ABSTRACT

Over the past 15 years the patient books – known as case record forms (CRFs) – used in clinical trials have become increasingly standardized to facilitate comparisons of results from different trials and to allow for computerized data handling. The CRFs register patient history, physical examination data, medications taken, effect variables, laboratory values, and adverse experiences at each or every second visit to the doctor. When analyzing data from a clinical trial, the conventional method has been to treat effect variables and adverse experiences in a similar way. A prerequisite for an effect variable is the existence of a measurable condition, e.g., blood pressure, heart rate, or ulcer size, in all patients taking part in the clinical trial. Such variables are measured either on predetermined occasions or continuously, as with angina attacks, during a given period of time by means of diary cards.