Hartford-based Aetna said it is the first national health care plan to sign a participating provider agreement with the Department of Veterans Affairs (VA) to cover plan members who also receive health care services from the VA. As part of the agreement, Aetna will recognize health care providers with the VA as in-network providers for all Aetna health plans. The VA, which has 153 hospitals, 881 outpatient clinics and 135 nursing homes, is the largest integrated health care system in the country.