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New York's Statistical Model Accurately Predicts Mortality Risk for Veterans Who Obtain Private Sector CABG

Authors

  • William B. Weeks,

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    • Address correspondence to William B. Weeks, M.D., M.B.A., Director, Veterans' Rural Health Initiative, VA Medical Center, White River Junction, VT. Dr. Weeks, Associate Professor, Dotty Bazos, R.N., Ph.D., Adjunct Assistant Professor, and David M. Bott, Ph.D., Research Associate, are with the Center for the Evaluative Clinical Sciences at Dartmouth and the New Hampshire Area Health Education Center, Department of Community and Family Medicine, Dartmouth Medical School, Hanover, NH. William B. Weeks is also a Principal Investigator, VA Outcomes Group, Hub Site Senior Scholar, VA National Quality Scholars Fellowship Program, Veterans Health Administration and Director, White River Junction Field Office of VHAs National Center for Patient Safety. Rosemary Lombardo, M.S., Data Manager and Statistician, and Edward L. Hannan, Ph.D., Distinguished Professor and Chair, are with the Department of Health Policy, Management, and Behavior, University at Albany School of Public Health, Rensselaer, NY. Michael J. Racz, M.A., is Research Scientist at New York State Department of Health, School of Public Health, Rensselaer, NY. Elliott S. Fisher is Co-Director, VA Outcomes Group, VA Medical Center, White River Junction, VT.

  • Dorothy A. Bazos,

  • David M. Bott,

  • Rosemary Lombardo,

  • Michael J. Racz,

  • Edward L. Hannan,

  • Elliott S. Fisher


  • This work was supported by VHA Health Services Research and Development Grants ACC 01-117-1 and REA 03-098. The views expressed in this article do not necessarily represent the views of the Department of Veterans Affairs, the United States' government, or the State of New York.

Abstract

Objective. To determine whether patients' use of the Veterans Health Administration health care system (VHA) is an independent risk factor for mortality following coronary artery bypass grafting (CABG) in the private sector in New York.

Data Sources. VHA administrative and New York Department of Health Cardiac Surgery Reporting System (CSRS) databases for surgeries performed in 1999 and 2000.

Study Design. Prospective cohort study comparing observed, expected, and risk-adjusted mortality rates following private sector CABG for 2,326 male New York State residents aged 45 years and older who used the VHA (VHA users) and 21,607 who did not (non-VHA users).

Data Collection Methods. We linked VHA administrative databases to New York's CSRS to identify VHA users who obtained CABG in the private sector in New York in 1999 and 2000. Using CSRS risk factors and previously validated risk-adjustment model, we compared patient characteristics and expected and risk-adjusted mortality rates of VHA users to non-VHA users.

Principal Findings. Compared with non-VHA users, patients undergoing private sector CABG who had used the VHA were older, had more severe cardiac disease, and were more likely to have the following comorbidities associated with increased risk of mortality: diabetes, chronic obstructive pulmonary disease, cerebrovascular disease, peripheral vascular disease, and history of stroke (p<.001 for all); a calcified aorta (p=.009); and a high creatinine level (p=.003). Observed (2.28 versus 1.80 percent) and expected (2.48 versus 1.78 percent) mortality rates were higher for VHA users than for non-VHA users. The risk-adjusted mortality rate for VHA users (1.70 percent; 95 percent confidence interval [CI]: 1.27–2.22) was not statistically different than that for the non-VHA users (1.87 percent; 95 percent CI: 1.69–2.06). Use of the VHA was not an independent risk factor for mortality in the risk-adjustment model.

Conclusions. Although VHA users had a greater illness burden, use of the VHA was not found to be an independent risk factor for mortality following private sector CABG in New York. The New York Department of Health risk adjustment model adequately applies to veterans who obtain CABG in the private sector in New York.

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