Chronic obstructive pulmonary disease research by using big data.

As the information technology develops, large amount of data has been stored. The digitalisation of the health-care system enables researchers to use big data easily. Big data have been utilised for valuable source for chronic obstructive pulmonary disease (COPD) research. Various sources of data are now available including nationwide claim data and primary care database. Recently, web data are also used in COPD research. Each different data source has strengths and weaknesses. Merging different data can overcome the limitation of big data research. Future direction of big data research is to integrate multiple big data.