Hospital Readmissions Research: in search of potentially avoidable costs

1
Hospital Readmissions Research in search of
potentially avoidable costs

• Bernard Friedman, PhD
• Center for Delivery, Organization, and Markets
• AHRQ Conference, 2008

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Agenda

• Brief overview of some AHRQ internal research on
  readmissions over the past several years.
• Then a more detailed presentation on recent work
  in progress.
• If voice doesnt hold out, there is a poster on
  this project in the Cafe.
• Finally, a few words on how HCUP team is trying
  to make new tools available to outside analysts
  to study readmissions.

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Published Studies

• 1.) Joanna Jiang was the lead author at AHRQ on
  several published studies of diabetes discharges.
• One finding was that half of the discharges or
  hospital costs in a year are for people with
  multiple discharges for diabetes and its
  complications.
• 2.) I examined (with Joy Basu) all readmissions
  within 6 months for people with 16 Potentially
  Preventable initial admissions.
• Large variety of principal diagnoses for the
  RE-admissions
• Just the Potentially Preventable RE-admissions
  within 6 months had a projected national cost of
  about 1.4 Billion in todays . This covered 4
  states with 15 of the U.S. population.

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(contd)

• 3.) A recently accepted paper (with Joanna Jiang
  and Anne Elixhauser),
• Costly Hospital Readmissions and Complex Chronic
  Illness
• shows importance of the number of different
  chronic conditions in predicting readmission
  rates and annual cost.
• 4.) Bill Encinosa and Fred Hellinger recently
  published The Impact of Medical Errors on 90 Day
  Costs and Outcomes An Examination of Surgical
  Patients.
• All projects except the last one used our HCUP
  databases at AHRQ
• we receive statewide discharges from 40 Partners,
  all-payers covered
• a dozen Partners have provided encrypted patient
  identifiers that we refine by checking the age
  and gender of each supposed re-hospitalization.

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Do patient safety events contribute to
readmissions?

• Ongoing study for presentation in more detail.
• Under review at a journal. Already had a
  revision, but well be happy to have more
  suggestions.
• B. Friedman, Joanna Jiang, William Encinosa, Ryan
  Mutter

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Objectives

• To report 1-month and 3-month hospital
  readmissions, as well as deaths, after major
  surgical procedures in adults using a large
  multi-state and multi-payer database in 2004.
• To test whether 9 selected patient safety events
  contribute to these outcomes after controlling
  for measures of severity of illness and the
  presence of unrelated chronic conditions.

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Background/Motivation

• A meta-analysis of small scale studies using
  clinical chart review found that better quality
  of care was associated with reduced readmission
  rates (Ashton, 1997).
• Health plans and many patients would benefit from
  a reduction in safety events and readmissions.
• BUT, hospitals and physicians do not always have
  an incentive to reduce readmissions (especially
  in Medicare and Medicaid). And there is a
  question if hospitals yet have adequate incentive
  to reduce safety events. (Mello et al., 2007)

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Timeliness

• Starting with FY2009, CMS will be collecting data
  on some safety events and other never events.
• Voluntary to be used for public reporting
• Several AHRQ Patient Safety Indicators. Some
  events measured differently.
• when affect Medicare payment? Only postoperative
  infections so far.

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Study Design

• Healthcare Cost and Utilization inpatient
  discharge databases for 7 dispersed states CA,
  FL, MO, NY, TN, UT, VA in 2004
• Adults in surgical DRGs, not related to pregnancy
  or delivery
• Remove any rehospitalization that was
  birth-related or due to trauma.
• Multinomial logistic regression model for 3
  mutually exclusive outcomes death, readmission,
  or discharge without readmission. The model
  yields simultaneously a relative risk of death
  and a relative risk of a readmission.
• Control for
• severity level (using APR-DRG software)
• unrelated chronic comorbidities (downloadable
  software from AHRQ)
• payer group
• 15 common DRGs at the initial admission

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Selected Safety Events in Surgical Patients

• Excluded safety events with more than a third of
  instances that were present on admission in two
  states with such data Houchens, et al., 2008.
• Example
  Iatrogenic Pneumothorax
• Numerator
• Discharges with ICD-9-CM code of 512.1 in any
  secondary diagnosis field among cases meeting the
  inclusion and exclusion rules for the
  denominator.
• Denominator
• All surgical discharges age 18 years and older
  defined by surgical DRGs, subject to exclusions
  below.
• Exclude cases
• MDC 14 (pregnancy, childbirth, and puerperium)
• with diagnosis code of chest trauma or pleural
  effusion
• with an ICD-9-CM procedure code of diaphragmatic
  surgery repair
• with any code indicating thoracic surgery, lung
  or pleural biopsy, or assigned to cardiac surgery
  DRGs
• Full specifications of all Patient Safety
  Indicators used in study
• lthttp//www.qualityindicators.ahrq.gov/ps
  i_overview.htmgt

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Selected Patient Safety Risks
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Key Findings

• The 3-month readmission rate was less than 17
  for those with no safety event but 24.8 when a
  safety event occurred.
• 2/3 of readmissions within 3 months occurred
  within the first month.
• The relative risk ratio for readmission due to
  any safety event, adjusted for all other factors
  was 1.20 (1.165-1.235), Plt.001
• The in-hospital death rate was 1.3 with no
  safety event but 9.2 with a safety event.
  RRR1.654 (1.562-1.752), Plt.001
• Medicare and Medicaid patients were more likely
  to have readmissions than privately insured
  patients RRR about 1.5 in each case.

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Multivariate results Relative Risk Ratios
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Discussion

• Hospital readmissions are one way that safety
  events can have costly consequences, in addition
  to deaths or more expense at the initial stay.
• A simultaneous multiple-outcome model makes sense
  (deaths tend to reduce readmissions) and is
  feasible.
• The study suggests that extensive risk adjustment
  does not eliminate the contribution of safety
  events to readmissions (surgical patients, at
  least).

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Final notes

• Although safety events were found to contribute
  to readmissions,
• the problems of effective management of chronic
  illness are probably a more important determinant
  of readmissions overall.
• This type of research is the tip of the iceberg
  made possible by a decade of development of
  safety indicators and risk adjustment by AHRQ
  staff, contractors and consultants.
• Ongoing infrastructure development for outside
  analysts to use with HCUP databases (Claudia
  Steiner and ThomsonReuters)
• We hope this will make it easier to analyze
  readmissions for large databases
• will require permission from more Partners to
  release encrypted patient identifiers.