This study compared the use of outpatient services in VA and Medicare among Medicare-eligible veterans who obtained primary care in VA community clinics or hospital outpatient clinics followed over 4 subsequent years. These results indicate that the most frequent source for primary care over time was to obtain care only from VA, particularly for hospital-based patients. In contrast, specialty care was obtained most commonly by dual use of both VA and Medicare (45–50 percent). The proportions of patients who used both VA and Medicare for primary and specialty care services remained stable over time for both hospital-based and community-based primary care patients. However, use of Medicare only for primary care and specialty care increased during the 4-year observation period, while use of VA only for these outpatient services decreased. Resources in VA for advanced specialty care during this period were generally flat and not expanding, which could be driving this result. The most frequent source for the relatively small proportion of Medicare-eligible veterans who used mental health care services was to obtain care only from VA, a special emphasis service for VA that was expanding during this period.
This study design, following a cohort over 4 years, shows patterns of individual care in ways not possible through examination of aggregate statistics of varying patient compositions. The study shows that the level of fragmentation varies across types of outpatient care and over time. Veterans' specialty care was the most fragmented type of outpatient care, with dual use being the common pattern of care among both community-based and hospital-based patients. Primary care also was fragmented, although less so for hospital-based patients than for community-based patients, suggesting that increasing access to VA primary care via community clinics may fragment outpatient care in unintended ways. This primary care fragmentation, shifting toward Medicare-financed care, increases faster over time in the community-based cohort.
Fragmentation of primary care and specialty care, and trends over time for 2001–2004 suggest that dual users of VA and Medicare would benefit from the integration of health information systems in real time to ensure information continuity between VA and Medicare providers. San Diego VA Medical Center and Kaiser Permanente have recently begun testing shared electronic medical records (Chambers 2010
). As more than 30 percent of Medicare-eligible veterans in our study used primary care covered by Medicare and 60 percent used specialty care covered by Medicare, integration of clinical information from Medicare providers into the VA system would affect a large proportion of Medicare-eligible veterans.
These results are consistent with a previous study of veterans from rural settings in three northern New England states (Weeks et al. 2005a
). The decrease in the proportion of patients using VA-only primary care could be in part due to regression to the mean, because primary care use in VA at baseline was one of the inclusion criteria for the study cohort. The increase in the proportion of patients using Medicare only implies a shift from VA to Medicare as the cohort ages.
Community-based patients use less VA primary care and specialty care over time compared with hospital-based patients but appear to be offsetting this lower VA use with greater use of services covered by Medicare, rather than using fewer services overall. This finding provides an important context to our earlier papers (Fortney et al. 2002
; Maciejewski et al. 2002
) and modifies earlier conclusions that community-based patients had fewer visits and were healthier compared with hospital-based patients. In contrast, this study shows that a lower outpatient service use by community-based patients is true only from the VA perspective, and that there is no significant difference in the DCG risk scores for community-based and hospital-based patients when both VA and Medicare data are used. The risk adjustment and assessment conclusions here are important. Because VA sees only the diagnoses and care from their system, we may systematically underestimate the illness burden and risk for these veterans. These results demonstrate clearly that VA managers must assess total utilization to fully characterize the quality of care and cost experience of Medicare-eligible veterans (Rosen et al. 2005
Increasing non-VA primary and specialty care use by definition affects the continuity of care and may also impact chronic disease management. Further understanding of the patterns of care and the causes of dual use and switching between systems is important to clarify the ramifications of this widespread, apparent fracturing of care for veterans.
This study shows that mental health was not fragmented among VA primary care patients, because most veterans did not use mental health services and users predominantly went entirely to VA for mental health care (Weeks et al. 2005
; Liu et al. 2009
;). The lower use of mental health services paid by Medicare may also reflect the limited mental health coverage under Medicare. Therefore, the impacts of non-VA use may be minimal for mental health care because of high reliance on VA for this type of care. Our study concurs with other recent research on this question (McCarthy et al. 2008
This study has several limitations. This is not a random sample of Medicare-eligible veterans in the VA system. Next, the study does not include utilization data provided under other insurance coverage, including Medicaid and private insurance. Further, these results show veteran experience in 2001–2004 before the implementation of Medicare Part D, and so these results may not generalize to more current experience of veterans facing different choices. However, VA pharmaceutical prices and policies have remained attractive to veterans thus far. The study cohort also precedes the influx of returning veterans from the Afghanistan and Iraq wars, which has resulted in considerable increases in VA budgets and provision of more specialty care aimed at these younger veterans. Finally, there could be important unobserved confounding that might help explain the differences between community-based and hospital-based patients because we did not initially randomize patients into community clinics or hospital outpatient clinics.
This study makes several unique contributions. It is the first geographically dispersed cohort study to examine primary care, specialty care, and mental health care visits by veterans in VA and Medicare using the same definition of visit types in both systems. We also examined changes over time to understand trends in veteran use of care for a fixed cohort within each system for specific types of outpatient care to understand whether VA reliance differs across types of outpatient care following individual VA system users over time. Lastly, we examined differences in outpatient service use between community-based and hospital-based patients, which may create problems for coordination, continuity, and quality of care.
Overall, we found high use of outpatient services financed by Medicare among VA primary care patients for both primary and specialty care, but not mental health care. Patients enrolled in community clinics appear to offset decreased VA use with increased use of primary care and specialty care covered by Medicare, but not mental health care. By the end of the observation period, many VA hospital-based primary care patients and most community-based patients obtained at least some primary and specialty care outside the VA. Therefore, assessing total utilization across VA and Medicare systems is necessary to fully anticipate health care needs among Medicare-eligible veterans. Further, the dual use of VA and Medicare outpatient services may impact chronic disease management and continuity of care, and have profound implications for provider, facility, and system quality measurement, particularly for VA community-based primary care patients.