Study State Health Plan Design: Creates a sixteen-member Joint Legislative Study Committee on the Sustainability of the North Carolina State Health Plan as title indicates. Directs the study to consider multiple issues relating to State Health Plan Design. Requires that the Committee report to the General Assembly by April 1, 2020, at which time the Committee will terminate. Requires that from January 1, 2019, through December 31, 2021, the State Treasurer, the State Health Plan for Teachers and State Employees (State Health Plan), the Board of Trustees of the State Health Plan, and the Executive Administrator of the State Health Plan continue to use the Blue Cross Blue Shield of North Carolina Blue Options provider network and to reimburse participating network providers in accordance with 100% of the applicable fee schedule. Also prohibits using any reference-based pricing model to reimburse providers during this same period.