Impact of ACGME Duty Hour Rules on Prolonged Length of Stay

Among Medicare and VA Patients

Jeffrey H. Silber, MD, PhDProfessor of Pediatrics, Anesthesiology and

Critical Care, and Health Care Systems The University of Pennsylvania School of

Medicine The Children’s Hospital of Philadelphia

The Wharton School

AcknowledgmentsKevin G. Volpp, MD, PhD Paul R. Rosenbaum, PhD

Amy K. Rosen, PhDPatrick S. Romano, MDKamal M.F. Itani, MD

Liyi Cen, MSLanyu Mi, MS

Michael J. Halenar, BAOrit Even-Shoshan, MS

Jeffrey H. Silber, M.D., 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)

Motivation

• In 2003 the rules governing work hours for residents were changed on a national level

• In Previous work [JAMA 2007] we have reported on the influence of duty hour reform on mortality—finding little effect--no clear evidence of harm

• We now report on Prolonged Length of Stay (PLOS), a non-lethal outcome that may be associated with the change in resident work hour regulations

Overview• We wished to utilize a measure that would

reflect subtle problems that may occur from the change in resident work hour rules.

• Prolonged LOS (PLOS) may reflect subtle complications and inefficiencies in care that prolong stay

• These problems could potentially be a reflection of the change in resident duty hour regulations because: – Increased handoffs may increase errors in care

leading to complications– Increased handoffs may increase inefficiencies in the

early discharge of uncomplicated patients– More rested residents may increase efficiency and

prevent errors that may lead to prolonged stays

Defining Prolonged LOS (PLOS)

• PLOS was first introduced by Silber and Rosenbaum et al. in HSR 1999

• PLOS is based on the concept that for most admissions (conditions and procedures) there is a point in the hospitalization when “the longer you have stayed, the longer you will stay” signifying that some problem has occurred

Prolongation Point

• We can divide a hospital stay into two parts:

Length of Stay (Days)

Dai

ly R

ate

of

Dis

char

ge

Prolongation Point

Increasing discharge rate: More likely to go home as the patient stays longer

Declining discharge rate: Less likely to go home as the patient stays longer

Silber, Rosenbaum et al. HSR 1999

Rate of Discharge

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

Days

0 5 10 15 20

Computing PLOS for AMI using the Hollander-Proschan Test

Hospital Day Number going home HP T statistic T*

1 6837 8.3396E+14 -90.58

2 18697 8.4047E+14 23.09

3 27609 6.4994E+14 80.59

4 26166 3.8612E+14 88.67

5 20566 2.085E+14 79.60

6 16237 1.1544E+14 72.71

7 13187 6.5701E+13 68.60

8 10906 3.7849E+13 64.99

9 8718 2.182E+13 60.18

10 7210 1.2897E+13 56.72

11 5972 7.6654E+12 52.31

12 4762 4.577E+12 46.60

Prolongation Points and Percentage of Patients with Prolonged Hospital Stays by Conditions and Procedures (July 2002-June 2003)

Prolongation Point Percent (Hosp. Day No.) ProlongedConditions & Procedures Medicare VA Medicare VAMedicalAMI 3 3 79.7 75.4Stroke 3 3 78.9 76.4GI Bleed 3 3 56.1 53.1CHF 3 3 66.0 62.6SurgicalLap Chole 2 2 66.6 57.5R Hemicol. 6 6 65.7 71.9Sigmoidectomy 6 6 72.5 74.0O Chole 5 5 66.3 66.7Total Knee 4 5 44.1 38.6O Red Femur Fx w/ Int Fix 4 7 76.3 62.6Total Hip 4 5 48.2 47.7Exc Interverteb Disc 2 2 38.6 42.6Res AAA 6 6 70.2 71.5End Graft AA 2 3 44.8 55.7AKA 5 14 81.6 44.6Femoral-Pop Bypass 6 6 65.4 67.4Toe Amp 6 7 56.9 61.1

The longer one stays, the longer one will stay

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 10 20 30

Days in Hospital (After each specific starting point)

