Caritas Christi Health Care, a hospital chain owned by the Archdiocese of Boston, is dropping a longstanding strategy in which doctors at its five community hospitals have been pressured to refer as many patients as possible to its flagship facility. Doctors will have more freedom to refer patients to whichever institution will provide low-cost, high-quality care, said Caritas chief executive Ralph de la Torre, MD. That will enable the community hospitals to keep more high-paying procedures. Until the change was made, community hospital referrals have acted to subsidize the flagship hospital.