CBOCs represent one of VA's main managed care strategies for shifting the focus of care from the inpatient to the outpatient setting and for improving the health of our nation's veterans. Hypothesis-driven research is critically needed to test the basic assumptions motivating the expansion of CBOCs throughout the VA health care system.
The purpose was to determine how increased geographic access to primary care services affects service use and costs. Two specific aims addressed were: 1) to determine how CBOCs impact the service use of all existing users and existing users with the following ambulatory care sensitive conditions (ACSC): alcohol dependence, angina, chronic obstructive pulmonary disease (COPD), depression, diabetes and hypertension; and 2) to describe how CBOCs affect the workload and costs of the VA health care system from the VISN's perspective.
A quasi-experimental pre-post study design with intervention and reference groups was employed to compare service use and costs in the 18 months following the establishment of a new CBOC. Fifteen CBOCs from 11 VISNs were included in the analysis. For specific aim 1, the intervention group was defined as existing users in the catchment area of a new CBOC and the reference group was defined as matched existing users outside CBOC catchment areas. Multivariate statistical regression analyses were used to estimate the impact of residing within the CBOC catchment area on use and cost in the post-period, controlling for patient casemix and use/cost in the 18 month pre-period. For specific aim 2, the intervention group was defined as zip codes in the catchment area of a new CBOC and the reference group was defined as matched zip codes outside CBOC catchment areas. Average use and costs for all users, existing users and new users from intervention zip codes and reference zip codes were compared.
For aim 1, veterans in the all-diagnoses intervention sample traveled on average 42.9 miles to the closest VA facility in the pre-period compared to 19.1 miles in the post-period. However, the proportions of existing users in the CBOC catchment areas who used the CBOC in the intervention groups were relatively low: all diagnoses (18.1%), alcohol (17.1%), angina (17.5%), COPD (18.6%), depression (15.0%), diabetes (20.2%), and hypertension (21.5%). Existing users in 4 intervention groups (all-diagnoses, alcohol, COPD and hypertension) had significantly more primary care encounters in the post-period than existing users in the reference groups. Existing users in two intervention groups (all-diagnoses and diabetes) also had more ancillary encounters in the post-period than existing users in the reference groups. However, there were few differences in the number of specialty outpatient encounters, inpatient admissions or costs. These results indicate that while CBOCs improved geographic access to primary care, relatively few existing users sought treatment from the CBOCs and there were only modest increases in the use of primary care services. For aim 2, from the 18 month pre-period to the 18 month post-period, the total number of unique users increased by 37% in the intervention group zip codes compared to 19% in the reference group zip codes. These changes reflect both increases in the numbers of new users and decreases in the number of existing users. The proportion of new users in the intervention group zip codes was 45.5% compared to 38.8% for the reference group zip codes. Although new users had substantially less encounters, admissions and costs than existing users, there were few substantial differences in the average number of encounters, admissions and costs between veterans in intervention zip codes and reference zip codes.
It appears that CBOCs are having only a modest impact on existing users in their catchment areas (mostly in terms of increased primary care encounters). However, CBOCs are helping to attract new users to the VHA health system, and these new users have substantially lower utilization and costs than existing users.
- Fortney JC, Maciejewski ML, Warren JJ, Burgess JF. Does improving geographic access to VA primary care services impact patients' patterns of utilization and costs? Inquiry : A Journal of Medical Care Organization, Provision and Financing. 2005 Jan 1; 42(1):29-42.
- Maciejewski ML. A Heteroskedastic Adjustment for the Two-Part Model. Paper presented at: Health Policy Research Annual International Conference; 2003 Oct 1; Chicago, IL.