A system and method to input patient data including previous diagnosis, drugs, symptoms and treatment, open data and expert knowledge, and to use these inputs to create a patient clinical object (PCO), biomedical knowledge and rule based knowledge graphs, and to enrich the PCO using the biomedical knowledge graph. A meta diagnosis predictor is to use the PCO and the biomedical knowledge graph and/or the rule based knowledge graph in plural predictors of a diagnosis-based predictor to provide a set of diagnoses based on previous diagnoses, a drug-based predictor to provide a set of diagnoses based on drugs taken by the patient, a symptom-based predictor to provide a set of diagnoses based on symptoms of the patient and a treatment-based predictor to provide a set of diagnoses based on the treatments. Any of the sets of diagnoses may be combined to give a predicted primary diagnosis for the patient.