Introduction | Data Structure and Extraction Process | Structure of CPRD Aurum data | Recommended process for extraction | Worked example for data extraction | Steps 1 - 4: Defining a cohort | Step 5: Reading in data and creating an SQLite database | Add individual files to SQLite database using add_to_database | Add all relevant files to SQLite database using cprd_extract | Add all relevant files to SQLite database in a computationally efficient manner using the set functionality. | Step 6: Querying the SQLite database to extract variables | Functions for extracting common variable types | Functions for extracting specific variables | Functions for database queries and custom variable extraction | Saving extracted variables directly to a disk drive, and utilising rAURUMs suggested directory system | Extracting longitudinal data/time varying covariates | Working with linked data | Discussion | References

Introduction | Algorithms for variable extraction | BMI (extract_BMI) | Cholesterol/HDL ratio (extract_cholhdl_ratio) | Diabetes status (extract_diabetes) | Smoking status (extract_smoking) | Summary of units of measurement for test data