Race Income and Operative Time

RACE, INCOME, AND OPERATIVE TIME Jeffrey H. Silber, M.D., Ph.D. Paul R. Rosenbaum, Ph.D. Xuemei Zhang, M.S. Orit Even-Shoshan, M.S. The Center for Outcomes Research, The Children’s Hospital of Philadelphia The Department of Pediatrics, Anesthesiology and Critical Care Medicine, PENN The Department of Statistics, The Wharton School, PENN The Leonard Davis Institute of Health Economics Introduction • Operative time is a common measure of surgical quality – Longer procedures are associated with higher infection rates – Longer procedures are associated with physicians-in-training Measuring Operative Time • Until now, studies analyzing operative time in the Medicare population have been limited to single (or very few) institutions. • Operative time is usually defined as: – Surgical Time: Incision to closure – Anesthesia Time: Induction to Recovery Room Measuring Operative Time in Medicare Patients • In 1994, billing for Anesthetist and anesthesiologist services changed to a ―by the minute‖ system • Anesthetist bills (anesthesiologists, nurse anesthetists) from Medicare have never been utilized to examine procedure time on a large scale • Race and Income have not been studied with respect to procedure time Goals of this Talk • To examine the accuracy of using Anesthesia Time Units from Medicare bills to estimate operative time • To examine models that predict procedure length based on: – Patient comorbidities – Race – Income • To explore the relationship between race and operative time at individual hospitals • To discuss the implications of disparities in operative time Data • Medicare Claims on the 20 most common General Surgical procedures and the 20 most common Orthopedic procedures in Pennsylvania in 1995 and 1996, N = 77,638 • Chart Abstractions on a subset of 1931 Pennsylvania General Surgical and Orthopedic patients as part of the Surgical Outcomes Study The Anesthesia Claim • The Anesthesia Claim consists of two parts: – Base Units – Time Units • Time units are in 15 minute intervals. The first digit of the time unit is a decimal tenths digit – For example: ―25‖ for units = 15 x 25/10 minutes or 37.5 minutes • We chose the single longest anesthesia bill associated with the same day as the principle procedure Time Abstraction • We defined four specific times for abstraction on 1931 charts in the SOS study: – Start induction – Start incision – Closure – To recovery room or ICU (if going directly to ICU) Bill Time - Chart Time. N = 1931 patients from the Surgical Outcomes Study Shapiro-Wilk Test P < 0.0001 Chart Time as a Function of Claim Time, N = 1931 Median Absolute Residual (minute) 5.49 5.37 P (Wald) Variables I: Unadjusted m-Estimation II: Comorbidities, Procedures and Hospitals Int. -1.21 2.47 Slope 0.97 0.98 P .0001 .0001 R2 .89 .89 N/A <.0001 The independent variable is anesthesia claim minutes, and the dependent variable is anesthesia chart minutes. N = 1931, r = 0.94. Estimated Anesthesia Time (Minutes) for Each General Surgical Principle Procedure Procedure Abd-Perineal Rect Resect Anterior Rectal Resection N 422 685 25th %ile 210 165 Median 260 251 75TH %ile 320 255 Left Hemicolectomy Part Lg Bowel Excis Nec Sigmoidectomy 1307 507 2922 155 150 140 195 191 176 242 251 221 Lg Bowel Stoma Closure Part Sm Bowel Resection Right Hemicolectomy Unilat Thyroid Lobectomy 326 1253 34350 370 116 120 120 120 164 155 155 135 221 209 195 176 Cholecystectomy-Open Peritoneal Adhesiolysis 3883 1268 105 94 135 125 176 173 These times include principle procedures that were also accompanied with other secondary procedures billed on the same day. Estimated Anesthesia Time (minutes) for Each General Surgical Principle Procedure (when only one procedure performed) Procedure Abd-Perineal Rect Resect Anterior Rectal Resection N 84 222 25th %ile 206 146 Median 240 176 75TH %ile 285 218 Left