Luboga SA, Stover B, Lim TW, Makumbi F, Kiwanuka N, Lubega F, Ndizihiwe A, Mukooyo E, Hurley EK, Borse N, Wood A, Bernhardt J, Lohman N, Sheppard L, Barnhart S, Hagopian A. Did PEPFAR investments result in health system strengthening? A retrospective long