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Background Teaching hospitals often show better surgical outcomes for mortality based measures than non-teaching hospitals At the same time, it is well known that blacks obtain a disproportionate share of their care at teaching hospitals, yet do not generally display better adjusted outcomes than whites
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Teaching Intensity, Race and Surgical Outcomes
Jeffrey H. Silber
The University of PennsylvaniaThe Children’s Hospital of Philadelphia
AcknowledgmentsJeffrey H. Silber, M.D., PhDPaul R. Rosenbaum, PhDPatrick S. Romano, MD
Amy K. Rosen, PhDYanli Wang, MS
Michael J. Halenar, BAOrit Even-Shoshan, MS
Kevin G. Volpp, MD, PhD
The University of Pennsylvania School of Medicine; The Wharton School, The Children’s Hospital of Philadelphia,
The University of California, Davis, and Boston University; The U.S.Veterans Administration Hospitals in
Philadelphia and Boston.Funding: NHLBI (R01 HL082637) and VA (IIR 04-202)
Background• Teaching hospitals often show better
surgical outcomes for mortality based measures than non-teaching hospitals
• At the same time, it is well known that blacks obtain a disproportionate share of their care at teaching hospitals, yet do not generally display better adjusted outcomes than whites
Background• While black patients have generally been
observed to have worse outcomes, some studies [see Polsky and Volpp HSR 2008 and Volpp and Polsky HSR 2007], report that 30-day mortality may actually be lower in blacks than whites, with this lower mortality rate switching to higher mortality over a longer time horizon.
Background• In our recent work [Anesthesiology 2007], we
reported a clear difference in length of procedures by race, especially at teaching hospitals.
• Using Medicare anesthesiologist billing data in Pennsylvania, controlling for procedure and patient comorbidities, surgery on black patients took on average 30 minutes longer than similar surgery on white patients. After controlling for the hospital, there remained a significant 7 to 9 minute difference, with some teaching hospitals displaying racial differences of 15 minutes.
Motivation• Given:
– (1) the differences observed in outcomes between teaching-intensive and non-teaching hospitals
– (2) the high proportion of black patients at teaching-intensive hospitals
– (3) Differential procedure time between black and white patients (potentially reflecting differential attending involvement)
• Any analysis of differential outcomes across hospitals with different teaching intensity must include an analysis that examines the interaction of teaching intensity and race.
Aims
• To determine whether there are improved mortality outcomes at teaching intensive hospitals, and if so was this based on lower complication rates or lower death rates after complications (failure-to-rescue)
• To determine whether differential outcomes for black patients observed between teaching-intensive and non-teaching hospitals is similar to those of white patients
Study Population
• MEDPAR data from 2000-2005 for the entire US
• Include General Surgery, Orthopedics and Vascular Surgery
• Exclude patients in Managed Care plans• Choose the first admission for each patient• 3270 Acute Care Hospitals• 4.6 million patients
The Resident to Bed Ratio• We utilized the Resident-to-Bed Ratio as our
measure of teaching intensity• The RB ratio is defined as the total number of
residents at a hospital divided by the hospital’s average daily census (ADC), as reported to Medicare using Medicare Cost Reports
• RB ratios are classified as follows:– RB = 0 (non-teaching)– 0<RB<0.05 (very minor teaching)– .05<RB<0.25 (minor teaching)– 0.25<RB<0.6 (major teaching hospitals)– RB > 0.6 (very major teaching hospitals).
Statistical Methods
• Risk Adjustment – Procedures, Elixhauser Comorbidities, Age,
Sex– Interactions: comorbidities, procedures
• Models – Logistic regression with and without fixed
effects for hospital– Random effects model (SAS GLIMMIX)
clustering by hospital
RESULTS
RB Ratio and Hospital Characteristics Non- Very VeryHospital Variable Teaching Minor Minor Major MajorRB Ratio 0 0<RB<0.05 .05<RB<.25 .25<RB<.6 .6<RB<1.1_________________________________________________________________________N. Hospitals (%) 2251 307 409 194 109
(68.83%) (9.38%) (12.51%) (5.93%) (3.33%)
N. Patients (%) 2,247,368 693,023 999,633 450,695 240,489 (48.53%) (14.96%) (21.58%) (9.73%) (5.19%)
Hosp Beds: Median 118 260 295 383 477
Hosp Surg Vol: Median 1192 3423 4058 4681 7429
Technology Index (%) 19 51 62 59 83
NTB Ratio Median 1.29 1.38 1.48 1.60 2.02
Nurse Mix: Median 0.85 0.90 0.92 0.94 0.95
Patient Characteristics by Race and RB RatioVariable RB = 0 RB > 0.6 RB = 0 RB > 0.6
Black Black White White
# Patients 114,448 28,899 2,080,165 199,686
Age (mean) 75.68 74.91 76.66 75.43
Male % 33.83 34.98 37.66 44.30
# Comorbids (mean) 2.76 2.60 2.07 2.02
HBP % 72.87 73.49 57.52 57.17
COPD % 16.38 15.40 19.40 16.46
Diabetes % 28.57 26.40 16.24 14.90
CHF % 15.82 14.13 11.89 9.70
PeripheralVasc Dis % 11.91 11.30 6.95 9.18
Renal Failure % 8.38 6.58 2.81 2.36