Hemicolectomy Part Lg Bowel Excis Nec Sigmoidectomy 262 77 678 143 131 125 180 158 155 221 206 195 Lg Bowel Stoma Closure Part Sm Bowel Resection Right Hemicolectomy Unilat Thyroid Lobectomy 159 112 940 286 101 105 110 108 125 131 135 135 180 170 170 167 Cholecystectomy-Open Peritoneal Adhesiolysis 978 316 90 80 116 101 146 125 These times only include principle procedures that did not have other secondary procedures billed on the same day. Estimated Anesthesia Time (Minutes) for Each Orthopedic Principle Procedure Procedure Lumbar/Lum-sac Fus Post Other Cervical Fus Ant N 273 152 25th %ile 236 182 Median 299 240 75TH %ile 380 343 Revise Hip Replacement Spinal Canal Explor Revise Knee Replacement 971 3166 1110 180 138 143 234 180 180 311 240 230 Excision Intervert Disc Total Hip Replacement Total Knee Replacement Open Red-Int Fix Hum 2565 6215 12718 690 131 140 131 107 165 165 150 142 221 197 180 191 Partial Hip Replacement Shoulder Arthroplasty 4735 909 105 105 129 124 155 158 These times include principle procedures that were also accompanied with other secondary procedures billed on the same day. Estimated Anesthesia Time (minutes) for Each Orthopedic Principle Procedure (when only one procedure performed) Procedure Lumbar/Lum-sac Fus Post Other Cervical Fus Ant N 41 30 25th %ile 200 155 Median 240 195 75TH %ile 294 245 Revise Hip Replacement Spinal Canal Explor Revise Knee Replacement 639 1478 792 180 131 140 225 170 179 300 218 227 Excision Intervert Disc Total Hip Replacement Total Knee Replacement Open Red-Int Fix Hum 1529 4770 10551 459 122 140 131 101 155 165 150 131 196 195 180 170 Partial Hip Replacement Shoulder Arthroplasty 4102 129 105 101 125 131 150 176 These times only include principle procedures that did not have other secondary procedures billed on the same day. Estimating Anesthesia Time (Y = Mins. from bill) Parameter Multiple procedures Admit from ER Transfer In Hx Coagulopathy Hx Diabetes Minutes 18.3 .10 6.6 5.0 2.5 P-value .0001 .90 .0003 .0001 .0001 Hx Paraplegia Black Race Vs White Severity Score 1 Severity Score 2 Severity Score 3 & 4 Severity Score 0 4.7 5.2 1.5 .40 2.2 Ref .0004 .0001 .04 .59 .03 N/A N=77,638 patients, controlling for 39 (=n-1) surgical procedures and 182 (=n-1) hospitals and 34 patient covariates of which 8 are displayed above. The model was fit using m-estimation, rank R2 of 40%. Race, Income, and Procedure Time WL (n = 9,324) BM (n = 513) WM (n = 25,060) BH (n = 547) WH (n = 27,473) BL (n = 2002) 29 (<.0001) 15 (<.0001) 30 (<.0001) 15 (<.0001) 27 (<.0001) WL (n = 9,324) --- -14 <.0001) 1 (<.0001) -14 (<.0001) -2 (<.0001) BM (n = 513) --- 14 (<.0001) 0 (.8939) 12 (<.0001) WM (n = 25,060) --- -15 (<.0001) -3 (<.0001) BH (n = 547) --- 12 (<.0001) Race, Income, and Procedure Time WL (n = 9,324) BM (n = 513) WM (n = 25,060) BH (n = 547) WH (n = 27,473) BL (n = 2002) BL adjusted by 183 hosp. WL (n = 9,324) WL adjusted by 183 hosp. BM (n = 513) BM adjusted by 183 hosp. WM (n = 25,060) WM adjusted by 183 hosp. BH (n = 547) BH adjusted by 183 hosp. 29 (<.0001) 9 (<.0001) --- 15 (<.0001) 3 (0.159) -14 <.0001) -4 (.036) --- 30 (<.0001) 7 (<.0001) 1 (<.0001) 0 (.578) 14 (<.0001) 4 (.036) --- 15 (<.0001) 8 (<.0001) -14 (<.0001) -5 (.486) 0 (.8939) 5 (.052) -15 (<.0001) 1 (.570) --- 27 (<.0001) 8 (<.0001) -2 (<.0001) 1 (.069) 12 (<.0001) 4 (.014) -3 (<.0001) 1 (.126) 12 (<.0001) 0 (.848) Adjusted Differences Between Black and White Procedure Times in Pennsylvania Hospitals With the Largest Black Populations Hospital 1 No. Black 153 No. White 352 Teaching Type Major Excess Mins. (b-w) 3.3 P-Value .449 2 3 4 5 6 147 130 125 118 112 322 326 108 1319 437 V Major V Major V Major Major Major 7.0 0.8 12.2 14.3 12.1 .115 .870 .039 .001 .011 7 8 9 10 11 112 111 109 107 105 43 1006 71 505 178 Major Not Teaching V Major Major V Major -4.6 4.0 6.9 9.3 15.9 .562 .366 .308 .050 .004 12 100 1007 