Saint HCM530 case study 4

HCM530

Case Study 4

Risk Adjustment with Multivariate Techniques (New York)

The state of New York (http://www.health.state.ny.us/nysdoh/consumer/heart/1996-98cabg.pdf) has

reported risk adjusted mortality statistics for coronary artery bypass graft surgery (CABG) for a number

of years, as discussed earlier in the text. New York uses the second major approach to risk adjustment, a

multivariate model. Such models control for different kinds of patient characteristics that are likely to

influence mortality. Table 4.1 reports the multivariate model used to calculate this risk-adjusted

measure. (Textbook Case Study 6.4)

Table 4.1: Multivariable risk factor equation for CABG hospital deaths in New York State in 1998.

Logistic Regression

Patient Risk Factor Prevalence (%) Coefficient P-Value Odds Ratio

Demographics

Age …. 0.0671 <0.0001 1.069

Female Gender 28.92 0.5105 <0.0001 1.666

Hemodynamic State

Unstable 1.32 1.0423 <0.0001 2.836

Shock 0.45 1.8458 <0.0001 6.333

Comorbidities

Diabetes 30.91 0.3607 0.0010 1.434

Malignant Ventricular Arrhythmia 2.228 0.9759 <0.0001 2.654

COPD 15.97 0.5012 <0.0001 1.651

Renal Failure (no dialysis),

Creatinine > 2.5 1.89 0.9213 <0.0001 2.513

Renal Failure requiring Dialysis 1.89 0.9213 <0.0001 5.688

Hepatic Failure 0.10 3.0535 <0.0001 21.190

Severity of Atherosclerotic Process

Aortoiliac Disease 5.42 0.5481 0.0006 1.730

Stroke 7.01 0.4775 0.0016 1.621

Ventricular Function

Ejection Fraction <20 1.77 1.4235 <0.0001 4.151

Ejection Fraction 20-29 7.40 0.8183 <0.0001 2.267

Ejection Fraction 30-39 14.49 0.6186 <0.0001 1.856

Previous Open Heart Operations 5.98 0.6800 <0.0001 1.974

Intercept = -9.4988

C Statistic = 0.793

Case Questions: Answer the case questions, with research from your book, CDC, NIH and other quality sources to determine answers and solutions. You are to write a 2-3 page paper in APA formatting that addresses the following questions. Note: A minimum of two references should be used, which should include your textbook and the CDC, and others that support your responses in your paper. This is a mpaper, so your answer should not be numbered, but rather it should use titles and subtitles.

1. Which factors are supposedly related to CABG morality?

2. Which factors are the most strongly related to CABG mortality?

3. How could one derive an expected mortality rate from the multivariate model?