Pe

rce

nta

ge

Re

ma

inin

g in

Ho

sp

ita

l

Prolongation Point+0 Days

Prolongation Point+4 Days

Prolongation Point+8 Days

Prolongation Point+12 Days

Types of PLOS Measures

• PLOScost: Use LOS for death as it occurred

• PLOSoutcomes: Use LOS for death as prolonged

• We used PLOSoutcomes for this study, but results were stable using either definition

A Difference-in-Differences Study of PLOS

0

5

10

15

20

Pre (AY 2000-2003) Post (AY 2004-5)

Per

cen

t P

rolo

ng

ed

Non-teaching Teaching A Teaching B Teaching C

ACGME Reform

Measuring Teaching Intensity

• 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

• Typically, 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).

Risk Adjustment Methodology

• We performed Conditional Logistic Regression clustering on the individual hospital

• Risk adjustment was based on Elixhauser comorbidities, transfer-in status, age and sex, and principal procedure or condition

• We utilized a 6-month look-back to improve the sensitivity of the Elixhauser comorbidities

Patient Populations

• Medicare: MEDPAR data on all patients between ages 65 and 90 for Medical Conditions (AMI, CHF, Stroke, and GI bleeding) and Surgical Procedures (General Surgery, Orthopedics, and Vascular Surgery) for 2001-2005.

• VA data: Same years, ages, conditions, and procedures

RESULTS

Patient Characteristics by Diagnosis and Procedure (Medical)

Age Mean No. of

No. of Patients (mean) % Male Comorbidities

Medicare VA Medicare VA Medicare VA Medicare VA

AMI 970,184 32,170 77.3 66.9 52 99 1.9 2.0

Stroke 933,225 25,385 78.4 68.1 42 98 2.1 1.9

GI Bleed 763,765 36,035 78.5 66.9 44 98 2.6 2.3

CHF 1,196,294 50,266 78.6 69.7 44 98 2.6 2.5

Patient Characteristics by Diagnosis and Procedure (Surgical)

Age Mean No. of

No. of Patients (mean) % Male Comorbidities Medicare VA Medicare VA Medicare VA Medicare VAGen Surg Lap Chole 298,108 7,174 75.8 60.4 39 91 1.8 1.4R Hemicol 166,283 6,500 77.0 68.9 43 98 2.2 2.0Sigmoid 103,952 4,232 75.9 64.8 40 98 2.0 1.6Chole 83,172 4,576 76.4 64.4 51 96 1.9 1.6Ortho SurgTotal Knee 651,708 13,658 74.5 65.2 35 96 1.5 1.1O Red I/F Fem 300,713 3,850 81.2 72.7 25 97 2.3 2.1Total Hip 317,561 8,158 75.5 63.1 36 96 1.5 1.1Intervert Disc 94,577 7,053 73.4 52.7 49 95 1.4 0.8Vascular SurgResection AAA 63,995 2,524 75.3 69.8 75 99 2.0 1.9Graft Abd Aorta 43,856 1,927 76.3 71.3 83 100 2.1 1.9AKA 31,890 1,689 79.3 71.3 46 99 3.9 3.1Fem Pop Bypass 25,354 2,907 73.5 61.5 60 99 2.4 1.9Toe Amp 14,378 2,172 79.3 65.6 58 99 3.5 2.6

Prolongation Points and Percentage of Patients with Prolonged Hospital Stays by Conditions and Procedures

Prolongation Point Percent (Hosp. Day No.) ProlongedConditions & Procedures Medicare VA Medicare VAMedicalAMI 3 3 79.7 75.4Stroke 3 3 78.9 76.4GI Bleed 3 3 56.1 53.1CHF 3 3 66.0 62.6SurgicalLap Chole 2 2 66.6 57.5R Hemicol. 6 6 65.7 71.9Sigmoidectomy 6 6 72.5 74.0O Chole 5 5 66.3 66.7Total Knee 4 5 44.1 38.6O Red Femur Fx w/ Int Fix 4 7 76.3 62.6Total Hip 4 5 48.2 47.7Exc Interverteb Disc 2 2 38.6 42.6Res AAA 6 6 70.2 71.5End Graft AA 2 3 44.8 55.7AKA 5 14 81.6 44.6Femoral-Pop Bypass 6 6 65.4 67.4Toe Amp 6 7 56.9 61.1

