title: The Agency for Healthcare Research and Quality Inpatient Quality Indicator #11 overall mortality rate does not accurately assess mortality risk after abdominal aortic aneurysm repair.
abstract: OBJECTIVE
  The Agency for Healthcare Research and Quality (AHRQ) Inpatient Quality Indicator (IQI) #11, abdominal aortic aneurysm (AAA) repair mortality rate, is a measure of hospital quality that is publically reported but has not been externally validated. Because the IQI #11 overall mortality rate includes both intact and ruptured aneurysms and open and endovascular repair, we hypothesized that IQI #11 overall mortality rate does not provide accurate assessment of mortality risk after AAA repair and that AAA mortality cannot be accurately assessed by a single quality measure.
  
  
  METHODS
  Using AHRQ IQI software version 4.2, we calculated observed (O) and expected (E) mortality rates for IQI #11 for all hospitals performing more than 10 AAA repairs per year in the Nationwide Inpatient Sample for the years 2007 to 2011. We used Spearman correlation coefficient to compare expected rates as determined by IQI #11 overall mortality rate risk adjustment methodology and observed rates for all AAA repairs in four cohorts stratified by aneurysm stability (ruptured vs intact) and method of repair (open vs endovascular).
  
  
  RESULTS
  Among 187,773 AAA repairs performed at 1268 U.S. hospitals, hospitals' IQI #11 overall expected rates correlated poorly with their observed rates (E: 5.0% ± 4.4% vs O: 6.0% ± 9.8%; r = .49). For ruptured AAAs, IQI #11 overall mortality rate methodology underestimated the mortality risk of open repair (E: 34% ± 7.2% vs O: 40.1% ± 38.2%; r = 0.20) and endovascular repair (E: 24.8% ± 9% vs O: 27.3% ± 37.9%; r = 0.08). For intact AAA repair, IQI #11 overall mortality rate methodology underestimated the mortality risk of open repair (E: 4.3% ± 2.4% vs O: 6.3% ± 16.1%; r = .24) but overestimated the mortality risk of endovascular repair (E: 1.3% ± 0.8% vs O: 1.1% ± 3.7%; r = 0.25). Hospitals' observed mortality rates after intact AAA repair were not correlated with their mortality rates after ruptured AAA repair (r = 0.03).
  
  
  CONCLUSIONS
  IQI #11 overall mortality rate fails to provide accurate assessment of inpatient mortality risk after AAA repair. Thus, it is inappropriate to use IQI #11 overall mortality rate for quality reporting. The accuracy of separate quality measures that assess mortality risk after repair of ruptured and intact AAAs, stratified by the use of open or endovascular repair, should be examined.
authors: Division of Vascular and Endovascular Surgery, University of Massachusetts Medical School, Worcester, Mass. Electronic address: william.robinson@umassmemorial.org.
authors: William P
authors: WP
authors: Robinson
authors: Center for Outcomes Research, University of Massachusetts Medical School, Worcester, Mass.
authors: Wei
authors: W
authors: Huang
authors: Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, Mass; VA Boston Healthcare System, Boston, Mass.
authors: Amy
authors: A
authors: Rosen
authors: Division of Vascular and Endovascular Surgery, University of Massachusetts Medical School, Worcester, Mass; Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, Mass.
authors: Andres
authors: A
authors: Schanzer
authors: Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, Mass.
authors: Hua
authors: H
authors: Fang
authors: Center for Outcomes Research, University of Massachusetts Medical School, Worcester, Mass.
authors: Frederick A
authors: FA
authors: Anderson
authors: Division of Vascular and Endovascular Surgery, University of Massachusetts Medical School, Worcester, Mass.
authors: Louis M
authors: LM
authors: Messina
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D001019:Aortic Rupture / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000401:mortality* / Q000592:standards; D016208:Databases, Factual; D003661:Decision Support Techniques; D057510:Endovascular Procedures / Q000009:adverse effects / Q000401:mortality* / Q000592:standards; D006302:Health Services Research; D017052:Hospital Mortality; D006761:Hospitals / Q000592:standards; D006801:Humans; D007297:Inpatients; D011237:Predictive Value of Tests; D019984:Quality Indicators, Health Care / Q000592:standards*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States