov model.– Utilities reflect future complications and cardiac events.

• Medical Care 2007;45:315-321.

5-fold greater odds of mortality (over 10 years)