Medicare's Elderly Receiving Innovative Treatments (MERIT) Act of 1999

Medicare's Elderly Receiving Innovative Treatments (MERIT) Act of 1999 - Amends part C (Medicare+Choice) of title XVIII (Medicare) of the Social Security Act with regard to the frail elderly by modifying: (1) payment rules (including requiring the Secretary of Health and Human Services to develop and implement a new payment system); (2) eligibility, election, and enrollment provisions (adding special rules for frail elderly Medicare+Choice beneficiaries enrolling in specialized programs for the frail elderly that establish a continuous open enrollment period for such individuals); and (3) benefits and beneficiary protections provisions (requiring the Secretary to develop and implement a program to measure the quality of care provided in specialized programs for the frail elderly). Exempts Medicare+Choice beneficiaries in a specialized program for the frail elderly from any risk adjustment system until the Secretary certifies to Congress that a comprehensive risk adjustment methodology taking certain factors into account is being fully implemented.