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

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.

Veterans Health Administration Patients’ Use of the Private Sector for Coronary Revascularization In New York

“…However, we recently found that the risk-adjustment model used by New York State applies well to male VA patients who use the private sector for CABG. 18 Fourth, our analysis assumes 100% patient compliance with direction of care. Established practice and referral patterns and patient indifference toward publicly reported data suggest that an active role is required to achieve the potential benefits of directed care that we project.…”

“…Both enrollment and vesting are used to define the VA service population-essentially the "covered lives" for whom VA has a potential medical benefits liability-and replicate methods used previously. 9,17,18 We excluded 46,855 VA patients who were younger than 45 years of age because few CABG operations are obtained by this age group, both historically 19 and during the time of this study (only 3% of all CABG operations performed in New York in 1999 and 2000 were on patients younger than 45 years of age). We also excluded 5514 women from the analysis because women represent such a small portion (1.7%) of the veteran user population that is at least 45 years of age.…”

Who Pays When VA Users Are Hospitalized in the Private Sector?

“…From the PTF and VA-Medicare data for 1998 through 2000, we selected enrollees who lived in and were hospitalized in New York State, so as to correspond to the coverage of our second dataset, which merges PTF data with any private sector UB-92 hospital discharge data for VA enrollees living in New York during those years. The VA&UB-92 dataset was created (for prior studies 11,12 ) by linking VA enrollment files to New York's Statewide Planning and Research Cooperative System database, which collects discharge information, including payer information, from all New York hospitals except VA hospitals. The linkage was done with a matching algorithm that used letters from patients' names, digits from social security numbers, and birthdates.…”

“…One dataset, which was developed for previous reports, 11,12 includes administrative UB-92 discharge data for all admissions to VA or private sector hospitals in New York State for veterans who lived there and were enrolled in VA healthcare. The other comprises hospitalization information drawn from Agency for Healthcare Research and Quality's (AHRQ) nationwide Medical Expenditure Panel Survey (MEPS), which is a large annual health survey of the noninstitutionalized civilian population; MEPS also specifies whether each respondent is a veteran or uses any VA healthcare.…”

Comparing the Characteristics, Utilization, Efficiency, and Outcomes of VA and Non-VA Inpatient Care Provided to VA Enrollees

“…Both enrollment and vesting are used to define the VA service population-essentially the "covered lives" for whom VA has a potential medical benefits liability-and replicate methods used previously. 7,16,17 Our dataset of New York VA enrollees included information on patients' date of birth, zip code of residence, gender, and service connected disability status.…”