Background: People with multimorbidity experience impaired quality of life, poor health and a burden from treatment. Their care is often disease-focused rather than patient-centred and tailored to their individual needs. Objective: To implement and evaluate a patient-centred intervention to improve the management of patients with multimorbidity in general practice. Design: Pragmatic, cluster randomised controlled trial with parallel process and economic evaluations. Practices were centrally randomised by a statistician blind to practice identifiers, using a computer-generated algorithm. Setting: Thirty-three general practices in three areas of England and Scotland. Participants: Practices had at least 4500 patients and two general practitio...