Optimum Patient Care Research Database (OPCRD) holds anonymous data from over 700 general practices in UK and approximately 8.8 million patients. The Optimum Patient Care Research Database (OPCRD) is a primary care dataset from over 700 practices across the UK covering over 7.3 million patients augmented with respiratory questionnaire and clinical review data. OPCRD is established and maintained by Optimum Patient Care (OPC), a UK based social enterprise. OPC is guided by leading clinical and academic experts, it is one of the biggest primary care research networks in the world. The anonymous electronic medical records and patient questionnaires collected within OPCRD provide an essential source of real world data to promote evidence based research and quality improvement. OPC has grown to become a global leader in the provision of technologically enhanced health care data and clinical research services.