V Major -5.1 .274 The overall Wald test for equality was 0.029, suggesting there is variability in disparity across hospitals. General Surgical and Orthopedic Procedures Policy Implications Why might there be a disparity in operative time inside a hospital? • Reasons consistent with fairness – Unobserved severity – Admission from ER – Emergency Surgery • Reasons based on injustice – Different Surgeon/Physician-in-Training for less empowered – Risk of Litigation – Racism (Conscious or Unconscious) Why do we care about 15 minutes? Identifying the Provider: Who is holding the retractor? • In teaching hospitals it is not always clear from the chart or the claim who is performing surgery. • Is the resident doing the dissection or holding the retractor? • Differential times between the resident and the attending may help in identifying the two providers. For a typical procedure like Colectomy, which was described in Khuri et al. (Annals Surgery 2001), we can estimate the relative speed of the resident and attending, assuming the hospital location does not influence this time. VA Location Teaching NonTeach N Complexit y 3.00 2.95 % of Cases by Residents 93.64 1.42 Hours of Surgery 3.17 2.54 Mean Time Combined 3.085 8,038 1,201 From this table we can solve for the time a resident takes to perform the colectomy (TR) and the time an attending takes to perform the surgery (TA). We have two equations and two unknowns: (0.9346)TR + (0.0636)TA = 3.17 (0.0142)TR + (0.9808)TA = 2.52 Solving, we get TA = 2.523 and TR = 3.213 hours. This is very close to those in table 8 above, as almost all the surgery in the teaching hospital was with residents and almost all the surgery in the non-teaching hospital was with attendings. The Relative Risk of Getting a Resident in Black Versus White Patients TB = TR * PB,R + TA * PB,A TW = TR * PW,R + TA * PW,A Or, since PB,R + PB,A = 1and PW,R + PW,A = 1, we can write: TB = TR * PB,R + TA * (1 - PB,R ) and TW = TR * PW,R + TA * (1 - PW,R ). Hence, TB-TW = PB,R * [TR - TA] - PW,R*[TR - TA] and: [TB - TW ]/[TR-TA] = PB,R - PW,R Or: [TB - TW ]/ [PW,R][TR-TA] = [PB,R / PW,R]-1 and finally: 1+ {[TB - TW ] / {[PW,R][TR-TA]}} = [PB,R / PW,R] From Regression Data TB  TW  P  1 W P  PR  TR  TA  B R W R From External Data or Matching Studies Assuming: Relative Risk of Obtaining a Resident if a Black Patient Versus a White Patient 7.0 Relative Risk for Blacks TR-TA = 30 mins TB – TW = 15 mins 6.0 5.0 4.0 3.0 2.0 1.0 0.0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Percent of Cases Performed by a Resident if Patient is White Advantages of using Procedure Time as a Measure of Disparity • Bills available for literally all procedures performed in the OR for Medicare patients • Procedure length is highly dependent on the surgeon, not patient compliance • Procedure length is less dependent on the past history of the patient—insensitive to unobserved severity • Time is not game-able, especially since it has not been used to measure disparity in the past Conclusions • Procedure time can be well estimated with Medicare claims data • Procedure time is a function of race and income and the specific hospital, after adjustment for other patient factors • There is a significant procedure length racial disparity inside of hospitals • Mechanisms for this procedure length disparity need to be better understood Acknowledgements • This work was funded through a grant from the Leonard Davis Institute of Health Economics at PENN and supported in part from AHRQ Grant Number HS-09460 The End Additional Slides for Potential Questions TEACHING N=480 Patients Sometimes NON-TEACHING N=480 Patients Sometimes N=96 Surgeons N=480 Patients ALWAYS N=480 Patients ALWAYS TEACHING NON-TEACHING Sometimes 109 minutes P = 0.214 Sometimes 103 minutes P = 0.657 P = 0.002 P = 0.393 P = 0.0001 ALWAYS 121 minutes ALWAYS 106 minutes P = 0.002