Patient Characteristics by Race and RB Ratio
Variable RB = 0 RB > 0.6 RB = 0 RB > 0.6 Black Black White White
N. Patients 114,448 28,899 2,080,165 199,686
Death Rate (%) 5.06 5.21 4.23 3.94
Comp. Rate (%) 51.5 50.2 42.9 41.9
Failure Rate (%) 9.84 10.37 9.91 9.40
The Resident-to-Bed Ratio and its Association with Mortality, Complication and Failure-to-Rescue
RB Ratio 95% CI P-value N (millions) Rate (%) C-Stat
Mortality 0.86 (0.85, 0.88) p<0.0001 4.66 4.23% 0.850
Mortality (RE) 0.92 (0.89, 0.95) p<0.0001 4.66 4.23% 0.853
Complications 1.00 (0.99, 1.00) p=0.141 4.66 43.39% 0.764
Compl. (RE) 0.99 (0.97, 1.01) p=0.60 4.66 43.39% 0.775
FTR 0.86 (0.85, 0.88) p<0.0001 2.02 9.75% 0.775
FTR (RE) 0.91 (0.88, 0.94) p<0.0001 2.02 9.75% 0.781
Adjustments included patient covariates but not race or income. Results including income adjustment yielded almost identical results. RB ratio reported as RB = 0 versus RB = 0.6
Influence of RB Ratio and Race on the Odds of 30-day Mortality
Model 1 Model 2 Model 3 Model 4 Fixed Effects Random EffectsBlack Vs. White 0.940.94 0.920.92(RB=0) (0.92, 0.96) (0.92, 0.96) (0.90, 0.94) (0.91, 0.94)
p<0.0001 p<0.0001 p<0.0001 p<0.0001
RB Ratio x 1.051.26 1.131.18Black (1.00, 1.10) (1.20, 1.31) (1.08, 1.20) (1.13, 1.24)
p=0.03 p<0.0001 p<0.0001 p<0.0001
RB Ratio x 0.84White (0.82, 0.85) ------ ------ ------
p<0.0001
RB Ratio 0.840.89 ------ (0.83, 0.84) ------ (0.87, 0.90) p<0.0001 p<0.0001
Note: In these tables we report models for the combined surgery group only. Separate models usinggeneral surgery, orthopedics or vascular surgery without and with adjustment for the individual hospital(a fixed effects approach) produced mostly similar results. Note also, RB change is 0 vs. 0.6
Influence of RB Ratio and Race on the Odds of Complications
Model 1 Model 2 Model 3 Model 4 Fixed Effects Random EffectsBlack Vs. White 1.261.26 1.271.27(RB=0) (1.24, 1.27) (1.24, 1.27) (1.26, 1.29) (1.26, 1.28)
p<0.0001 p<0.0001 p<0.0001 p<0.0001
RB Ratio x 0.970.99 0.980.98Black (0.95, 0.99) (0.97, 1.01) (0.96, 1.00) (0.95, 1.02)
p=0.004 p=0.25 p=0.09 p=0.13
RB Ratio x 0.98White (0.98, 0.99) ------ ------ ------
p<0.0001
RB Ratio 0.980.98 ------ (0.98, 0.99) ------ (0.96, 1.00) p<0.0001 p=0.94
Note: In these tables we report models for the combined surgery group only. Separate models usinggeneral surgery, orthopedics or vascular surgery without and with adjustment for the individual hospital(a fixed effects approach) produced mostly similar results. Note also, RB change is 0 vs. 0.6
Influence of RB Ratio and Race on the Odds of Failure-to-Rescue
Model 1 Model 2 Model 3 Model 4 Fixed Effects Random EffectsBlack Vs. White 0.870.87 0.840.85(RB=0) (0.85, 0.89) (0.85, 0.89) (0.82, 0.86) (0.84, 0.86)
p<0.0001 p<0.0001 p<0.0001 p<0.0001
RB Ratio x 1.041.24 1.141.18Black (1.00, 1.09) (1.18, 1.30) (1.08, 1.20) (1.12, 1.24)
p=0.06 p<0.0001 p<0.0001 p<0.0001
RB Ratio x 0.84White (0.83, 0.86) ------ ------ ------
p<0.0001
RB Ratio 0.840.89 ------ (0.84, 0.85) ------ (0.87, 0.91) p<0.0001 p<0.0001
Note: In these tables we report models for the combined surgery group only. Separate models usinggeneral surgery, orthopedics or vascular surgery without and with adjustment for the individual hospital(a fixed effects approach) produced mostly similar results. Note also, RB change is 0 vs. 0.6
Unadjusted Mortality
0
1
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6
Black White
Race
Mor
talit
y Ra
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RB=0
RB=0.6
Figure 1A: Standardized Mortality Rates
0
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5
White Black
Race
Mor
talit
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ate
RB=0
RB=0.6
Unadjusted Complications
0
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White Black
Race
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ate
RB=0RB=0.6
Figure 1B: Standardized Complication Rates
0
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White Black
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RB=0
RB=0.6
Unadjusted Failure-to-Rescue
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Rate
RB=0
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Figure 1C: Standardized Failure-to-Rescue Rates
0
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White Black
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FTR
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RB=0
RB=0.6
Summary• Higher teaching intensity is associated with
lower mortality• This better mortality is due to better failure-to-
rescue and not lower complications• However, when blacks are treated at teaching-
intensive hospitals they do not experience the same relative benefits as their white counterparts when each group is compared to their outcomes at less teaching-intensive hospitals
Conclusions
• Teaching intensive hospitals must seek to better understand why blacks do not seem to reap the same relative benefits of teaching hospitals as their white counterparts
• These findings are especially concerning, as all patients in this report have Medicare
• These findings may aid in explaining why blacks may sometimes avoid admission to teaching hospitals, despite close proximity
