Sole Community Hospital Preservation Act of 2005 - Amends title XVIII (Medicare) of the Social Security Act with respect to the prospective payment system (PPS) for hospital outpatient department (OPD) services, particularly the transitional adjustment for sole community hospitals to limit any decline in payment. Holds sole community hospitals permanently harmless from any decline in payment. Increases the payment for covered OPD services in a sole community hospital by the amount of any difference between the pre-Balanced Budget Act of 1997 (pre-BBA) amount and a lesser PPS amount.
Directs the Secretary of Health and Human Services to substitute a specified minimum base payment-to-cost ratio for determining the pre-BBA amount for sole community hospitals.
Specifies the rebasing of the payment -to-cost ratio for sole community hospitals for cost reporting periods beginning on or after October 1, 2005.