Are Medicare Advantage Patients Less Likely to have a Readmission? (Text Version)

On September 27, 2010, Bernard Friedman made this presentation at the 2010 Annual Conference. Select to access the PowerPoint® presentation (635 KB). 

---

Slide 1

Are Medicare Advantage Patients Less Likely to have a Readmission?

Bernard Friedman, PhD
Joanna Jiang, PhD
John Bott MSSW, MBA
Claudia Steiner MD, MPH

AHRQ Conference, 2010
 

Slide 2

Background

• Hypothesis: the Advantage plans have both the motive (capitated revenue) and the means to reduce readmissions in comparison to FFS.
• Use 2006 data.
• 14 HCUP states distinguish FFS and MA payer on discharge summary.
• 5 states in HCUP also had reliable person identifiers. AZ, CA, FL, Mass, TN.
• NY could now also be used.

Slide 3

Data Preparation

• Selecting Cases:
  • Elderly Medicare beneficiary patient from urban CBSAs
  • Initial admission Jan-Sept of 2006
  • Match to Linkage file (work-saving tool, uses no actual dates, releasable => replicable study, protecting identity)
  • Use primary and secondary payer
  • Discharged alive from initial admission
• Screening out re-hospitalizations:
  • Same day transfer (using Linkage File)
  • Re-hospitalization says transferred in from another hospital
  • Pregnancy or maternity-related
  • Trauma-related principal condition (CCS 225-236)

Slide 4

Data Preparation

• Dependent Variables: at least one readmission within 30 days, 90 days
• Notes:
  • Each person enters only once, from initial admission.
  • Not addressing the "burden of readmissions", i.e., multiple readmissions within any fixed period, overlapping episodes for a person during the year.
  • ED revisits not included

Slide 5

Initial comparisons

• 266K MA initial discharges, 868K initial FFS discharges
• 30 day readmission rate: 13.7% vs. 14.4%
• 90 day readmission rate: 23.8% vs. 26.2%
• However, Medicare Advantage patients tend to be:
  • Younger
  • Less severely ill even when hospitalized
  • Less likely to be Medicaid enrolled as well
  • Less likely to have a major operative procedure.
• For more detailed comparison over 13 states, refer to Stat Brief #66.
• Other work: AHIP study of CA and NV found a lower rate of preventable admissions for Advantage enrollees.

Slide 6

Problem: Self-Selection

• Instrumental Variable approach:
  • What can we measure that could affect enrollment in an Advantage plan rather than FFS?
  • Instrument should not itself affect the likelihood of readmission.
• R = f (M, X)
• M= g(Z)
  • Z affects M but not R (standard tests for the performance of Z set)
• Z: CBSA characteristics. HMO penetration among younger insured, number of competing hospitals, available medical specialists,

Slide 7

Results of Tests

• Preliminary
• Controlling for self-selection, Medicare Advantage patients had a 9% higher likelihood of readmission in 30 days.
• Tests of the Instruments are passed
• Caveats: high users, ED visits
• Looking for a Reconciliation:
  • Enrollees do not have data to compare readmission rates when choosing a plan.
  • Health Plans do not have adequate measures of risk-adjusted readmission rates for quality improvement efforts.
  • Saving money on readmissions is not the only way to save.