Edwin Wong and colleagues are on it. The first paragraph below pertains to outpatient care, the others to inpatient care:
Poor economic conditions have been associated with an uptake in VA outpatient health services, particularly among veterans who are exempt from copayments and thus have a financial incentive to seek VA care (Wong & Liu, 2013; Wong et al., 2014). […]
Among elderly patients using the VA system, local unemployment was not associated with the probability of being hospitalized in VA, FFS Medicare, or either system. However, sensitivity analyses suggested differences in the association between local unemployment and hospitalization probability according to whether patients were exempted from VA copayment requirements. For veterans subject to copayments, higher local unemployment was moderately associated with a greater probability of seeking inpatient care from VA. This positive association was accompanied by a negative, but nonsignificant unemployment rate marginal effect obtained from the Medicare inpatient model. The marginal effect for total hospitalizations was close to zero and not statistically significant. Taken together, these results are suggestive of modest substitution between Medicare and VA inpatient use attributable to higher local unemployment. VA may provide a more financially favorable option for some veterans who were subject to a $220 VA inpatient copayment compared with the $1,132 Medicare deducible in 2011. […]
Collectively, these results suggest the substitution effect exhibited by veterans subject to copayments was not present among low-income copayment-exempt VA enrollees, and that these veterans may have delayed or forgone inpatient care because of economic reasons.