Medicare Combined Medical Patients

40%

60%

80%

pre-3 pre-2 pre-1 post-1 post-2

Year

Per

cen

t P

rolo

ng

ed

VA Combined Medical Patients

40%

60%

80%

pre-3 pre-2 pre-1 post-1 post -2

Year

Per

cen

t P

rolo

ng

ed

Non-teaching (0) Very Minor/Minor (>0 & <.25)

Major (>0.25& <0.6) Very Major (>0.6)

Unadjusted Results (Medical)

Medicare Combined Surgical Patients

40%

60%

80%

pre-3 pre-2 pre-1 post-1 post-2

Year

Per

cen

t P

rolo

ng

ed

VA Combined Surgical Patients

40%

60%

80%

pre-3 pre-2 pre-1 post-1 post -2

Year

Per

cen

t P

rolo

ng

ed

Non-teaching (0) Very Minor/Minor (>0 & <.25)

Major (>0.25& <0.6) Very Major (>0.6)

Unadjusted Results (Surgical)

Odds of Prolonged Stay Post Duty Hour Reform in More vs. Less Teaching Intensive Hospitals Using Conditional Logistic Regression Controlling for Each Hospital

RB ratio x post-reform year 1 Patient categories OR (95% CI) (Number of Cases Medicare/VA) Medicare VA

Medical ConditionsStroke 1.01 (0.92, 1.10) 0.92 (0.66, 1.27)AMI 1.01 (0.93, 1.10) 0.96 (0.72, 1.29)GI Bleed 1.06 (0.97, 1.16) 1.26 (1.00, 1.58) a

CHF 0.99 (0.92, 1.06) 1.11 (0.92, 1.35)Combined Medical 1.01 (0.97, 1.05) 1.07 (0.94, 1.20)

Surgical ConditionsGeneral Surgery 1.09 (0.99, 1.21) 1.07 (0.79, 1.43)Orthopedic Surgery 1.03 (0.96, 1.10) 0.82 (0.61, 1.12)Vascular Surgery 1.16 (1.00, 1.34) 1.08 (0.66, 1.77)Combined Surgery 1.04 (0.98, 1.09) 0.94 (0.78, 1.14)

ap<0.05

Odds of Prolonged Stay Post Duty Hour Reform in More vs. Less Teaching Intensive Hospitals Using Conditional Logistic Regression Controlling for Each Hospital

RB ratio x post-reform year 2 Patient categories OR (95% CI) (Number of Cases Medicare/VA) Medicare VA

Medical ConditionsStroke 1.01 (0.92, 1.10) 0.95 (0.69, 1.31)AMI 1.06 (0.97, 1.15) 0.96 (0.72, 1.28)GI Bleed 1.09 (1.00, 1.20) 1.08 (0.86, 1.36)CHF 1.02 (0.95, 1.10) 1.18 (0.97, 1.43)Combined Medical 1.04 (0.99, 1.08) 1.05 (0.93, 1.19)

Surgical ConditionsGeneral Surgery 0.94 (0.85, 1.05) 1.02 (0.76, 1.36)Orthopedic Surgery 0.94 (0.88, 1.01) 1.04 (0.77, 1.41)Vascular Surgery 1.21 (1.04, 1.40) a 1.16 (0.71, 1.91)Combined Surgery 0.96 (0.91, 1.01) 1.00 (0.83, 1.21)

ap<0.05

Conclusions

• The change in duty hour rules did not have an overall effect on the probability of experiencing a prolonged stay

• In Medicare and VA systems, hospitals generally found ways to cope with any worsening of continuity of care associated with duty hour reform and by-and-large succeeded in avoiding the confusion and adverse consequences predicted by those opposed to the new regulations.

THE END