; (ii) veterans who are enrolled in the patient enrollment system of the Department of Veterans Affairs under section 1705(a) of title 38, United States Code, as compared to veterans who have never enrolled in such system; (iii) veterans who have recently used services from a Vet Center as compared to veterans who have never used such services; (iv) veterans who have a diagnosis of substance use disorder; and (v) other groups of veterans relating to engagement with health care from the Veterans Health Administration, as the Secretary considers practicable. (C) Trends in suicide rates of veterans compared to engagement of those veterans with benefits from the Veterans Benefits Administration, including an examination of trends in suicide rates or deaths among— (i) veterans who are currently using, have previously used, or have never used educational assistance under the laws administered by the Secretary; (ii) veterans who are currently receiving, have previously received, or have never received services or assistance under chapter 31 of title 38, United States Code; (iii) with respect to compensation under chapter 11 of such title— (I) veterans who were recipients of such compensation as compared to veterans who never applied for such compensation prior to death; (II) veterans who had a claim denied for such compensation prior to death; (III) veterans who had a pending claim for such compensation at time of death; and (IV) veterans who had an entitlement for such compensation reduced prior to death; (iv) veterans who are currently receiving or have never received pension under chapter 15 of title 38, United States Code; (v) veterans who are currently using, have previously used, or have never used programs or services provided by the Homeless Programs Office of the Department, including an examination of trends in suicide rates or deaths among veterans who made contact with such office but were denied or deemed ineligible for any such program or service