Understanding Variations in Surgical Mortality:
Differences in Complications or
Failure to Rescue?
Amir A. Ghaferi, MD
AcademyHealth
Annual Research Meeting
June 28, 2009
Wide variations in surgical mortality
•
Surgical mortality is a public health issue
– 50,000 operative deaths a year in US
• Chance of death depends on where and by
whom the surgery is performed
– Surgical mortality rates vary widely
across hospitals
Strategies for reducing mortality
• Efforts to reduce surgical complications
– Pay for performance
• Medicare’s Surgical Care Improvement
Project (SCIP)
– (Non)pay for (Non)performance
• Not reimbursing for certain complications
• Uncertain whether these efforts will reduce
variations in mortality
Explaining variations in
surgical mortality rates
Hypothesis #1
Operation
Hypothesis #2
Postoperative
complication
High mortality
hospitals have higher
complication rates
Death
High mortality hospitals are
not as effective in
“rescuing” patients once
they develop a complication
Previous work assessing
Failure to Rescue
• In response to increasing use of mortality
as a quality measure
– Evaluated patients undergoing
cholecystectomy and transurethral
prostatectomy
– Patient characteristics  Complications
– Hospital characteristics  Failure to rescue
Silber et al. Med Care 1992.
Objective
To determine the extent to which
complication incidence and failure to
rescue rates explain variations in
mortality across hospitals
Methods
• Data source
– 2005-07 American College of Surgeons National
Surgical Quality Improvement Project (ACS-NSQIP)
• Subjects
– Patients undergoing inpatient general and vascular
procedures with overall mortality >1% (n=84,730)
• Outcome measures
– Operative mortality
– Postoperative complications
– Failure to rescue (ie., case-fatality among patient with
complications)
Analysis
• Ranked hospitals based on riskadjusted mortality rates
• Divided hospitals into 5 equal groups
(quintiles)
• Compared incidence of major
complications and “failure to rescue”
rates across hospitals
Variations in Mortality
6.9
7
5.8
6
4.6
5
Risk-adjusted
mortality (%) 4
4.8
3.5
3
2
1
0
1
2
3
4
Hospital Quintiles
5
Patient severity across hospitals
Median age
Gender (%male)
Non-white race
Smoking status (within past year)
ASA class ≥4
Diabetes
Chronic Obstructive Pulmonary Disease
History of Myocardial infarction
Emergency operation
Dialysis
Albumin <3.5
Hypertension
Expected mortality†
Risk-adjusted mortality
Very low
Low
Medium
High
Very high
(n=17,379) (n=16,780) (n=17,923) (n=15,953) (n=16,695)
63.6
63.0
63.9
61.7
62.4
52.0%
52.0%
51.2%
54.4%
51.6%
18.9%
14.5%
14.6%
24.1%
26.4%
22.2%
23.2%
23.8%
26.6%
27.4%
15.7%
14.3%
14.3%
16.7%
15.9%
20.2%
19.4%
19.3%
21.3%
21.7%
8.4%
8.6%
7.9%
9.2%
9.1%
1.5%
1.8%
1.3%
1.8%
1.8%
18.3%
18.8%
19.3%
18.2%
19.5%
3.6%
4.1%
3.1%
4.6%
4.7%
26.9%
23.5%
28.1%
27.4%
27.0%
58.2%
56.9%
57.6%
58.6%
59.3%
5.2%
3.5%
5.4%
4.6%
4.8%
4.8%
5.1%
5.8%
4.8%
6.9%
†Expected mortality derived from patient characteristics (age,
sex, race, comorbidities) and hospital procedure mix.
Complications and Failure to Rescue:
All operations
35
Hospital Mortality
(Quintiles)
30
27.6
26.9 26.9
Very low
24.6
25
Low
23.5
21.4
19.3
Patients (%)
20
18.4
18.0 18.2
17.5
16.2
14.9
14.7
15
12.5
10
5
0
All Complications
Major Complications
Failure to Rescue
Medium
High
Very high
Odds Ratios,
best vs. worst hospitals
Complication Incidence
1.0
1.0
Pneumonia
Prolonged mechanical ventilation
Unplanned intubation
1.0
1.7
1.2
1.7
1.9
1.3
Acute renal failure
1.7
1.0
Myocardial infarction
1.6
1.0
Pulmonary embolism
Postoperative bleed
Deep wound infection
Failure to Rescue
1.0
1.7
1.2
1.7
2.3
0.9
Organ space infection
1.9
1.0
Septic Shock
2.1
1.5
Fascial dehiscence
Stroke
1.0
0.7
1.0
3.0
Summary
• High mortality hospitals have:
– very similar complication rates
– markedly higher failure to rescue rates
• Findings consistent across individual
operations and complications
Implications
• Policy efforts aimed at preventing complications may
not reduce variation in hospital mortality
• Reducing variation in mortality will require greater focus
on the timely recognition and management of
complications once they occur
• Need to better understand processes of care and
resources related to failure to rescue
• Surviving Sepsis Campaign
• Dedicated ICU intensivists
• Higher nurse to patient ratios